Contact Lenses, Hydrophilic
Silicones
Acanthamoeba Keratitis
Lenses
Acanthamoeba
Cornea
Corneal Ulcer
Prosthesis Fitting
Keratoconus
Aphakia
Corneal Edema
Corneal Topography
Eye Infections, Bacterial
Cataract
Lens Cortex, Crystalline
Lens Capsule, Crystalline
Eyeglasses
Lens Diseases
Disinfection
Lens Implantation, Intraocular
Hydrogels
Fusariosis
Myopia
Visual Acuity
Equipment Contamination
Presbyopia
Fluorophotometry
Polyhydroxyethyl Methacrylate
Astigmatism
Eye Infections, Fungal
Crystallins
Methylmethacrylates
Epithelium, Corneal
Lens Subluxation
Refractive Errors
Disinfectants
Eye Infections
Corneal Stroma
Eye
Orthokeratologic Procedures
Hygiene
Silicone Elastomers
Ophthalmic Solutions
Dry Eye Syndromes
Hyperopia
Contact Tracing
Interferometry
Conjunctiva
Accommodation, Ocular
Eye Proteins
Corneal Transplantation
Amebiasis
Dermatitis, Contact
Ophthalmodynamometry
Biguanides
Optics and Photonics
Keratoplasty, Penetrating
Dermatitis, Allergic Contact
Ophthalmology
Radiation Protection
Methacrylates
Lasers, Excimer
Pseudomonas aeruginosa
Conjunctivitis
Acanthamoeba castellanii
Amebicides
Fluorescein
Fusarium
Meibomian Glands
Eye Injuries
Corneal Endothelial Cell Loss
Diagnostic Techniques, Ophthalmological
Blinking
Conjunctival Diseases
Fungi
Epithelium
Epithelial Cells
Colony Count, Microbial
Lysozyme sorption in hydrogel contact lenses. (1/217)
PURPOSE: To examine the processes involved in formation of protein deposits on hydrogel contact lenses. METHODS: The adsorption and/or penetration of lysozyme on or into three types of contact lenses, etafilcon A, vifilcon A, and tefilcon, were investigated in vitro using a radiolabel-tracer technique, x-ray photoelectron spectroscopy, and laser scanning confocal microscopy. RESULTS: Binding of lysozyme to high-water-content, ionic contact lenses (etafilcon A and vifilcon A) was dominated by a penetration process. The extent of this penetration was a function of charge density of the lenses, so that there was a higher degree of penetration of lysozyme in etafilcon A than in vifilcon A lenses. In contrast, the binding of lysozyme to tefilcon lenses was a surface adsorption process. The adsorption and desorption kinetics showed similar trends to those found in human serum albumin (HSA) adsorption on lens surfaces. However, the extent of lysozyme adsorption on tefilcon is much higher than HSA adsorption, probably because of the self-association of lysozyme on the tefilcon lens surface. Furthermore, either penetration or adsorption of lysozyme involved reversible and irreversible processes and were both time dependent. CONCLUSIONS: Binding of lysozyme to hydrogel lenses involves surface adsorption or matrix penetration. These processes may be reversible or irreversible. The properties of the lens materials, such as charge density (ionicity) and porosity (water content) of the lenses, determine the type and rates of these processes. (+info)Measurement of post-lens tear thickness. (2/217)
PURPOSE: A method to measure the tear film beneath a soft contact lens, referred to as post-lens tear thickness (PLTT), would have many applications to contact lens research. In this study a noninvasive technique for measuring the PLTT is presented. METHODS: The feasibility of measuring the tear layer by optical pachometry was first assessed using a model eye. The baseline corneal thickness (B) of both eyes of 21 subjects was measured, etafilcon-A ionic disposable soft contact lenses (58% water) were inserted, and the total thickness (T) of the cornea, contact lens, and PLTT were measured. After the pachometry readings the lenses were removed and their center thickness (C) determined. The PLTT was calculated using the equation: PLTT = T-(B+C). Two sets of measurements of T were performed at 15 and 25 minutes after lens insertion. The entire procedure was repeated at a second visit. RESULTS: The pachometry measurements of the small aqueous reservoir between the model eye and the lens closely matched those obtained by direct microscopic measurement. For human PLTT, the mean values (and 95% confidence intervals) for right eyes on visits 1 and 2 were 11 (8, 13) and 12 (10, 15) microm, respectively, and for left eyes were 12 (10, 15) and 11 microm (8, 14) microm, respectively. CONCLUSIONS: It is possible to measure the post-lens tear thickness using optical pachometry. The variability between repeated measurements suggests that with careful sample size planning, the technique is sufficiently precise to be useful in group assessments of PLTT. (+info)Sympathetic swelling response of the control eye to soft lenses in the other eye. (3/217)
PURPOSE: To compare central corneal swelling and light scatter after 8 hours of sleep in eyes wearing high- and low-Dk hydrogel lenses and to the contralateral control eyes. METHODS: Twenty neophyte subjects wore a Lotrafilcon A (Dk, 140; Ciba Vision, Duluth GA) silicone hydrogel lens and an Etafilcon A (Dk, 18; Acuvue; Vistakon, Jacksonville, FL) 58% water content hydrogel lens of similar center thickness in random order in the right eye only, for overnight 8-hour periods. The contralateral nonwearing left eyes served as controls. Central corneal thickness was measured using an optical pachometer and light scatter using a Van den Berg stray-light meter before lens insertion, after lens removal on waking, and every 20 minutes for the next 3 hours. RESULTS: Central corneal swelling induced by the Etafilcon A lens on eye opening was significantly higher than with the Lotrafilcon A lens (8.66%+/-2.84% versus 2.71%+/-1.91%; P<0.00001). Light scatter induced by the Etafilcon A lens on eye opening was significantly higher than with the Lotrafilcon A lens (46.09+/-5.62 versus 42.78+/-6.07 Van den Berg units, P = 0.0078). The swelling of the control eyes paired with the Etafilcon A lens-wearing eyes was also slightly but significantly higher than that of the control eyes paired with the Lotrafilcon A lens-wearing eyes (2.34%+/-1.26% versus 1.44%+/-0.91%; P = 0.0002). Light-scatter measurements were not significantly different between control sets of eyes but showed the same trend. CONCLUSIONS: In neophyte subjects, corneal swelling of the contralateral control eyes appears to be influenced by the swelling of the fellow lens-wearing eyes-that is, the swelling of the contralateral control eye was significantly lower when there was less swelling of the fellow eye wearing the high-Dk lens. Although there was no statistically significant difference in light-scatter measurements between the control sets of eyes, a trend similar to the corneal swelling results was observed, which could be used to support the suggestion that this may be a sympathetic physiological response rather than an unusual sampling coincidence. (+info)Observation of soft contact lens disinfection with fluorescent metabolic stains. (4/217)
A rapid fluorescent staining method using a tetrazolium dye and propidium iodide for the in-use assessment of disinfection of Pseudomonas aeruginosa biofilms on soft contact lenses showed that 11 to 13% of cells on lenses remained actively respiring and recoverable by culture methods after 30 min of exposure to 3% hydrogen peroxide. (+info)Unusual case of Acanthamoeba polyphaga and Pseudomonas aeruginosa keratitis in a contact lens wearer from Gauteng, South Africa. (5/217)
Acanthamoeba species can cause a chronic, progressive ulcerative keratitis of the eye which is not responsive to the usual antimicrobial therapy and is frequently mistaken for stromal herpes keratitis. An unusual case of coinfection with Acanthamoeba polyphaga and Pseudomonas aeruginosa as causes of corneal keratitis in a contact lens wearer from Gauteng, South Africa, is reported. These two pathogens have previously been assumed to be selectively exclusive. Cysts of the isolated acanthameba tolerated an incubation temperature of 40 degrees C, indicating a pathogenic species. This case highlights the importance of culture methods in the diagnosis of corneal infection and the choice of treatment regimen. The patient's history of careless contact lens-disinfecting habits emphasizes the need to adhere strictly to recommended methods of contact lens care. (+info)Apoptosis in shed human corneal cells. (6/217)
PURPOSE: To determine whether shear forces applied to the corneal epithelium by the repeated insertion and removal of a hydrogel contact lens alter the size and number of cells removed and to determine the contribution of apoptosis to this process. METHODS; Human corneal cells were collected from eight healthy subjects by sequential contact lens cytology (20 lens insertions and removals). Collected cells were stained with acridine orange for counting and measurement of cell size. In a separate experiment, collected cells were fixed and stained with TdT-mediated dUTP nick-end labeling (TUNEL) or labeled immediately after collection using annexin V. Hoechst stain and propidium iodide (PI) were used as nuclear counterstains. The proportion of cells labeled with acridine orange, TUNEL, and annexin V was quantified by fluorescence microscopy. RESULTS; The number of cells increased in later collections, and cells were smaller. The mean number of positively stained cells using TUNEL was 57%. Annexin V labeling on unfixed fresh samples showed a mean of 64%, with an increase in later collections. Apoptotic bodies were observed in very few cells. In most cells the nucleus and cytoplasmic membrane were intact. Structures were observed in which nuclei were missing (Hoechst negative) but in which cytoplasm had the size and appearance of whole, nucleated cells. These structures (cell ghosts) increased in number along with the increase in nucleated cells in later collections. CONCLUSIONS: The sequential removal of a soft contact lens caused a progressive increase in the number of cells collected from the surface and a progressive decrease in their size. The majority of nucleated cells removed by a contact lens were apoptotic in the sense of being positively labeled by TUNEL and annexin V. Morphologically they differed from classically apoptotic cells, in that cells showed an intact nuclear structure and no discernible apoptotic bodies. They could represent a last stage in a pathway of cell differentiation in which frictional forces induced by the removal of the contact lens activate the apoptotic program and cause the cell to be shed. There is also a pathway in which cells lose their nuclei before leaving the epithelial surface. (+info)Optical and visual impact of tear break-up in human eyes. (7/217)
PURPOSE: The purpose of this study was to examine the optical and visual impact of tear break-up. METHODS: Optical quality of the eye was assessed during periods of nonblinking by quantifying vessel contrast in the fundus image and by monitoring the psychophysical contrast sensitivity and the spatial distribution of tear thickness changes by retroillumination. All measures were obtained from three eyes either with or without a soft contact lens. RESULTS: A noticeable decrease in retinal vessel contrast and contrast sensitivity were observed soon after a blink. Both of these measures of optical quality of the eye showed a similar pattern of image degradation both with and without a soft contact lens. Although trial-to-trial variability was considerable, sample means show that image contrast in the low spatial frequency range can drop to between 20% and 40% of initial values after 60 seconds of nonblinking. Retroillumination of the tear film showed local intensity fluctuations that progressively spread across the pupil with increasing time after the blink. CONCLUSIONS: Optical aberrations created by tear break-up contribute to the decline in image quality observed objectively and psychophysically. The decline in image quality that accompanies tear break-up may be a direct cause of the blurry vision complaints commonly encountered in dry-eye patients. (+info)Bacterial colonization of disposable soft contact lenses is greater during corneal infiltrative events than during asymptomatic extended lens wear. (8/217)
Microorganisms, especially gram-negative bacteria, are considered to play a role in the etiology of certain corneal infiltrative events (CIEs) observed during soft contact lens wear. This study explored the possibility of microbial colonization of soft contact lenses as a risk factor leading to CIEs. In a clinical trial conducted from March 1993 to January 1996, 330 subjects wore disposable soft contact lenses on a 6-night extended-wear and disposal schedule. During this period, 4,321 lenses (118 during CIEs; 4,203 during asymptomatic lens wear) were recovered aseptically and analyzed for microbial colonization. A greater percentage of lenses were free from microbial colonization during asymptomatic wear than during CIEs (42 versus 23%; P < 0.0001). The incidence of gram-positive bacteria, gram-negative bacteria and fungi was greater during CIEs than during asymptomatic lens wear (P < 0.05). During asymptomatic lens wear, gram-positive bacteria were isolated most frequently and were usually normal external ocular microbiota. Of the gram-positive bacteria, the incidence of Streptococcus pneumoniae was greater during CIE than during asymptomatic wear (7.6 versus 0.6%; P < 0. 0001). While gram-negative bacteria were seen in few cases during asymptomatic wear, their incidence during CIE in comparison to asymptomatic wear was substantial and significant (23.7 versus 3.8%; P < 0.0001). Also, the level of colonization was high. Of CIEs, events of microbial keratitis, contact lens acute red eye, and asymptomatic infiltrative keratitis were associated with lens colonization with gram-negative bacteria or S. pneumoniae. Colonization of soft contact lenses with pathogenic bacteria, especially gram-negative bacteria and S. pneumoniae, appears to be a significant risk factor leading to CIE. (+info)Contact lenses are thin, curved plastic or silicone hydrogel devices that are placed on the eye to correct vision, replace a missing or damaged cornea, or for cosmetic purposes. They rest on the surface of the eye, called the cornea, and conform to its shape. Contact lenses are designed to float on a thin layer of tears and move with each blink.
There are two main types of contact lenses: soft and rigid gas permeable (RGP). Soft contact lenses are made of flexible hydrophilic (water-absorbing) materials that allow oxygen to pass through the lens to the cornea. RGP lenses are made of harder, more oxygen-permeable materials.
Contact lenses can be used to correct various vision problems, including nearsightedness, farsightedness, astigmatism, and presbyopia. They come in different shapes, sizes, and powers to suit individual needs and preferences. Proper care, handling, and regular check-ups with an eye care professional are essential for maintaining good eye health and preventing complications associated with contact lens wear.
Hydrophilic contact lenses are a type of contact lens that is designed to absorb and retain water. These lenses are made from materials that have an affinity for water, which helps them to remain moist and comfortable on the eye. The water content of hydrophilic contact lenses can vary, but typically ranges from 30-80% by weight.
Hydrophilic contact lenses are often used to correct refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. They can be made in a variety of materials, including soft hydrogel and silicone hydrogel.
One advantage of hydrophilic contact lenses is that they tend to be more comfortable to wear than other types of contacts, as they retain moisture and conform closely to the shape of the eye. However, they may also be more prone to deposits and buildup, which can lead to protein accumulation and discomfort over time. Proper care and cleaning are essential to maintain the health of the eyes when wearing hydrophilic contact lenses.
Contact lens solutions are a type of disinfecting and cleaning solution specifically designed for use with contact lenses. They typically contain a combination of chemicals, such as preservatives, disinfectants, and surfactants, that work together to clean, disinfect, and store contact lenses safely and effectively.
There are several types of contact lens solutions available, including:
1. Multipurpose solution: This type of solution is the most commonly used and can be used for cleaning, rinsing, disinfecting, and storing soft contact lenses. It contains a combination of ingredients that perform all these functions in one step.
2. Hydrogen peroxide solution: This type of solution contains hydrogen peroxide as the main active ingredient, which is a powerful disinfectant. However, it requires a special case called a neutralizer to convert the hydrogen peroxide into water and oxygen before using the lenses.
3. Saline solution: This type of solution is used only for rinsing and storing contact lenses and does not contain any disinfecting or cleaning agents. It is often used in combination with other solutions for a complete contact lens care routine.
4. Daily cleaner: This type of solution is used to remove protein buildup and other deposits from the surface of contact lenses. It should be used in conjunction with a multipurpose or hydrogen peroxide solution as part of a daily cleaning routine.
It's important to follow the manufacturer's instructions carefully when using contact lens solutions to ensure that they are used safely and effectively. Failure to do so could result in eye irritation, infection, or other complications.
Keratitis is a medical condition that refers to inflammation of the cornea, which is the clear, dome-shaped surface at the front of the eye. The cornea plays an essential role in focusing vision, and any damage or infection can cause significant visual impairment. Keratitis can result from various causes, including bacterial, viral, fungal, or parasitic infections, as well as trauma, allergies, or underlying medical conditions such as dry eye syndrome. Symptoms of keratitis may include redness, pain, tearing, sensitivity to light, blurred vision, and a feeling of something foreign in the eye. Treatment for keratitis depends on the underlying cause but typically includes antibiotics, antivirals, or anti-fungal medications, as well as measures to alleviate symptoms and promote healing.
Silicones are not a medical term, but they are commonly used in the medical field, particularly in medical devices and healthcare products. Silicones are synthetic polymers made up of repeating units of siloxane, which is a chain of alternating silicon and oxygen atoms. They can exist in various forms such as oils, gels, rubbers, and resins.
In the medical context, silicones are often used for their unique properties, including:
1. Biocompatibility - Silicones have a low risk of causing an adverse reaction when they come into contact with living tissue.
2. Inertness - They do not react chemically with other substances, making them suitable for use in medical devices that need to remain stable over time.
3. Temperature resistance - Silicones can maintain their flexibility and elasticity even under extreme temperature conditions.
4. Gas permeability - Some silicone materials allow gases like oxygen and water vapor to pass through, which is useful in applications where maintaining a moist environment is essential.
5. Durability - Silicones have excellent resistance to aging, weathering, and environmental factors, ensuring long-lasting performance.
Examples of medical applications for silicones include:
1. Breast implants
2. Contact lenses
3. Catheters
4. Artificial joints and tendons
5. Bandages and wound dressings
6. Drug delivery systems
7. Medical adhesives
8. Infant care products (nipples, pacifiers)
Acanthamoeba keratitis is a rare but serious infection of the cornea, which is the clear outer layer at the front of the eye. It's caused by a microscopic organism called Acanthamoeba, which is commonly found in water and soil.
The infection typically occurs in people who wear contact lenses, particularly those who do not clean and disinfect their lenses properly or who swim or shower while wearing their contacts. It can cause pain, redness, blurry vision, sensitivity to light, and a feeling like there's something in your eye.
If left untreated, Acanthamoeba keratitis can lead to serious complications, including corneal scarring, loss of vision, or even blindness. Treatment typically involves the use of specialized antimicrobial drops and sometimes requires a corneal transplant in severe cases. Prevention measures include proper contact lens hygiene, avoiding swimming or showering while wearing contacts, and regularly replacing contact lens storage cases.
In the context of medical terminology, "lenses" generally refers to optical lenses used in various medical devices and instruments. These lenses are typically made of glass or plastic and are designed to refract (bend) light in specific ways to help magnify, focus, or redirect images. Here are some examples:
1. In ophthalmology and optometry, lenses are used in eyeglasses, contact lenses, and ophthalmic instruments to correct vision problems like myopia (nearsightedness), hypermetropia (farsightedness), astigmatism, or presbyopia.
2. In surgical microscopes, lenses are used to provide a magnified and clear view of the operating field during microsurgical procedures like ophthalmic, neurosurgical, or ENT (Ear, Nose, Throat) surgeries.
3. In endoscopes and laparoscopes, lenses are used to transmit light and images from inside the body during minimally invasive surgical procedures.
4. In ophthalmic diagnostic instruments like slit lamps, lenses are used to examine various structures of the eye in detail.
In summary, "lenses" in medical terminology refer to optical components that help manipulate light to aid in diagnosis, treatment, or visual correction.
Acanthamoeba is a genus of free-living, ubiquitous amoebae found in various environments such as soil, water, and air. These microorganisms have a characteristic morphology with thin, flexible pseudopods and large, rounded cells that contain endospores. They are known to cause two major types of infections in humans: Acanthamoeba keratitis, an often painful and potentially sight-threatening eye infection affecting the cornea; and granulomatous amoebic encephalitis (GAE), a rare but severe central nervous system infection primarily impacting individuals with weakened immune systems.
Acanthamoeba keratitis typically occurs through contact lens wearers accidentally introducing the organism into their eyes, often via contaminated water sources or inadequately disinfected contact lenses and solutions. Symptoms include eye pain, redness, sensitivity to light, tearing, and blurred vision. Early diagnosis and treatment are crucial for preventing severe complications and potential blindness.
Granulomatous amoebic encephalitis is an opportunistic infection that affects people with compromised immune systems, such as those with HIV/AIDS, cancer, or organ transplant recipients. The infection spreads hematogenously (through the bloodstream) to the central nervous system, where it causes inflammation and damage to brain tissue. Symptoms include headache, fever, stiff neck, seizures, altered mental status, and focal neurological deficits. GAE is associated with high mortality rates due to its severity and the challenges in diagnosing and treating the infection effectively.
Prevention strategies for Acanthamoeba infections include maintaining good hygiene practices, regularly replacing contact lenses and storage cases, using sterile saline solution or disposable contact lenses, and avoiding swimming or showering while wearing contact lenses. Early detection and appropriate medical intervention are essential for managing these infections and improving patient outcomes.
The cornea is the clear, dome-shaped surface at the front of the eye. It plays a crucial role in focusing vision. The cornea protects the eye from harmful particles and microorganisms, and it also serves as a barrier against UV light. Its transparency allows light to pass through and get focused onto the retina. The cornea does not contain blood vessels, so it relies on tears and the fluid inside the eye (aqueous humor) for nutrition and oxygen. Any damage or disease that affects its clarity and shape can significantly impact vision and potentially lead to blindness if left untreated.
In medical terms, "tears" are a clear, salty liquid that is produced by the tear glands (lacrimal glands) in our eyes. They serve to keep the eyes moist, protect against dust and other foreign particles, and help to provide clear vision by maintaining a smooth surface on the front of the eye. Tears consist of water, oil, and mucus, which help to prevent evaporation and ensure that the tears spread evenly across the surface of the eye. Emotional or reflexive responses, such as crying or yawning, can also stimulate the production of tears.
A corneal ulcer is a medical condition that affects the eye, specifically the cornea. It is characterized by an open sore or lesion on the surface of the cornea, which can be caused by various factors such as bacterial or fungal infections, viruses, or injury to the eye.
The cornea is a transparent tissue that covers the front part of the eye and protects it from harmful particles, bacteria, and other foreign substances. When the cornea becomes damaged or infected, it can lead to the development of an ulcer. Symptoms of a corneal ulcer may include pain, redness, tearing, sensitivity to light, blurred vision, and a white spot on the surface of the eye.
Corneal ulcers require prompt medical attention to prevent further damage to the eye and potential loss of vision. Treatment typically involves antibiotics or antifungal medications to eliminate the infection, as well as pain management and measures to protect the eye while it heals. In severe cases, surgery may be necessary to repair the damage to the cornea.
Prosthesis fitting is the process of selecting, designing, fabricating, and fitting a prosthetic device to replace a part of an individual's body that is missing due to congenital absence, illness, injury, or amputation. The primary goal of prosthesis fitting is to restore the person's physical function, mobility, and independence, as well as improve their overall quality of life.
The process typically involves several steps:
1. Assessment: A thorough evaluation of the patient's medical history, physical condition, and functional needs is conducted to determine the most appropriate type of prosthesis. This may include measurements, castings, or digital scans of the residual limb.
2. Design: Based on the assessment, a customized design plan is created for the prosthetic device, taking into account factors such as the patient's lifestyle, occupation, and personal preferences.
3. Fabrication: The prosthesis is manufactured using various materials, components, and techniques to meet the specific requirements of the patient. This may involve the use of 3D printing, computer-aided design (CAD), or traditional handcrafting methods.
4. Fitting: Once the prosthesis is fabricated, it is carefully fitted to the patient's residual limb, ensuring optimal comfort, alignment, and stability. Adjustments may be made as needed to achieve the best fit and function.
5. Training: The patient receives training on how to use and care for their new prosthetic device, including exercises to strengthen the residual limb and improve overall mobility. Follow-up appointments are scheduled to monitor progress, make any necessary adjustments, and provide ongoing support.
Disposable equipment in a medical context refers to items that are designed to be used once and then discarded. These items are often patient-care products that come into contact with patients or bodily fluids, and are meant to help reduce the risk of infection transmission. Examples of disposable medical equipment include gloves, gowns, face masks, syringes, and bandages.
Disposable equipment is intended for single use only and should not be reused or cleaned for reuse. This helps ensure that the equipment remains sterile and free from potential contaminants that could cause harm to patients or healthcare workers. Proper disposal of these items is also important to prevent the spread of infection and maintain a safe and clean environment.
Keratoconus is a degenerative non-inflammatory disorder of the eye, primarily affecting the cornea. It is characterized by a progressive thinning and steepening of the central or paracentral cornea, causing it to assume a conical shape. This results in irregular astigmatism, myopia, and scattering of light leading to blurred vision, visual distortions, and sensitivity to glare. The exact cause of keratoconus is unknown, but it may be associated with genetics, eye rubbing, and certain medical conditions. It typically starts in the teenage years and progresses into the third or fourth decade of life. Treatment options include glasses, contact lenses, cross-linking, and corneal transplantation in advanced cases.
Intraocular lenses (IOLs) are artificial lens implants that are placed inside the eye during ophthalmic surgery, such as cataract removal. These lenses are designed to replace the natural lens of the eye that has become clouded or damaged, thereby restoring vision impairment caused by cataracts or other conditions.
There are several types of intraocular lenses available, including monofocal, multifocal, toric, and accommodative lenses. Monofocal IOLs provide clear vision at a single fixed distance, while multifocal IOLs offer clear vision at multiple distances. Toric IOLs are designed to correct astigmatism, and accommodative IOLs can change shape and position within the eye to allow for a range of vision.
The selection of the appropriate type of intraocular lens depends on various factors, including the patient's individual visual needs, lifestyle, and ocular health. The implantation procedure is typically performed on an outpatient basis and involves minimal discomfort or recovery time. Overall, intraocular lenses have become a safe and effective treatment option for patients with vision impairment due to cataracts or other eye conditions.
Aphakia is a medical condition that refers to the absence of the lens in the eye. This can occur naturally, but it's most commonly the result of surgery to remove a cataract, a cloudy lens that can cause vision loss. In some cases, the lens may not be successfully removed or may be accidentally lost during surgery, leading to aphakia. People with aphakia typically have significant vision problems and may require corrective measures such as glasses, contact lenses, or an intraocular lens implant to improve their vision.
Corneal edema is a medical condition characterized by the accumulation of fluid in the cornea, which is the clear, dome-shaped surface at the front of the eye. This buildup of fluid causes the cornea to swell and thicken, resulting in blurry or distorted vision. Corneal edema can be caused by various factors, including eye injuries, certain medications, eye surgeries, and diseases that affect the eye's ability to pump fluids out of the cornea. In some cases, corneal edema may resolve on its own or with treatment, but in severe cases, it may require a corneal transplant.
Corneal topography is a non-invasive medical imaging technique used to create a detailed map of the surface curvature of the cornea, which is the clear, dome-shaped surface at the front of the eye. This procedure provides valuable information about the shape and condition of the cornea, helping eye care professionals assess various eye conditions such as astigmatism, keratoconus, and other corneal abnormalities. It can also be used in contact lens fitting, refractive surgery planning, and post-surgical evaluation.
Bacterial eye infections, also known as bacterial conjunctivitis or bacterial keratitis, are caused by the invasion of bacteria into the eye. The most common types of bacteria that cause these infections include Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae.
Bacterial conjunctivitis is an inflammation of the conjunctiva, the thin membrane that covers the white part of the eye and the inner surface of the eyelids. Symptoms include redness, swelling, pain, discharge, and a gritty feeling in the eye. Bacterial keratitis is an infection of the cornea, the clear front part of the eye. Symptoms include severe pain, sensitivity to light, tearing, and decreased vision.
Bacterial eye infections are typically treated with antibiotic eye drops or ointments. It is important to seek medical attention promptly if you suspect a bacterial eye infection, as untreated infections can lead to serious complications such as corneal ulcers and vision loss. Preventive measures include good hygiene practices, such as washing your hands frequently and avoiding touching or rubbing your eyes.
Corneal diseases are a group of disorders that affect the cornea, which is the clear, dome-shaped surface at the front of the eye. The cornea plays an important role in focusing vision, and any damage or disease can cause significant visual impairment or loss. Some common types of corneal diseases include:
1. Keratoconus: A progressive disorder in which the cornea thins and bulges outward into a cone shape, causing distorted vision.
2. Fuchs' dystrophy: A genetic disorder that affects the inner layer of the cornea called the endothelium, leading to swelling, cloudiness, and decreased vision.
3. Dry eye syndrome: A condition in which the eyes do not produce enough tears or the tears evaporate too quickly, causing discomfort, redness, and blurred vision.
4. Corneal ulcers: Open sores on the cornea that can be caused by infection, trauma, or other factors.
5. Herpes simplex keratitis: A viral infection of the cornea that can cause recurrent episodes of inflammation, scarring, and vision loss.
6. Corneal dystrophies: Inherited disorders that affect the structure and clarity of the cornea, leading to visual impairment or blindness.
7. Bullous keratopathy: A condition in which the endothelium fails to pump fluid out of the cornea, causing it to swell and form blisters.
8. Corneal trauma: Injury to the cornea caused by foreign objects, chemicals, or other factors that can lead to scarring, infection, and vision loss.
Treatment for corneal diseases varies depending on the specific condition and severity of the disease. Options may include eyedrops, medications, laser surgery, corneal transplantation, or other treatments.
A hydrogel is a biomaterial that is composed of a three-dimensional network of crosslinked polymers, which are able to absorb and retain a significant amount of water or biological fluids while maintaining their structure. Hydrogels are similar to natural tissues in their water content, making them suitable for various medical applications such as contact lenses, wound dressings, drug delivery systems, tissue engineering, and regenerative medicine.
Hydrogels can be synthesized from a variety of materials, including synthetic polymers like polyethylene glycol (PEG) or natural polymers like collagen, hyaluronic acid, or chitosan. The properties of hydrogels, such as their mechanical strength, degradation rate, and biocompatibility, can be tailored to specific applications by adjusting the type and degree of crosslinking, the molecular weight of the polymers, and the addition of functional groups or drugs.
Hydrogels have shown great potential in medical research and clinical practice due to their ability to mimic the natural environment of cells and tissues, provide sustained drug release, and promote tissue regeneration.
A cataract is a clouding of the natural lens in the eye that affects vision. This clouding can cause vision to become blurry, faded, or dim, making it difficult to see clearly. Cataracts are a common age-related condition, but they can also be caused by injury, disease, or medication use. In most cases, cataracts develop gradually over time and can be treated with surgery to remove the cloudy lens and replace it with an artificial one.
Extended-wear contact lenses are a type of contact lens that is designed to be worn continuously, including during sleep, for an extended period of time. These lenses are typically made from materials that allow more oxygen to reach the eye, reducing the risk of eye irritation and infection compared to traditional overnight wear of non-extended wear lenses.
Extended-wear contact lenses can be worn for up to 30 days or longer, depending on the specific lens material and the individual's tolerance. However, it is important to note that even extended-wear contacts come with some risks, including a higher risk of eye infections and corneal ulcers compared to daily wear lenses. Therefore, it is essential to follow the recommended wearing schedule and replacement schedule provided by an eye care professional, as well as to have regular eye exams to monitor the health of the eyes.
The crystalline lens in the eye is composed of three main parts: the capsule, the cortex, and the nucleus. The lens cortex is the outer layer of the lens, located between the capsule and the nucleus. It is made up of proteins and water, and its primary function is to help refract (bend) light rays as they pass through the eye, contributing to the focusing power of the eye.
The cortex is more flexible than the central nucleus, allowing it to change shape and adjust the focus of the eye for different distances. However, with age, the lens cortex can become less elastic, leading to presbyopia, a common age-related condition that affects the ability to focus on close objects. Additionally, changes in the lens cortex have been associated with cataracts, a clouding of the lens that can impair vision.
The crystalline lens of the eye is covered by a transparent, elastic capsule known as the lens capsule. This capsule is made up of collagen and forms the continuous outer layer of the lens. It is highly resistant to both physical and chemical insults, which allows it to protect the lens fibers within. The lens capsule is important for maintaining the shape and transparency of the lens, which are essential for proper focusing of light onto the retina.
Eyeglasses are a medical device used to correct vision problems. Also known as spectacles, they consist of frames that hold one or more lenses through which a person looks to see clearly. The lenses may be made of glass or plastic and are designed to compensate for various visual impairments such as nearsightedness, farsightedness, astigmatism, or presbyopia. Eyeglasses can be custom-made to fit an individual's face and prescription, and they come in a variety of styles, colors, and materials. Some people wear eyeglasses all the time, while others may only need to wear them for certain activities such as reading or driving.
The lens nucleus, also known as the crystalline lens nucleus, is the central part of the crystalline lens in the eye. The crystalline lens is a biconvex structure located behind the iris and pupil, which helps to refract (bend) light rays and focus them onto the retina.
The lens nucleus is composed of densely packed lens fibers that have lost their nuclei and cytoplasm during differentiation. It is surrounded by the lens cortex, which consists of younger lens fiber cells that are still metabolically active. The lens nucleus is relatively avascular and receives its nutrients through diffusion from the aqueous humor in the anterior chamber of the eye.
The lens nucleus plays an important role in the accommodation process, which allows the eye to focus on objects at different distances. During accommodation, the ciliary muscles contract and release tension on the lens zonules, allowing the lens to become thicker and increase its curvature. This results in a decrease in the focal length of the lens and enables the eye to focus on nearby objects. The lens nucleus is more rigid than the cortex and helps maintain the shape of the lens during accommodation.
Changes in the lens nucleus are associated with several age-related eye conditions, including cataracts and presbyopia. Cataracts occur when the lens becomes cloudy or opaque, leading to a decrease in vision clarity. Presbyopia is a condition that affects the ability to focus on near objects and is caused by a hardening of the lens nucleus and a loss of elasticity in the lens fibers.
Ocular refraction is a medical term that refers to the bending of light as it passes through the optical media of the eye, including the cornea and lens. This process allows the eye to focus light onto the retina, creating a clear image. The refractive power of the eye is determined by the curvature and transparency of these structures.
In a normal eye, light rays are bent or refracted in such a way that they converge at a single point on the retina, producing a sharp and focused image. However, if the curvature of the cornea or lens is too steep or too flat, the light rays may not converge properly, resulting in a refractive error such as myopia (nearsightedness), hyperopia (farsightedness), or astigmatism.
Ocular refraction can be measured using a variety of techniques, including retinoscopy, automated refraction, and subjective refraction. These measurements are used to determine the appropriate prescription for corrective lenses such as eyeglasses or contact lenses. In some cases, ocular refractive errors may be corrected surgically through procedures such as LASIK or PRK.
Lens diseases refer to conditions that affect the lens of the eye, which is a transparent structure located behind the iris and pupil. The main function of the lens is to focus light onto the retina, enabling clear vision. Here are some examples of lens diseases:
1. Cataract: A cataract is a clouding of the lens that affects vision. It is a common age-related condition, but can also be caused by injury, disease, or medication.
2. Presbyopia: This is not strictly a "disease," but rather an age-related change in the lens that causes difficulty focusing on close objects. It typically becomes noticeable in people over the age of 40.
3. Lens dislocation: This occurs when the lens slips out of its normal position, usually due to trauma or a genetic disorder. It can cause vision problems and may require surgical intervention.
4. Lens opacity: This refers to any clouding or opacification of the lens that is not severe enough to be considered a cataract. It can cause visual symptoms such as glare or blurred vision.
5. Anterior subcapsular cataract: This is a type of cataract that forms in the front part of the lens, often as a result of injury or inflammation. It can cause significant visual impairment.
6. Posterior subcapsular cataract: This is another type of cataract that forms at the back of the lens, often as a result of diabetes or certain medications. It can also cause significant visual impairment.
Overall, lens diseases can have a significant impact on vision and quality of life, and may require medical intervention to manage or treat.
Disinfection is the process of eliminating or reducing harmful microorganisms from inanimate objects and surfaces through the use of chemicals, heat, or other methods. The goal of disinfection is to reduce the number of pathogens to a level that is considered safe for human health. Disinfection is an important step in preventing the spread of infectious diseases in healthcare settings, food processing facilities, and other environments where there is a risk of infection transmission.
It's important to note that disinfection is not the same as sterilization, which is the complete elimination of all microorganisms, including spores. Disinfection is generally less effective than sterilization but is often sufficient for most non-critical surfaces and objects. The choice between disinfection and sterilization depends on the level of risk associated with the item or surface being treated and the intended use of that item or surface.
Intraocular lens (IOL) implantation is a surgical procedure that involves placing a small artificial lens inside the eye to replace the natural lens that has been removed. This procedure is typically performed during cataract surgery, where the cloudy natural lens is removed and replaced with an IOL to restore clear vision.
During the procedure, a small incision is made in the eye, and the cloudy lens is broken up and removed using ultrasound waves or laser energy. Then, the folded IOL is inserted through the same incision and positioned in the correct place inside the eye. Once in place, the IOL unfolds and is secured into position.
There are several types of IOLs available, including monofocal, multifocal, toric, and accommodating lenses. Monofocal lenses provide clear vision at one distance, while multifocal lenses offer clear vision at multiple distances. Toric lenses correct astigmatism, and accommodating lenses can change shape to focus on objects at different distances.
Overall, intraocular lens implantation is a safe and effective procedure that can help restore clear vision in patients with cataracts or other eye conditions that require the removal of the natural lens.
Hydrogels are defined in the medical and biomedical fields as cross-linked, hydrophilic polymer networks that have the ability to swell and retain a significant amount of water or biological fluids while maintaining their structure. They can be synthesized from natural, synthetic, or hybrid polymers.
Hydrogels are known for their biocompatibility, high water content, and soft consistency, which resemble natural tissues, making them suitable for various medical applications such as contact lenses, drug delivery systems, tissue engineering, wound dressing, and biosensors. The physical and chemical properties of hydrogels can be tailored to specific uses by adjusting the polymer composition, cross-linking density, and network structure.
Fusariosis is a rare but serious invasive fungal infection caused by the Fusarium species, a type of filamentous fungi that are commonly found in the environment, particularly in soil and plants. The infection can affect various organs and tissues, including the lungs, sinuses, skin, nails, and internal organs such as the brain, heart, and kidneys.
Fusariosis is often difficult to diagnose due to its nonspecific symptoms and the challenges of detecting the fungus in clinical samples. The infection can occur in people with weakened immune systems, such as those undergoing chemotherapy, organ transplantation, or treatment with immunosuppressive drugs.
The severity of fusariosis varies depending on the site of infection and the patient's underlying health status. In some cases, it can cause severe illness and even death, especially in patients with prolonged neutropenia (low white blood cell count) or other serious medical conditions. Treatment typically involves antifungal medications, such as voriconazole or amphotericin B, and sometimes surgical debridement of infected tissues.
Myopia, also known as nearsightedness, is a common refractive error of the eye. It occurs when the eye is either too long or the cornea (the clear front part of the eye) is too curved. As a result, light rays focus in front of the retina instead of directly on it, causing distant objects to appear blurry while close objects remain clear.
Myopia typically develops during childhood and can progress gradually or rapidly until early adulthood. It can be corrected with glasses, contact lenses, or refractive surgery such as LASIK. Regular eye examinations are essential for people with myopia to monitor any changes in their prescription and ensure proper correction.
While myopia is generally not a serious condition, high levels of nearsightedness can increase the risk of certain eye diseases, including cataracts, glaucoma, retinal detachment, and myopic degeneration. Therefore, it's crucial to manage myopia effectively and maintain regular follow-ups with an eye care professional.
Visual acuity is a measure of the sharpness or clarity of vision. It is usually tested by reading an eye chart from a specific distance, such as 20 feet (6 meters). The standard eye chart used for this purpose is called the Snellen chart, which contains rows of letters that decrease in size as you read down the chart.
Visual acuity is typically expressed as a fraction, with the numerator representing the testing distance and the denominator indicating the smallest line of type that can be read clearly. For example, if a person can read the line on the eye chart that corresponds to a visual acuity of 20/20, it means they have normal vision at 20 feet. If their visual acuity is 20/40, it means they must be as close as 20 feet to see what someone with normal vision can see at 40 feet.
It's important to note that visual acuity is just one aspect of overall vision and does not necessarily reflect other important factors such as peripheral vision, depth perception, color vision, or contrast sensitivity.
Equipment contamination in a medical context refers to the presence of harmful microorganisms, such as bacteria, viruses, or fungi, on the surfaces of medical equipment or devices. This can occur during use, storage, or transportation of the equipment and can lead to the transmission of infections to patients, healthcare workers, or other individuals who come into contact with the contaminated equipment.
Equipment contamination can occur through various routes, including contact with contaminated body fluids, airborne particles, or environmental surfaces. To prevent equipment contamination and the resulting infection transmission, it is essential to follow strict infection control practices, such as regular cleaning and disinfection of equipment, use of personal protective equipment (PPE), and proper handling and storage of medical devices.
Presbyopia is a age-related eye condition, typically occurring after the age of 40, where the lens of the eye loses its flexibility and makes it difficult to focus on near objects. This results in blurred vision when reading, sewing or focusing on other close-up tasks. It's a natural part of the aging process and is not a disease. Corrective measures such as reading glasses, bifocals, multifocal lenses or contact lenses, or refractive surgery can help manage this condition.
Fluorophotometry is a medical diagnostic technique that measures the concentration of fluorescein dye in various tissues, particularly the eye. This technique utilizes a specialized instrument called a fluorophotometer which emits light at a specific wavelength that causes the fluorescein to emit light at a longer wavelength. The intensity of this emitted light is then measured and used to calculate the concentration of fluorescein in the tissue.
Fluorophotometry is often used in ophthalmology to assess the permeability of the blood-retinal barrier, which can be helpful in diagnosing and monitoring conditions such as diabetic retinopathy, age-related macular degeneration, and uveitis. It may also have applications in other medical fields for measuring the concentration of fluorescent markers in various tissues.
Polyhydroxyethyl Methacrylate (PHEMA) is not a medical term itself, but a chemical compound that is used in various medical and biomedical applications. Therefore, I will provide you with a chemical definition of PHEMA:
Polyhydroxyethyl Methacrylate (PHEMA) is a type of synthetic hydrogel, which is a cross-linked polymer network with the ability to absorb and retain significant amounts of water or biological fluids. It is made by polymerizing the methacrylate monomer, hydroxyethyl methacrylate (HEMA), in the presence of a crosslinking agent. The resulting PHEMA material has excellent biocompatibility, making it suitable for various medical applications such as contact lenses, drug delivery systems, artificial cartilage, and wound dressings.
Astigmatism is a common eye condition that occurs when the cornea or lens has an irregular shape, causing blurred or distorted vision. The cornea and lens are typically smooth and curved uniformly in all directions, allowing light to focus clearly on the retina. However, if the cornea or lens is not smoothly curved and has a steeper curve in one direction than the other, it causes light to focus unevenly on the retina, leading to astigmatism.
Astigmatism can cause blurred vision at all distances, as well as eye strain, headaches, and fatigue. It is often present from birth and can be hereditary, but it can also develop later in life due to eye injuries or surgery. Astigmatism can be corrected with glasses, contact lenses, or refractive surgery such as LASIK.
Fungal eye infections, also known as fungal keratitis or ocular fungal infections, are caused by the invasion of fungi into the eye. The most common types of fungi that cause these infections include Fusarium, Aspergillus, and Candida. These infections can affect any part of the eye, including the cornea, conjunctiva, sclera, and vitreous humor.
Fungal eye infections often present with symptoms such as redness, pain, sensitivity to light, tearing, blurred vision, and discharge. In severe cases, they can lead to corneal ulcers, perforation of the eye, and even blindness if left untreated. Risk factors for fungal eye infections include trauma to the eye, contact lens wear, immunosuppression, and pre-existing eye conditions such as dry eye or previous eye surgery.
Diagnosis of fungal eye infections typically involves a thorough eye examination, including visual acuity testing, slit lamp examination, and sometimes corneal scrapings for microbiological culture and sensitivity testing. Treatment usually involves topical antifungal medications, such as natamycin or amphotericin B, and in some cases may require oral or intravenous antifungal therapy. In severe cases, surgical intervention may be necessary to remove infected tissue or repair any damage caused by the infection.
Crystallins are the major proteins found in the lens of the eye in vertebrates. They make up about 90% of the protein content in the lens and are responsible for maintaining the transparency and refractive properties of the lens, which are essential for clear vision. There are two main types of crystallins, alpha (α) and beta/gamma (β/γ), which are further divided into several subtypes. These proteins are highly stable and have a long half-life, which allows them to remain in the lens for an extended period of time. Mutations in crystallin genes have been associated with various eye disorders, including cataracts and certain types of glaucoma.
Methyl Methacrylates (MMA) are a family of synthetic materials that are commonly used in the medical field, particularly in orthopedic and dental applications. Medically, MMA is often used as a bone cement to fix prosthetic implants, such as artificial hips or knees, into place during surgeries.
Methyl methacrylates consist of a type of acrylic resin that hardens when mixed with a liquid catalyst. This property allows it to be easily molded and shaped before it sets, making it ideal for use in surgical procedures where precise positioning is required. Once hardened, MMA forms a strong, stable bond with the bone, helping to secure the implant in place.
It's important to note that while MMA is widely used in medical applications, there have been concerns about its safety in certain situations. For example, some studies have suggested that high levels of methyl methacrylate fumes released during the setting process may be harmful to both patients and surgical staff. Therefore, appropriate precautions should be taken when using MMA-based products in medical settings.
The corneal epithelium is the outermost layer of the cornea, which is the clear, dome-shaped surface at the front of the eye. It is a stratified squamous epithelium, consisting of several layers of flat, scale-like cells that are tightly packed together. The corneal epithelium serves as a barrier to protect the eye from microorganisms, dust, and other foreign particles. It also provides a smooth surface for the refraction of light, contributes to the maintenance of corneal transparency, and plays a role in the eye's sensitivity to touch and pain. The corneal epithelium is constantly being renewed through the process of cell division and shedding, with new cells produced by stem cells located at the limbus, the border between the cornea and the conjunctiva.
Eyelids are the thin folds of skin that cover and protect the front surface (cornea) of the eye when closed. They are composed of several layers, including the skin, muscle, connective tissue, and a mucous membrane called the conjunctiva. The upper and lower eyelids meet at the outer corner of the eye (lateral canthus) and the inner corner of the eye (medial canthus).
The main function of the eyelids is to protect the eye from foreign particles, light, and trauma. They also help to distribute tears evenly over the surface of the eye through blinking, which helps to keep the eye moist and healthy. Additionally, the eyelids play a role in facial expressions and non-verbal communication.
Lens subluxation, also known as lens dislocation or ectopia lentis, is a condition where the lens of the eye becomes partially or completely displaced from its normal position. The lens is held in place by tiny fibers called zonules, which can become weakened or broken due to various reasons such as genetic disorders (like Marfan syndrome, homocystinuria, and Weill-Marchesani syndrome), trauma, inflammation, or cataract surgery complications. This displacement can lead to symptoms like blurry vision, double vision, sensitivity to light, or the appearance of a shadow in the peripheral vision. In some cases, lens subluxation may not cause any noticeable symptoms and can be discovered during routine eye examinations. Treatment options depend on the severity and underlying cause of the subluxation and may include eyeglasses, contact lenses, or surgical intervention to remove and replace the displaced lens with an intraocular lens (IOL).
Refractive errors are a group of vision conditions that include nearsightedness (myopia), farsightedness (hyperopia), astigmatism, and presbyopia. These conditions occur when the shape of the eye prevents light from focusing directly on the retina, causing blurred or distorted vision.
Myopia is a condition where distant objects appear blurry while close-up objects are clear. This occurs when the eye is too long or the cornea is too curved, causing light to focus in front of the retina instead of directly on it.
Hyperopia, on the other hand, is a condition where close-up objects appear blurry while distant objects are clear. This happens when the eye is too short or the cornea is not curved enough, causing light to focus behind the retina.
Astigmatism is a condition that causes blurred vision at all distances due to an irregularly shaped cornea or lens.
Presbyopia is a natural aging process that affects everyone as they get older, usually around the age of 40. It causes difficulty focusing on close-up objects and can be corrected with reading glasses, bifocals, or progressive lenses.
Refractive errors can be diagnosed through a comprehensive eye exam and are typically corrected with eyeglasses, contact lenses, or refractive surgery such as LASIK.
Disinfectants are antimicrobial agents that are applied to non-living objects to destroy or irreversibly inactivate microorganisms, but not necessarily their spores. They are different from sterilizers, which kill all forms of life, and from antiseptics, which are used on living tissue. Disinfectants work by damaging the cell wall or membrane of the microorganism, disrupting its metabolism, or interfering with its ability to reproduce. Examples of disinfectants include alcohol, bleach, hydrogen peroxide, and quaternary ammonium compounds. They are commonly used in hospitals, laboratories, and other settings where the elimination of microorganisms is important for infection control. It's important to use disinfectants according to the manufacturer's instructions, as improper use can reduce their effectiveness or even increase the risk of infection.
Eye infections, also known as ocular infections, are conditions characterized by the invasion and multiplication of pathogenic microorganisms in any part of the eye or its surrounding structures. These infections can affect various parts of the eye, including the conjunctiva (conjunctivitis), cornea (keratitis), eyelid (blepharitis), or the internal structures of the eye (endophthalmitis, uveitis). The symptoms may include redness, pain, discharge, itching, blurred vision, and sensitivity to light. The cause can be bacterial, viral, fungal, or parasitic, and the treatment typically involves antibiotics, antivirals, or antifungals, depending on the underlying cause.
The corneal stroma, also known as the substantia propria, is the thickest layer of the cornea, which is the clear, dome-shaped surface at the front of the eye. The cornea plays a crucial role in focusing vision.
The corneal stroma makes up about 90% of the cornea's thickness and is composed of parallel bundles of collagen fibers that are arranged in regular, repeating patterns. These fibers give the cornea its strength and transparency. The corneal stroma also contains a small number of cells called keratocytes, which produce and maintain the collagen fibers.
Disorders that affect the corneal stroma can cause vision loss or other eye problems. For example, conditions such as keratoconus, in which the cornea becomes thin and bulges outward, can distort vision and make it difficult to see clearly. Other conditions, such as corneal scarring or infection, can also affect the corneal stroma and lead to vision loss or other eye problems.
The eye is the organ of sight, primarily responsible for detecting and focusing on visual stimuli. It is a complex structure composed of various parts that work together to enable vision. Here are some of the main components of the eye:
1. Cornea: The clear front part of the eye that refracts light entering the eye and protects the eye from harmful particles and microorganisms.
2. Iris: The colored part of the eye that controls the amount of light reaching the retina by adjusting the size of the pupil.
3. Pupil: The opening in the center of the iris that allows light to enter the eye.
4. Lens: A biconvex structure located behind the iris that further refracts light and focuses it onto the retina.
5. Retina: A layer of light-sensitive cells (rods and cones) at the back of the eye that convert light into electrical signals, which are then transmitted to the brain via the optic nerve.
6. Optic Nerve: The nerve that carries visual information from the retina to the brain.
7. Vitreous: A clear, gel-like substance that fills the space between the lens and the retina, providing structural support to the eye.
8. Conjunctiva: A thin, transparent membrane that covers the front of the eye and the inner surface of the eyelids.
9. Extraocular Muscles: Six muscles that control the movement of the eye, allowing for proper alignment and focus.
The eye is a remarkable organ that allows us to perceive and interact with our surroundings. Various medical specialties, such as ophthalmology and optometry, are dedicated to the diagnosis, treatment, and management of various eye conditions and diseases.
Orthokeratology, often referred to as "ortho-k," is a non-surgical procedure that uses specially designed contact lenses to temporarily reshape the cornea (the clear, dome-shaped surface at the front of the eye). The goal of orthokeratology is to flatten the cornea slightly so that it can properly focus light onto the retina and improve vision.
During an orthokeratology procedure, a patient wears specially fitted contact lenses while they sleep. These lenses gently reshape the cornea overnight, allowing the patient to see clearly during the day without needing glasses or contact lenses. The effects of orthokeratology are usually reversible and may wear off if the patient stops wearing the contact lenses regularly.
Orthokeratology is often used as an alternative to refractive surgery for people who want to correct their vision without undergoing a surgical procedure. It can be particularly useful for individuals with mild to moderate myopia (nearsightedness) and astigmatism, although it may also be used to treat other refractive errors.
It's important to note that orthokeratology is not a permanent solution for vision problems, and it does carry some risks, such as eye infections and corneal abrasions. As with any medical procedure, it's essential to consult with an eye care professional to determine whether orthokeratology is the right choice for you.
Hygiene is the science and practice of maintaining and promoting health and preventing disease through cleanliness in personal and public environments. It includes various measures such as handwashing, bathing, using clean clothes, cleaning and disinfecting surfaces, proper waste disposal, safe food handling, and managing water supplies to prevent the spread of infectious agents like bacteria, viruses, and parasites.
In a medical context, hygiene is crucial in healthcare settings to prevent healthcare-associated infections (HAIs) and ensure patient safety. Healthcare professionals are trained in infection control practices, including proper hand hygiene, use of personal protective equipment (PPE), environmental cleaning and disinfection, and safe injection practices.
Overall, maintaining good hygiene is essential for overall health and well-being, reducing the risk of illness and promoting a healthy lifestyle.
Silicone elastomers are a type of synthetic rubber made from silicone, which is a polymer composed primarily of silicon-oxygen bonds. They are known for their durability, flexibility, and resistance to heat, cold, and moisture. Silicone elastomers can be manufactured in various forms, including liquids, gels, and solids, and they are used in a wide range of medical applications such as:
1. Breast implants: Silicone elastomer shells filled with silicone gel are commonly used for breast augmentation and reconstruction.
2. Contact lenses: Some contact lenses are made from silicone elastomers due to their high oxygen permeability, which allows for better eye health.
3. Catheters: Silicone elastomer catheters are flexible and resistant to kinking, making them suitable for long-term use in various medical procedures.
4. Implantable drug delivery systems: Silicone elastomers can be used as a matrix for controlled release of drugs, allowing for sustained and targeted medication administration.
5. Medical adhesives: Silicone elastomer adhesives are biocompatible and can be used to attach medical devices to the skin or other tissues.
6. Sealants and coatings: Silicone elastomers can be used as sealants and coatings in medical devices to prevent leakage, improve durability, and reduce infection risk.
It is important to note that while silicone elastomers are generally considered safe for medical use, there have been concerns about the potential health risks associated with breast implants, such as capsular contracture, breast pain, and immune system reactions. However, these risks vary depending on the individual's health status and the specific type of silicone elastomer used.
Ophthalmic solutions are sterile, single-use or multi-dose preparations in a liquid form that are intended for topical administration to the eye. These solutions can contain various types of medications, such as antibiotics, anti-inflammatory agents, antihistamines, or lubricants, which are used to treat or prevent ocular diseases and conditions.
The pH and osmolarity of ophthalmic solutions are carefully controlled to match the physiological environment of the eye and minimize any potential discomfort or irritation. The solutions may be packaged in various forms, including drops, sprays, or irrigations, depending on the intended use and administration route.
It is important to follow the instructions for use provided by a healthcare professional when administering ophthalmic solutions, as improper use can lead to eye injury or reduced effectiveness of the medication.
Dry eye syndrome, also known as keratoconjunctivitis sicca, is a condition characterized by insufficient lubrication and moisture of the eyes. This occurs when the tears produced by the eyes are not sufficient in quantity or quality to keep the eyes moist and comfortable. The medical definition of dry eye syndromes includes the following symptoms:
1. A gritty or sandy sensation in the eyes
2. Burning or stinging sensations
3. Redness and irritation
4. Blurred vision that improves with blinking
5. Light sensitivity
6. A feeling of something foreign in the eye
7. Stringy mucus in or around the eyes
8. Difficulty wearing contact lenses
9. Watery eyes, which may seem contradictory but can be a response to dryness
10. Eye fatigue and discomfort after prolonged screen time or reading
The causes of dry eye syndromes can include aging, hormonal changes, certain medical conditions (such as diabetes, rheumatoid arthritis, lupus, Sjogren's syndrome), medications (antihistamines, decongestants, antidepressants, birth control pills), environmental factors (dry air, wind, smoke, dust), and prolonged screen time or reading.
Treatment for dry eye syndromes depends on the severity of the condition and its underlying causes. It may include artificial tears, lifestyle changes, prescription medications, and in some cases, surgical procedures to improve tear production or drainage.
Eye diseases are a range of conditions that affect the eye or visual system, causing damage to vision and, in some cases, leading to blindness. These diseases can be categorized into various types, including:
1. Refractive errors: These include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia, which affect the way light is focused on the retina and can usually be corrected with glasses or contact lenses.
2. Cataracts: A clouding of the lens inside the eye that leads to blurry vision, glare, and decreased contrast sensitivity. Cataract surgery is the most common treatment for this condition.
3. Glaucoma: A group of diseases characterized by increased pressure in the eye, leading to damage to the optic nerve and potential blindness if left untreated. Treatment includes medications, laser therapy, or surgery.
4. Age-related macular degeneration (AMD): A progressive condition that affects the central part of the retina called the macula, causing blurry vision and, in advanced stages, loss of central vision. Treatment may include anti-VEGF injections, laser therapy, or nutritional supplements.
5. Diabetic retinopathy: A complication of diabetes that affects the blood vessels in the retina, leading to bleeding, leakage, and potential blindness if left untreated. Treatment includes laser therapy, anti-VEGF injections, or surgery.
6. Retinal detachment: A separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly with surgery.
7. Amblyopia (lazy eye): A condition where one eye does not develop normal vision, often due to a misalignment or refractive error in childhood. Treatment includes correcting the underlying problem and encouraging the use of the weaker eye through patching or other methods.
8. Strabismus (crossed eyes): A misalignment of the eyes that can lead to amblyopia if not treated promptly with surgery, glasses, or other methods.
9. Corneal diseases: Conditions that affect the transparent outer layer of the eye, such as keratoconus, Fuchs' dystrophy, and infectious keratitis, which can lead to vision loss if not treated promptly.
10. Uveitis: Inflammation of the middle layer of the eye, which can cause vision loss if not treated promptly with anti-inflammatory medications or surgery.
Hyperopia, also known as farsightedness, is a refractive error in which the eye does not focus light directly on the retina when looking at a distant object. Instead, light is focused behind the retina, causing close-up objects to appear blurry. This condition usually results from the eyeball being too short or the cornea having too little curvature. It can be corrected with eyeglasses, contact lenses, or refractive surgery.
The endothelium of the cornea is the thin, innermost layer of cells that lines the inner surface of the cornea, which is the clear, dome-shaped structure at the front of the eye. This single layer of specialized cells is essential for maintaining the transparency and proper hydration of the cornea, allowing light to pass through it and focus on the retina.
The endothelial cells are hexagonal in shape and have tight junctions between them, creating a semi-permeable barrier that controls the movement of water and solutes between the corneal stroma (the middle layer of the cornea) and the anterior chamber (the space between the cornea and the iris). The endothelial cells actively pump excess fluid out of the cornea, maintaining a delicate balance of hydration that is critical for corneal clarity.
Damage to or dysfunction of the corneal endothelium can result in corneal edema (swelling), cloudiness, and loss of vision. Factors contributing to endothelial damage include aging, eye trauma, intraocular surgery, and certain diseases such as Fuchs' dystrophy and glaucoma.
Contact tracing is a key public health strategy used to control the spread of infectious diseases. It involves identifying and monitoring individuals (contacts) who have come into close contact with an infected person (case), to prevent further transmission of the disease. The process typically includes:
1. Case identification: Identifying and confirming cases of infection through diagnostic testing.
2. Contact identification: Finding people who may have been in close contact with the infected case during their infectious period, which is the time when they can transmit the infection to others. Close contacts are usually defined as individuals who have had face-to-face contact with a confirmed case within a certain distance (often 6 feet or closer) and/or shared confined spaces for prolonged periods (usually more than 15 minutes).
3. Contact listing: Recording the identified contacts' information, including their names, addresses, phone numbers, and potentially other demographic data.
4. Risk assessment: Evaluating the level of risk associated with each contact based on factors such as the type of exposure, duration of contact, and the infectiousness of the case.
5. Notification: Informing contacts about their potential exposure to the infection and providing them with necessary health information, education, and guidance. This may include recommendations for self-quarantine, symptom monitoring, testing, and vaccination if available.
6. Follow-up: Monitoring and supporting contacts during their quarantine or isolation period, which typically lasts 14 days from the last exposure to the case. Public health professionals will check in with contacts regularly to assess their symptoms, provide additional guidance, and ensure they are adhering to the recommended infection prevention measures.
7. Data management: Documenting and reporting contact tracing activities for public health surveillance, evaluation, and future planning purposes.
Contact tracing is a critical component of infectious disease control and has been used effectively in managing various outbreaks, including tuberculosis, HIV/AIDS, Ebola, and more recently, COVID-19.
Interferometry is not specifically a medical term, but it is used in certain medical fields such as ophthalmology and optics research. Here is a general definition:
Interferometry is a physical method that uses the interference of waves to measure the differences in phase between two or more waves. In other words, it's a technique that combines two or more light waves to create an interference pattern, which can then be analyzed to extract information about the properties of the light waves, such as their wavelength, amplitude, and phase.
In ophthalmology, interferometry is used in devices like wavefront sensors to measure the aberrations in the eye's optical system. By analyzing the interference pattern created by the light passing through the eye, these devices can provide detailed information about the shape and curvature of the cornea and lens, helping doctors to diagnose and treat various vision disorders.
In optics research, interferometry is used to study the properties of light waves and materials that interact with them. By analyzing the interference patterns created by light passing through different materials or devices, researchers can gain insights into their optical properties, such as their refractive index, thickness, and surface roughness.
The conjunctiva is the mucous membrane that lines the inner surface of the eyelids and covers the front part of the eye, also known as the sclera. It helps to keep the eye moist and protected from irritants. The conjunctiva can become inflamed or infected, leading to conditions such as conjunctivitis (pink eye).
Cataract extraction is a surgical procedure that involves removing the cloudy lens (cataract) from the eye. This procedure is typically performed to restore vision impairment caused by cataracts and improve overall quality of life. There are two primary methods for cataract extraction:
1. Phacoemulsification: This is the most common method used today. It involves making a small incision in the front part of the eye (cornea), inserting an ultrasonic probe to break up the cloudy lens into tiny pieces, and then removing those pieces with suction. After removing the cataract, an artificial intraocular lens (IOL) is inserted to replace the natural lens and help focus light onto the retina.
2. Extracapsular Cataract Extraction: In this method, a larger incision is made on the side of the cornea, allowing the surgeon to remove the cloudy lens in one piece without breaking it up. The back part of the lens capsule is left intact to support the IOL. This technique is less common and typically reserved for more advanced cataracts or when phacoemulsification cannot be performed.
Recovery from cataract extraction usually involves using eye drops to prevent infection and inflammation, as well as protecting the eye with a shield or glasses during sleep for a few weeks after surgery. Most people experience improved vision within a few days to a week following the procedure.
Ocular accommodation is the process by which the eye changes optical power to maintain a clear image or focus on an object as its distance varies. This is primarily achieved by the lens of the eye changing shape through the action of the ciliary muscles inside the eye. When you look at something far away, the lens becomes flatter, and when you look at something close up, the lens thickens. This ability to adjust focus allows for clear vision at different distances.
Eye proteins, also known as ocular proteins, are specific proteins that are found within the eye and play crucial roles in maintaining proper eye function and health. These proteins can be found in various parts of the eye, including the cornea, iris, lens, retina, and other structures. They perform a wide range of functions, such as:
1. Structural support: Proteins like collagen and elastin provide strength and flexibility to the eye's tissues, enabling them to maintain their shape and withstand mechanical stress.
2. Light absorption and transmission: Proteins like opsins and crystallins are involved in capturing and transmitting light signals within the eye, which is essential for vision.
3. Protection against damage: Some eye proteins, such as antioxidant enzymes and heat shock proteins, help protect the eye from oxidative stress, UV radiation, and other environmental factors that can cause damage.
4. Regulation of eye growth and development: Various growth factors and signaling molecules, which are protein-based, contribute to the proper growth, differentiation, and maintenance of eye tissues during embryonic development and throughout adulthood.
5. Immune defense: Proteins involved in the immune response, such as complement components and immunoglobulins, help protect the eye from infection and inflammation.
6. Maintenance of transparency: Crystallin proteins in the lens maintain its transparency, allowing light to pass through unobstructed for clear vision.
7. Neuroprotection: Certain eye proteins, like brain-derived neurotrophic factor (BDNF), support the survival and function of neurons within the retina, helping to preserve vision.
Dysfunction or damage to these eye proteins can contribute to various eye disorders and diseases, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy, and others.
Corneal transplantation, also known as keratoplasty, is a surgical procedure in which all or part of a damaged or diseased cornea is replaced with healthy corneal tissue from a deceased donor. The cornea is the clear, dome-shaped surface at the front of the eye that plays an important role in focusing vision. When it becomes cloudy or misshapen due to injury, infection, or inherited conditions, vision can become significantly impaired.
During the procedure, the surgeon carefully removes a circular section of the damaged cornea and replaces it with a similarly sized piece of donor tissue. The new cornea is then stitched into place using very fine sutures that are typically removed several months after surgery.
Corneal transplantation has a high success rate, with more than 90% of procedures resulting in improved vision. However, as with any surgical procedure, there are risks involved, including infection, rejection of the donor tissue, and bleeding. Regular follow-up care is essential to monitor for any signs of complications and ensure proper healing.
Amebiasis is defined as an infection caused by the protozoan parasite Entamoeba histolytica, which can affect the intestines and other organs. The infection can range from asymptomatic to symptomatic with various manifestations such as abdominal pain, diarrhea (which may be mild or severe), bloody stools, and fever. In some cases, it can lead to serious complications like liver abscess. Transmission of the parasite typically occurs through the ingestion of contaminated food or water.
Contact dermatitis is a type of inflammation of the skin that occurs when it comes into contact with a substance that the individual has developed an allergic reaction to or that causes irritation. It can be divided into two main types: allergic contact dermatitis and irritant contact dermatitis.
Allergic contact dermatitis is caused by an immune system response to a substance, known as an allergen, which the individual has become sensitized to. When the skin comes into contact with this allergen, it triggers an immune reaction that results in inflammation and characteristic symptoms such as redness, swelling, itching, and blistering. Common allergens include metals (such as nickel), rubber, medications, fragrances, and cosmetics.
Irritant contact dermatitis, on the other hand, is caused by direct damage to the skin from a substance that is inherently irritating or corrosive. This can occur after exposure to strong acids, alkalis, solvents, or even prolonged exposure to milder irritants like water or soap. Symptoms of irritant contact dermatitis include redness, pain, burning, and dryness at the site of contact.
The treatment for contact dermatitis typically involves avoiding further exposure to the allergen or irritant, as well as managing symptoms with topical corticosteroids, antihistamines, or other medications as needed. In some cases, patch testing may be performed to identify specific allergens that are causing the reaction.
Ophthalmodynamometry is a medical technique used to measure the amount of pressure or force required to flatten the cornea, which can help in the diagnosis and evaluation of various eye conditions, particularly glaucoma. It involves using a handheld device called an ophthalmodynamometer to apply gentle pressure to the eyelid while observing changes in the optic nerve head and retinal vessels through an ophthalmoscope. The test provides information about the resistance of the eyeball to external pressure, which can be useful in assessing the functioning of the eye's aqueous humor drainage system and identifying any abnormalities that may contribute to increased intraocular pressure (IOP).
The procedure typically involves several steps:
1. The patient is asked to look in different directions while the examiner observes the optic nerve head and retinal vessels through an ophthalmoscope.
2. The examiner then applies gentle pressure to the eyelid using the ophthalmodynamometer, gradually increasing the force until the cornea begins to flatten.
3. The amount of pressure required to achieve this is recorded as the ophthalmodynamometric value.
4. The examiner may repeat the process several times to ensure accurate and consistent results.
5. The results are then compared with normative data to determine whether the patient's IOP is within normal limits or if there are any signs of glaucoma or other eye conditions.
It is important to note that ophthalmodynamometry should only be performed by trained healthcare professionals, as improper technique can lead to inaccurate results and potential harm to the patient's eyes.
Equipment design, in the medical context, refers to the process of creating and developing medical equipment and devices, such as surgical instruments, diagnostic machines, or assistive technologies. This process involves several stages, including:
1. Identifying user needs and requirements
2. Concept development and brainstorming
3. Prototyping and testing
4. Design for manufacturing and assembly
5. Safety and regulatory compliance
6. Verification and validation
7. Training and support
The goal of equipment design is to create safe, effective, and efficient medical devices that meet the needs of healthcare providers and patients while complying with relevant regulations and standards. The design process typically involves a multidisciplinary team of engineers, clinicians, designers, and researchers who work together to develop innovative solutions that improve patient care and outcomes.
Biguanides are a class of oral hypoglycemic agents used in the treatment of type 2 diabetes. The primary mechanism of action of biguanides is to decrease hepatic glucose production and increase insulin sensitivity, which leads to reduced fasting glucose levels and improved glycemic control.
The most commonly prescribed biguanide is metformin, which has been widely used for several decades due to its efficacy and low risk of hypoglycemia. Other biguanides include phenformin and buformin, but these are rarely used due to their association with a higher risk of lactic acidosis, a potentially life-threatening complication.
In addition to their glucose-lowering effects, biguanides have also been shown to have potential benefits on cardiovascular health and weight management, making them a valuable treatment option for many individuals with type 2 diabetes. However, they should be used with caution in patients with impaired renal function or other underlying medical conditions that may increase the risk of lactic acidosis.
Serratia infections are caused by bacteria named Serratia marcescens, which belongs to the family Enterobacteriaceae. These gram-negative, facultatively anaerobic bacilli can be found in various environments, including water, soil, and food. While they are a part of the normal gut flora in humans and animals, Serratia species can cause infections under certain circumstances, such as impaired immune function or when introduced into sterile sites like the bloodstream, urinary tract, or lungs.
Serratia infections can manifest as:
1. Pneumonia: A lower respiratory tract infection that causes cough, chest pain, and difficulty breathing.
2. Urinary Tract Infections (UTIs): Bacterial invasion of the urinary system, leading to symptoms like dysuria, frequency, urgency, and cloudy or foul-smelling urine.
3. Bloodstream infections (Bacteremia/Septicemia): Invasion of the bloodstream by Serratia species, which can result in fever, chills, and sepsis.
4. Wound infections: Localized infection of wounds or surgical sites, causing pain, redness, swelling, and pus discharge.
5. Eye infections (Conjunctivitis/Keratitis): Bacterial invasion of the eye, leading to symptoms like redness, pain, tearing, and discharge.
6. Central Nervous System (CNS) infections: Rare but severe complications include meningitis or brain abscesses.
Serratia infections can be challenging to treat due to their resistance to multiple antibiotics, including first-line agents like ampicillin and cephalosporins. Therefore, healthcare providers often rely on carbapenems, fluoroquinolones, or aminoglycosides for treatment. Prompt diagnosis and appropriate antimicrobial therapy are crucial to ensure favorable outcomes in patients with Serratia infections.
I'm sorry for any confusion, but "Optics and Photonics" is a broad field that encompasses various scientific and engineering disciplines. It doesn't have a specific medical definition, as it's not a term typically used in a medical context.
However, I can provide a general definition:
Optics is the study of light and its interactions with matter. This includes how light is produced, controlled, transmitted, and detected. It involves phenomena such as reflection, refraction, diffraction, and interference.
Photonics, on the other hand, is a branch of optics that deals with the generation, detection, and manipulation of individual photons, the basic units of light. Photonics is often applied to technologies such as lasers, fiber optics, and optical communications.
In a medical context, these fields might be used in various diagnostic and therapeutic applications, such as endoscopes, ophthalmic devices, laser surgery, and imaging technologies like MRI and CT scans. But the terms "Optics" and "Photonics" themselves are not medical conditions or treatments.
Pseudophakia is a medical term that refers to the condition where a person's natural lens in the eye has been replaced with an artificial one. This procedure is typically performed during cataract surgery, where the cloudy, natural lens is removed and replaced with a clear, artificial lens to improve vision. The prefix "pseudo" means false or fake, and "phakia" refers to the natural lens of the eye, hence the term "Pseudophakia" implies a false or artificial lens.
Penetrating keratoplasty (PK) is a type of corneal transplant surgery where the entire thickness of the host's damaged or diseased cornea is removed and replaced with a similar full-thickness portion of a healthy donor's cornea. The procedure aims to restore visual function, alleviate pain, and improve the structural integrity of the eye. It is typically performed for conditions such as severe keratoconus, corneal scarring, or corneal ulcers that cannot be treated with other, less invasive methods. Following the surgery, patients may require extended recovery time and rigorous postoperative care to minimize the risk of complications and ensure optimal visual outcomes.
Allergic contact dermatitis is a type of inflammatory skin reaction that occurs when the skin comes into contact with a substance (allergen) that the immune system recognizes as foreign and triggers an allergic response. This condition is characterized by redness, itching, swelling, blistering, and cracking of the skin, which usually develops within 24-48 hours after exposure to the allergen. Common allergens include metals (such as nickel), rubber, medications, fragrances, and cosmetics. It is important to note that a person must first be sensitized to the allergen before developing an allergic response upon subsequent exposures.
Ophthalmology is a branch of medicine that deals with the diagnosis, treatment, and prevention of diseases and disorders of the eye and visual system. It is a surgical specialty, and ophthalmologists are medical doctors who complete additional years of training to become experts in eye care. They are qualified to perform eye exams, diagnose and treat eye diseases, prescribe glasses and contact lenses, and perform eye surgery. Some subspecialties within ophthalmology include cornea and external disease, glaucoma, neuro-ophthalmology, pediatric ophthalmology, retina and vitreous, and oculoplastics.
Radiation protection, also known as radiation safety, is a field of study and practice that aims to protect people and the environment from harmful effects of ionizing radiation. It involves various measures and techniques used to minimize or eliminate exposure to ionizing radiation, such as:
1. Time: Reducing the amount of time spent near a radiation source.
2. Distance: Increasing the distance between oneself and a radiation source.
3. Shielding: Using materials that can absorb or block radiation to reduce exposure.
4. Containment: Preventing the release of radiation into the environment.
5. Training and education: Providing information and training to individuals who work with radiation sources.
6. Dosimetry and monitoring: Measuring and monitoring radiation doses received by individuals and populations.
7. Emergency planning and response: Developing plans and procedures for responding to radiation emergencies or accidents.
Radiation protection is an important consideration in various fields, including medicine, nuclear energy, research, and manufacturing, where ionizing radiation sources are used or produced.
Methacrylates are a group of chemical compounds that contain the methacrylate functional group, which is a vinyl group (CH2=CH-) with a carbonyl group (C=O) at the β-position. This structure gives them unique chemical and physical properties, such as low viscosity, high reactivity, and resistance to heat and chemicals.
In medical terms, methacrylates are used in various biomedical applications, such as dental restorative materials, bone cements, and drug delivery systems. For example, methacrylate-based resins are commonly used in dentistry for fillings, crowns, and bridges due to their excellent mechanical properties and adhesion to tooth structures.
However, there have been concerns about the potential toxicity of methacrylates, particularly their ability to release monomers that can cause allergic reactions, irritation, or even mutagenic effects in some individuals. Therefore, it is essential to use these materials with caution and follow proper handling and safety protocols.
An excimer laser is a type of laser that is used in various medical procedures, particularly in ophthalmology and dermatology. The term "excimer" is derived from "excited dimer," which refers to a short-lived molecule formed when two atoms combine in an excited state.
Excimer lasers emit light at a specific wavelength that is determined by the type of gas used in the laser. In medical applications, excimer lasers typically use noble gases such as argon, krypton, or xenon, combined with halogens such as fluorine or chlorine. The most commonly used excimer laser in medical procedures is the excimer laser that uses a mixture of argon and fluoride gas to produce light at a wavelength of 193 nanometers (nm).
In ophthalmology, excimer lasers are primarily used for refractive surgery, such as LASIK and PRK, to correct vision problems like myopia, hyperopia, and astigmatism. The laser works by vaporizing tiny amounts of tissue from the cornea, reshaping its curvature to improve the way light is focused onto the retina.
In dermatology, excimer lasers are used for various skin conditions, including psoriasis, vitiligo, and atopic dermatitis. The laser works by emitting high-energy ultraviolet (UV) light that selectively targets and destroys the abnormal cells responsible for these conditions while leaving surrounding healthy tissue intact.
Excimer lasers are known for their precision, accuracy, and minimal side effects, making them a popular choice in medical procedures where fine detail and tissue preservation are critical.
"Pseudomonas aeruginosa" is a medically important, gram-negative, rod-shaped bacterium that is widely found in the environment, such as in soil, water, and on plants. It's an opportunistic pathogen, meaning it usually doesn't cause infection in healthy individuals but can cause severe and sometimes life-threatening infections in people with weakened immune systems, burns, or chronic lung diseases like cystic fibrosis.
P. aeruginosa is known for its remarkable ability to resist many antibiotics and disinfectants due to its intrinsic resistance mechanisms and the acquisition of additional resistance determinants. It can cause various types of infections, including respiratory tract infections, urinary tract infections, gastrointestinal infections, dermatitis, and severe bloodstream infections known as sepsis.
The bacterium produces a variety of virulence factors that contribute to its pathogenicity, such as exotoxins, proteases, and pigments like pyocyanin and pyoverdine, which aid in iron acquisition and help the organism evade host immune responses. Effective infection control measures, appropriate use of antibiotics, and close monitoring of high-risk patients are crucial for managing P. aeruginosa infections.
Conjunctivitis is an inflammation or infection of the conjunctiva, a thin, clear membrane that covers the inner surface of the eyelids and the outer surface of the eye. The condition can cause redness, itching, burning, tearing, discomfort, and a gritty feeling in the eyes. It can also result in a discharge that can be clear, yellow, or greenish.
Conjunctivitis can have various causes, including bacterial or viral infections, allergies, irritants (such as smoke, chlorine, or contact lens solutions), and underlying medical conditions (like dry eye or autoimmune disorders). Treatment depends on the cause of the condition but may include antibiotics, antihistamines, anti-inflammatory medications, or warm compresses.
It is essential to maintain good hygiene practices, like washing hands frequently and avoiding touching or rubbing the eyes, to prevent spreading conjunctivitis to others. If you suspect you have conjunctivitis, it's recommended that you consult an eye care professional for a proper diagnosis and treatment plan.
'Acanthamoeba castellanii' is a species of free-living amoebae that are widely found in the environment, such as in water, soil, and air. These amoebae are known for their ability to survive under various conditions and can cause opportunistic infections in humans, particularly in individuals with weakened immune systems.
'Acanthamoeba castellanii' is known to be associated with a range of diseases, including Acanthamoeba keratitis, a sight-threatening eye infection that primarily affects contact lens wearers, and granulomatous amoebic encephalitis, a rare but serious central nervous system infection.
It is important to note that while 'Acanthamoeba castellanii' can cause infections in humans, these cases are relatively uncommon and typically occur in individuals with compromised immune systems or those who come into contact with contaminated water or soil. Proper hygiene practices and the use of sterile solutions when handling contact lenses can help reduce the risk of infection.
Amebicides are medications that are used to treat infections caused by amebae, which are single-celled microorganisms. One common ameba that can cause infection in humans is Entamoeba histolytica, which can lead to a condition called amebiasis. Amebicides work by killing or inhibiting the growth of the amebae. Some examples of amebicides include metronidazole, tinidazole, and chloroquine. It's important to note that these medications should only be used under the guidance of a healthcare professional, as they can have side effects and may interact with other medications.
Fluorescein is not a medical condition or term, but rather a diagnostic dye used in various medical tests and procedures. Medically, it is referred to as Fluorescein Sodium, a fluorescent compound that absorbs light at one wavelength and emits light at another longer wavelength when excited.
In the field of ophthalmology (eye care), Fluorescein is commonly used in:
1. Fluorescein angiography: A diagnostic test to examine blood flow in the retina and choroid, often used to diagnose and manage conditions like diabetic retinopathy, age-related macular degeneration, and retinal vessel occlusions.
2. Tear film assessment: Fluorescein dye is used to evaluate the quality of tear film and diagnose dry eye syndrome by observing the staining pattern on the cornea.
3. Corneal abrasions/foreign body detection: Fluorescein dye can help identify corneal injuries, such as abrasions or foreign bodies, under a cobalt blue light.
In other medical fields, fluorescein is also used in procedures like:
1. Urinary tract imaging: To detect urinary tract abnormalities and evaluate kidney function.
2. Lymphangiography: A procedure to visualize the lymphatic system.
3. Surgical navigation: In some surgical procedures, fluorescein is used as a marker for better visualization of specific structures or areas.
"Fusarium" is a genus of fungi that are widely distributed in the environment, particularly in soil, water, and on plants. They are known to cause a variety of diseases in animals, including humans, as well as in plants. In humans, Fusarium species can cause localized and systemic infections, particularly in immunocompromised individuals. These infections often manifest as keratitis (eye infection), onychomycosis (nail infection), and invasive fusariosis, which can affect various organs such as the lungs, brain, and bloodstream. Fusarium species produce a variety of toxins that can contaminate crops and pose a threat to food safety and human health.
Meibomian glands are sebaceous glands located in the eyelids, specifically at the rim of the eyelid near the lashes. They produce an oily substance called meibum that forms the outermost layer of the tear film, helping to prevent evaporation and keep the eye surface lubricated. The Meibomian glands play a crucial role in maintaining the health and comfort of the eyes by providing stability to the tear film and protecting the eye from irritants and dryness.
Eye injuries refer to any damage or trauma caused to the eye or its surrounding structures. These injuries can vary in severity and may include:
1. Corneal abrasions: A scratch or scrape on the clear surface of the eye (cornea).
2. Chemical burns: Occurs when chemicals come into contact with the eye, causing damage to the cornea and other structures.
3. Eyelid lacerations: Cuts or tears to the eyelid.
4. Subconjunctival hemorrhage: Bleeding under the conjunctiva, the clear membrane that covers the white part of the eye.
5. Hyphema: Accumulation of blood in the anterior chamber of the eye, which is the space between the cornea and iris.
6. Orbital fractures: Breaks in the bones surrounding the eye.
7. Retinal detachment: Separation of the retina from its underlying tissue, which can lead to vision loss if not treated promptly.
8. Traumatic uveitis: Inflammation of the uvea, the middle layer of the eye, caused by trauma.
9. Optic nerve damage: Damage to the optic nerve, which transmits visual information from the eye to the brain.
Eye injuries can result from a variety of causes, including accidents, sports-related injuries, violence, and chemical exposure. It is important to seek medical attention promptly for any suspected eye injury to prevent further damage and potential vision loss.
In the field of medicine, "time factors" refer to the duration of symptoms or time elapsed since the onset of a medical condition, which can have significant implications for diagnosis and treatment. Understanding time factors is crucial in determining the progression of a disease, evaluating the effectiveness of treatments, and making critical decisions regarding patient care.
For example, in stroke management, "time is brain," meaning that rapid intervention within a specific time frame (usually within 4.5 hours) is essential to administering tissue plasminogen activator (tPA), a clot-busting drug that can minimize brain damage and improve patient outcomes. Similarly, in trauma care, the "golden hour" concept emphasizes the importance of providing definitive care within the first 60 minutes after injury to increase survival rates and reduce morbidity.
Time factors also play a role in monitoring the progression of chronic conditions like diabetes or heart disease, where regular follow-ups and assessments help determine appropriate treatment adjustments and prevent complications. In infectious diseases, time factors are crucial for initiating antibiotic therapy and identifying potential outbreaks to control their spread.
Overall, "time factors" encompass the significance of recognizing and acting promptly in various medical scenarios to optimize patient outcomes and provide effective care.
Pseudomonas infections are infections caused by the bacterium Pseudomonas aeruginosa or other species of the Pseudomonas genus. These bacteria are gram-negative, opportunistic pathogens that can cause various types of infections, including respiratory, urinary tract, gastrointestinal, dermatological, and bloodstream infections.
Pseudomonas aeruginosa is a common cause of healthcare-associated infections, particularly in patients with weakened immune systems, chronic lung diseases, or those who are hospitalized for extended periods. The bacteria can also infect wounds, burns, and medical devices such as catheters and ventilators.
Pseudomonas infections can be difficult to treat due to the bacteria's resistance to many antibiotics. Treatment typically involves the use of multiple antibiotics that are effective against Pseudomonas aeruginosa. In severe cases, intravenous antibiotics or even hospitalization may be necessary.
Prevention measures include good hand hygiene, contact precautions for patients with known Pseudomonas infections, and proper cleaning and maintenance of medical equipment.
Corneal endothelial cell loss refers to the decrease in the number of corneal endothelial cells, which is a layer of cells that line the inner surface of the cornea. These cells are essential for maintaining the clarity and health of the cornea, as they help to pump fluids out of the cornea and maintain its transparency.
Corneal endothelial cell loss can occur due to various reasons such as aging, eye trauma, surgery (such as cataract surgery), diseases (such as Fuchs' dystrophy), or inherited conditions. When the number of endothelial cells decreases below a certain threshold, it can lead to corneal swelling, cloudiness, and vision loss.
The rate of corneal endothelial cell loss varies from person to person, but on average, people lose about 0.6% of their endothelial cells per year. Factors such as age, certain medical conditions, and previous eye surgery can increase the rate of cell loss. In some cases, corneal transplantation may be necessary to replace damaged or lost endothelial cells and restore vision.
Diagnostic techniques in ophthalmology refer to the various methods and tests used by eye specialists (ophthalmologists) to examine, evaluate, and diagnose conditions related to the eyes and visual system. Here are some commonly used diagnostic techniques:
1. Visual Acuity Testing: This is a basic test to measure the sharpness of a person's vision. It typically involves reading letters or numbers from an eye chart at a specific distance.
2. Refraction Test: This test helps determine the correct lens prescription for glasses or contact lenses by measuring how light is bent as it passes through the cornea and lens.
3. Slit Lamp Examination: A slit lamp is a microscope that allows an ophthalmologist to examine the structures of the eye, including the cornea, iris, lens, and retina, in great detail.
4. Tonometry: This test measures the pressure inside the eye (intraocular pressure) to detect conditions like glaucoma. Common methods include applanation tonometry and non-contact tonometry.
5. Retinal Imaging: Several techniques are used to capture images of the retina, including fundus photography, fluorescein angiography, and optical coherence tomography (OCT). These tests help diagnose conditions like macular degeneration, diabetic retinopathy, and retinal detachments.
6. Color Vision Testing: This test evaluates a person's ability to distinguish between different colors, which can help detect color vision deficiencies or neurological disorders affecting the visual pathway.
7. Visual Field Testing: This test measures a person's peripheral (or side) vision and can help diagnose conditions like glaucoma, optic nerve damage, or brain injuries.
8. Pupillary Reactions Tests: These tests evaluate how the pupils respond to light and near objects, which can provide information about the condition of the eye's internal structures and the nervous system.
9. Ocular Motility Testing: This test assesses eye movements and alignment, helping diagnose conditions like strabismus (crossed eyes) or nystagmus (involuntary eye movement).
10. Corneal Topography: This non-invasive imaging technique maps the curvature of the cornea, which can help detect irregularities, assess the fit of contact lenses, and plan refractive surgery procedures.
Blinking is the rapid and repetitive closing and reopening of the eyelids. It is a normal physiological process that helps to keep the eyes moist, protected and comfortable by spreading tears over the surface of the eye and removing any foreign particles or irritants that may have accumulated on the eyelid or the conjunctiva (the mucous membrane that covers the front of the eye and lines the inside of the eyelids).
Blinking is controlled by the facial nerve (cranial nerve VII), which sends signals to the muscles that control the movement of the eyelids. On average, people blink about 15-20 times per minute, but this rate can vary depending on factors such as mood, level of attention, and visual tasks. For example, people tend to blink less frequently when they are concentrating on a visual task or looking at a screen, which can lead to dry eye symptoms.
Conjunctival diseases refer to a group of medical conditions that affect the conjunctiva, which is the thin, clear mucous membrane that covers the inner surface of the eyelids and the white part of the eye (known as the sclera). The conjunctiva helps to keep the eye moist and protected from irritants.
Conjunctival diseases can cause a range of symptoms, including redness, itching, burning, discharge, grittiness, and pain. Some common conjunctival diseases include:
1. Conjunctivitis (pink eye): This is an inflammation or infection of the conjunctiva that can be caused by viruses, bacteria, or allergies. Symptoms may include redness, itching, discharge, and watery eyes.
2. Pinguecula: This is a yellowish, raised bump that forms on the conjunctiva, usually near the corner of the eye. It is caused by an overgrowth of connective tissue and may be related to sun exposure or dry eye.
3. Pterygium: This is a fleshy growth that extends from the conjunctiva onto the cornea (the clear front part of the eye). It can cause redness, irritation, and vision problems if it grows large enough to cover the pupil.
4. Allergic conjunctivitis: This is an inflammation of the conjunctiva caused by an allergic reaction to substances such as pollen, dust mites, or pet dander. Symptoms may include redness, itching, watery eyes, and swelling.
5. Chemical conjunctivitis: This is an irritation or inflammation of the conjunctiva caused by exposure to chemicals such as chlorine, smoke, or fumes. Symptoms may include redness, burning, and tearing.
6. Giant papillary conjunctivitis (GPC): This is a type of allergic reaction that occurs in response to the presence of a foreign body in the eye, such as a contact lens. Symptoms may include itching, mucus discharge, and a gritty feeling in the eye.
Treatment for conjunctival diseases depends on the underlying cause. In some cases, over-the-counter medications or home remedies may be sufficient to relieve symptoms. However, more severe cases may require prescription medication or medical intervention. It is important to consult with a healthcare provider if you experience persistent or worsening symptoms of conjunctival disease.
Fungi, in the context of medical definitions, are a group of eukaryotic organisms that include microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The study of fungi is known as mycology.
Fungi can exist as unicellular organisms or as multicellular filamentous structures called hyphae. They are heterotrophs, which means they obtain their nutrients by decomposing organic matter or by living as parasites on other organisms. Some fungi can cause various diseases in humans, animals, and plants, known as mycoses. These infections range from superficial, localized skin infections to systemic, life-threatening invasive diseases.
Examples of fungal infections include athlete's foot (tinea pedis), ringworm (dermatophytosis), candidiasis (yeast infection), histoplasmosis, coccidioidomycosis, and aspergillosis. Fungal infections can be challenging to treat due to the limited number of antifungal drugs available and the potential for drug resistance.
Epithelium is the tissue that covers the outer surface of the body, lines the internal cavities and organs, and forms various glands. It is composed of one or more layers of tightly packed cells that have a uniform shape and size, and rest on a basement membrane. Epithelial tissues are avascular, meaning they do not contain blood vessels, and are supplied with nutrients by diffusion from the underlying connective tissue.
Epithelial cells perform a variety of functions, including protection, secretion, absorption, excretion, and sensation. They can be classified based on their shape and the number of cell layers they contain. The main types of epithelium are:
1. Squamous epithelium: composed of flat, scalelike cells that fit together like tiles on a roof. It forms the lining of blood vessels, air sacs in the lungs, and the outermost layer of the skin.
2. Cuboidal epithelium: composed of cube-shaped cells with equal height and width. It is found in glands, tubules, and ducts.
3. Columnar epithelium: composed of tall, rectangular cells that are taller than they are wide. It lines the respiratory, digestive, and reproductive tracts.
4. Pseudostratified epithelium: appears stratified or layered but is actually made up of a single layer of cells that vary in height. The nuclei of these cells appear at different levels, giving the tissue a stratified appearance. It lines the respiratory and reproductive tracts.
5. Transitional epithelium: composed of several layers of cells that can stretch and change shape to accommodate changes in volume. It is found in the urinary bladder and ureters.
Epithelial tissue provides a barrier between the internal and external environments, protecting the body from physical, chemical, and biological damage. It also plays a crucial role in maintaining homeostasis by regulating the exchange of substances between the body and its environment.
Epithelial cells are types of cells that cover the outer surfaces of the body, line the inner surfaces of organs and glands, and form the lining of blood vessels and body cavities. They provide a protective barrier against the external environment, regulate the movement of materials between the internal and external environments, and are involved in the sense of touch, temperature, and pain. Epithelial cells can be squamous (flat and thin), cuboidal (square-shaped and of equal height), or columnar (tall and narrow) in shape and are classified based on their location and function.
A "colony count" is a method used to estimate the number of viable microorganisms, such as bacteria or fungi, in a sample. In this technique, a known volume of the sample is spread onto the surface of a solid nutrient medium in a petri dish and then incubated under conditions that allow the microorganisms to grow and form visible colonies. Each colony that grows on the plate represents an individual cell (or small cluster of cells) from the original sample that was able to divide and grow under the given conditions. By counting the number of colonies that form, researchers can make a rough estimate of the concentration of microorganisms in the original sample.
The term "microbial" simply refers to microscopic organisms, such as bacteria, fungi, or viruses. Therefore, a "colony count, microbial" is a general term that encompasses the use of colony counting techniques to estimate the number of any type of microorganism in a sample.
Colony counts are used in various fields, including medical research, food safety testing, and environmental monitoring, to assess the levels of contamination or the effectiveness of disinfection procedures. However, it is important to note that colony counts may not always provide an accurate measure of the total number of microorganisms present in a sample, as some cells may be injured or unable to grow under the conditions used for counting. Additionally, some microorganisms may form clusters or chains that can appear as single colonies, leading to an overestimation of the true cell count.
Contact lens
Otto Wichterle
Herbert E. Kaufman
Fulmer Research Institute
Drahoslav Lím
Pinguecula
Hydroxyethyl)methacrylate
List of soft contact lens materials
Edward Wilson Merrill
Polymacon
List of MeSH codes (E07)
Polyhydroxyethylmethacrylate
Intraocular lens
Keratoconus
Jindřich Kopeček
Lacritin
Poloxamer 407
Poly(methyl methacrylate)
Cataract surgery
Hydrogel
Polydimethylsiloxane
Captive bubble method
Iridodialysis
Hydroxypropyl cellulose
Self-cleaning glass
Protein crystallization
Mucus
Artificial enzyme
Ultra-high-purity steam for oxidation and annealing
David J. Apple
Contact Lenses, Hydrophilic | Profiles RNS
Soft (Hydrophilic) Daily Wear Contact Lenses - Performance Criteria for Safety and Performance Based Pathway | FDA
Contact lens - Wikipedia
Scanning electron microscopy of the early host inflammatory response in experimental Pseudomonas keratitis and contact lens wear
Eye
Corneal Mucous Plaques: Background, Pathophysiology, Epidemiology
Contact Lens Materials: What You Need to Know
SENSIMED Triggerfish Electronic Contact Lens Provides Continuous Monitoring of Intraocular Pressure
Bausch & Lomb Boston Advance Contact Lens Cleaner Count of 1 By Bausch And Lomb | Shop Bausch & Lomb Boston Advance Contact...
PDAC - 2023 HCPCS Code Update - October Edition - Correct Coding
Coopervision Biofinity Contact Lenses | Lenstore
Prospective, non-randomised, long term clinical evaluation of a foldable hydrophilic single piece intraocular lens: results of...
May 2022 510(K) Clearances | FDA
Proclear® Monthly 6pk - Eye Contacts Australia
Supercapacitors: University research sees battery power revolution closer than ever | City & Business | Finance | Express.co.uk
Order Clearsight Contact Lenses Online | Reviews, Rebates, Cheap Replacements | Lens.com
Pharmaceutics | Free Full-Text | Therapeutic Ophthalmic Lenses: A Review
College of Health and Life Sciences - Research Outputs - Aston Research Explorer
CooperVision Showcases "Fit for the Future" with New Products and Education at SECO 2020 | CooperVision
Contact Lenses - Eye Disorders - MSD Manual Professional Edition
Гигантопапиларно запаљење вежњаче ока - Википедија
Comparison of fitting stability of the different soft toric contact lenses<...
Unique Gifts for Mom & Baby for the 2021 Holiday Season - Rookie Moms
CRSTG | Europe Edition | Lens-Based Solutions to the Aging Lens
Patents Assigned to Johnson & Johnson - Justia Patents Search
Buy Cheap monthly Contact Lenses online now | Contactlenses.co.uk
Eye & Lens Care
STEM Engineering: Biomaterials to Make Your Own Contact Lenses | Sargent Welch
Roberts, B.<...
Aston Publications Explorer
Wearers16
- As of 2010[update], the average age of contact lens wearers globally was 31 years old, and two-thirds of wearers were female. (wikipedia.org)
- Contact lens wearers can also wear sunglasses, goggles, or other eyewear of their choice without having to fit them with prescription lenses or worry about compatibility with glasses. (wikipedia.org)
- Cost-effective in the long run - Due to their extended lifespan, many wearers may find RGP lenses to be more economical over time when compared to regularly replaced soft lenses. (1800getlens.com)
- Ideal for special eye needs - RGP lenses are particularly beneficial for wearers with keratoconus and high levels of astigmatism than standard soft lenses. (1800getlens.com)
- This increased oxygen permeability means that wearers can safely use these silicone hydrogel lenses for extended periods. (1800getlens.com)
- The flexibility of soft lenses allows them to easily conform to the eye's shape, making them especially user-friendly for first-time wearers. (1800getlens.com)
- 90% of wearers are likely to stay in Biofinity® as their lenses of choice. (lenstore.co.uk)
- New materials can help enhance oxygen and water permeability, providing increased comfort and safety to contact lens wearers. (sigmaaldrich.com)
- In fact, they are the only contact lenses with an FDA clearance for the claim: [may provide improved comfort for contact lens wearers who experience mild discomfort or symptoms relating to dryness during lens wear. (eyecontacts.com.au)
- Dailies like ClearSight contacts are also convenient, especially for new and young lens wearers. (lens.com)
- Monthly disposable contact lenses are one of the most Eco-friendly options for contact lens wearers, because instead of throwing away 2 plastic blisters (currently it is hard to find a recycling centre that will take these) per day you only throw out 2 plastic blisters per month. (contactlenses.co.uk)
- In fact, many wearers cannot tell the difference between these and other contact lenses that they have worn. (brighteyestampa.com)
- Purpose: To investigate characteristics of the eyelid margins, meibomian glands and the tear film of contact lens wearers, and to determine whether these characteristics were related to symptoms of contact lens discomfort. (edu.au)
- Conclusions: Morphological irregularities of the meibomian glands and alterations to tear film secretions that affect tear evaporative dynamics were associated with symptoms of discomfort amongst the symptomatic lens wearers. (edu.au)
- Half of wearers experience dry eyes from contact lenses, and playing Contact Lens Roulette is no fun for anyone. (lenspure.com)
- Experts agree the multifocal contact lenses are especially useful for first-time wearers or those over the age of 40, who may have more sensitive eyes. (lenspure.com)
CooperVision7
- Biofinity® contact lenses are manufactured by CooperVision® , a world leader in contact lenses. (lenstore.co.uk)
- ClearSight contacts from CooperVision are daily disposable lenses. (lens.com)
- Clearsight contacts are made by CooperVision, the same maker as the ultra popular Biofinity line of contacts. (lens.com)
- To help eye care professionals successfully transition astigmatic patients into their presbyopic years, CooperVision will share more information at its exhibit (#927) about the forthcoming Biofinity ® toric multifocal contact lenses. (coopervision.com)
- Study lenses were PureVision ® Toric (B&L), Air Optix ® for Astigmatism (Alcon), Biofinity ® Toric (CooperVision), Acuvue ® Advance for Astigmatism (Vistakon), and Proclear ® Toric (CooperVision). (aston.ac.uk)
- At Bright Eyes we are proud to offer the CooperVision Brilliant Futures Myopia Management Program featuring MiSight 1 day contact lenses, the first and only FDA approved* contact lens to slow myopia progression of myopia in children. (brighteyestampa.com)
- That brand was CooperVision for its Proclear lenses. (lenspure.com)
Astigmatism9
- Versatility - Soft lenses come in a variety of designs to suit different vision needs, including spherical (for myopia or hyperopia), toric (for astigmatism), multifocal (for presbyopia), and even cosmetic (to change eye color). (1800getlens.com)
- May not be ideal for certain prescriptions - Soft lenses may not provide as crisp a vision as RGP lenses for high levels of astigmatism and other eye conditions. (1800getlens.com)
- A molded contact lens comprising a stiffer optic zone relative to the peripheral zone of the contact lens provides an optical element for correcting astigmatism without the need for or substantially minimizing the need for the correction of rotational misalignment. (justia.com)
- MiSight® 1 day (omafilcon A) soft (hydrophilic) contact lenses for daily wear are indicated for the correction of myopic ametropia and for slowing the progression of myopia in children with non-diseased eyes, who at the initiation of treatment are 8-12 years of age and have a refraction of -0.75 to 4.00 diopters (spherical equivalent) with ≤ 0.75 diopters of astigmatism. (brighteyestampa.com)
- The lens may be worn by persons who exhibit refractive astigmatism of .50 diopters or less where the astigmatism does not interfere with visual acuity. (desioeyes.com)
- My-contactlens.com provides you with variety of contact lenses , from big eyes contact lenses , clear contact lenses , natural contact lenses , contact lenses for astigmatism and if you are in a mood for some crazy event we do have halloween and cosplay contact lenses . (my-contactlens.com)
- A contact lens is a very thin, curved piece of lens that is placed in front of the cornea (front of the eye) to correct refractive errors: nearsightedness, farsightedness and astigmatism. (tibhealth.com)
- Can I wear contact lenses if I have astigmatism? (tibhealth.com)
- Patients with high astigmatism usually have better vision with semi-rigid contact lenses. (tibhealth.com)
Cornea14
- However, the idea was impracticable, since the device was to be placed in direct contact with the cornea and thus would have made blinking impossible. (wikipedia.org)
- These were much smaller than the original scleral lenses, as they sat only on the cornea rather than across all of the visible ocular surface, and could be worn up to 16 hours a day. (wikipedia.org)
- Because contact lens wear causes changes in tear film and corneal metabolism and can render the cornea susceptible to bacterial invasion, we examined the role of contact lens wear in Pseudomonas aeruginosa (P. aeruginosa) keratitis and its relation to the early defense mechanism, specifically whether the acute polymorphonuclear leukocyte (PMN) response is altered by contact lens wear. (nih.gov)
- Support optimal eye health - The permeability of RGP lenses means they allow more oxygen to reach the cornea than standard soft lenses. (1800getlens.com)
- Some soft contact lenses are made of silicone hydrogels, which allow even greater levels of oxygen to reach the cornea. (1800getlens.com)
- Lower oxygen permeability - Standard hydrogel soft lenses may not allow as much oxygen to pass through to the cornea as some other lens types. (1800getlens.com)
- Poor contact lens hygiene may lead to infection of the cornea or persistent inflammation. (msdmanuals.com)
- There is too little moisture to keep the lens floating above the cornea. (msdmanuals.com)
- A small foreign particle (eg, soot, dust) becomes trapped between the lens and the cornea. (msdmanuals.com)
- which is a potentially vision-threatening infection of the cornea, is suspected when a contact lens wearer has intense eye pain (both foreign body sensation and ache), decreased vision, redness, photophobia, and tearing. (msdmanuals.com)
- The higher elastic modulus optic zone vaults over the cornea thereby allowing a tear lens to form. (justia.com)
- Silicone Hydrogel contact lenses - were launched in the early 2000's and are loved by Optometrists as the addition of silicone allows more oxygen to reach the cornea creating a safer, healthier contact lens (1). (contactlenses.co.uk)
- The contacts are thinner by applying multiple curves on the front, and the edge curve calculated for the cornea and curvature curve is designed once more to provide a comfortable fit with smooth tear circulation. (fantasy-icon.com)
- These contact lenses only protect the cornea, which leaves the conjunctiva and adnexa exposed to UV light. (contactlensupdate.com)
Multifocal7
- Biofinity® monthly lenses are available as both toric and multifocal lenses. (lenstore.co.uk)
- The innovative lenses combine the proven optical design features of CooperVision's Biofinity ® toric-the most prescribed toric lens on the market 1 -and Biofinity ® multifocal. (coopervision.com)
- Rigid and soft bifocal and multifocal contact lenses can also be successful, but the fitting procedure is time-consuming because precise alignment is essential. (msdmanuals.com)
- Can I use multifocal contact lenses? (tibhealth.com)
- Nowadays there are multifocal contact lenses with a wide variety of prescriptions and parameters to fit most eyes. (tibhealth.com)
- One method proposed to slow myopic progression is the use of center distance multifocal contact lenses. (contactlensupdate.com)
- however, some practitioners are already fitting children into center distance multifocal contact lenses. (contactlensupdate.com)
Polymers5
- Soft, supple contact lenses made of plastic polymers which interact readily with water molecules. (uams.edu)
- Hydrogel contact lenses, introduced in the 1960s, are primarily made from hydrophilic polymers. (1800getlens.com)
- The development and manufacture of contact and intraocular lenses relies on innovative, high-quality polymers and reagents. (sigmaaldrich.com)
- Hydrogel contact lenses - currently the most popular type of daily lenses, made from gel-like, water containing polymers, enabling the contact lenses to be extremely thin and malleable. (contactlenses.co.uk)
- These are three-dimensional polymeric networks, synthesized by crosslinking of hydrophilic polymers. (bvsalud.org)
Keratitis1
- Management of an unusual case of keratitis mucosa with hydrophilic contact lenses and N-acetylcysteine. (medscape.com)
Wear40
- This guidance document provides the FDA's recommendations on performance criteria to support premarket submissions for soft (hydrophilic) daily wear contact lenses in the Safety and Performance Based Pathway. (fda.gov)
- Under this framework, submitters planning to submit a 510(k) using the Safety and Performance Based Pathway for soft (hydrophilic) daily wear contact lenses will have the option to use the performance criteria proposed in this final guidance to support substantial equivalence, rather than a direct comparison of the performance of the subject device to that of a predicate device. (fda.gov)
- The recommendations are intended to promote consistency and facilitate efficient review of soft (hydrophilic) daily wear contact lenses. (fda.gov)
- People choose to wear contact lenses for many reasons. (wikipedia.org)
- Others wear contact lenses for functional or optical reasons. (wikipedia.org)
- Needs consistent wear - Extended breaks can make re-adaptation to RGP lenses challenging. (1800getlens.com)
- To maintain comfort, it's advised to wear RGP lenses consistently. (1800getlens.com)
- Biofinity® lenses are designed for daily wear for 30 days, which means they should be cleaned and stored overnight. (lenstore.co.uk)
- How long can you wear Biofinity® contacts? (lenstore.co.uk)
- However, before doing so, it's best to confirm with your optician how long you should keep your extended wear contact lenses in for. (lenstore.co.uk)
- Simply throw away your contacts at the end of the day and wear a brand new pair of contacts in the morning. (lens.com)
- Comfortable - Customers find that ClearSight contacts are non-drying, even after several hours of wear. (lens.com)
- Only Opti-Free PureMoist Rewetting Drops contains patented RLM-100, which helps prevent protein deposit buildup on soft (hydrophilic) lenses while you wear them, when used as directed. (shoprite.com)
- Giant papillary conjunctivitis induced by hard or soft contact lens wear: quantitative histology. (wikipedia.org)
- You can wear monthly lenses up to 30 times, replacing lenses on the same day every month helps you remember. (contactlenses.co.uk)
- All monthly contact lenses are designed to be worn for up to 30 days and removed, cleaned and stored overnight, except Air Optix night and day which have been approved for continual wear upto 30 days and nights. (contactlenses.co.uk)
- The brown color lenses are lightweight and soft to wear, fresh and comfortable while you are wearing them. (shopoptica.com)
- With your decision to wear soft (hydrophilic) contact lens, you have joined a growing number of people who are discovering new pleasures from this important advance in vision correction. (desioeyes.com)
- Your frequent/planned replacement DESIO ( polymacon ) Spherical and Toric Daily Wear Soft (hydrophilic) Contact Lens is made of a stable, inert, highly purified, hydrophilic (water absorbing) polymer with properties different from conventional rigid lens. (desioeyes.com)
- The life of your frequent/planned replacement DESIO ( polymacon ) Spherical and Toric Daily Wear Soft (hydrophilic) Contact Lenses will depend to a large extent on how you handle and care for them. (desioeyes.com)
- It contains the information you need to know to wear, handle, and care for your frequent/planned replacement DESIO ( polymacon ) Spherical and Toric Daily Wear Soft (hydrophilic) Contact Lenses . (desioeyes.com)
- The DESIO ( polymacon ) Spherical Soft Contact Lenses for daily wear are indicated for the correction of visual acuity in aphakic and not aphakic persons with non-diseased eyes with myopia or hyperopia. (desioeyes.com)
- Eyecare practitioners may prescribe any of the above lenses for frequent/planned replacement wear, with cleaning disinfection and scheduled replacement. (desioeyes.com)
- When prescribed for frequent/planned replacement wear, the lens should be removed from your eyes for routine cleaning and disinfecting daily as prescribed by your eyecare practitioner. (desioeyes.com)
- Extended wear contact lenses (EWCL) have been successfully used for the correction of aphakia. (eyehospital.nl)
- One patient discontinued lens wear because of discomfort without obvious clinical abnormalities. (eyehospital.nl)
- van Nes, H. / Silico-acrylate contact lenses for extended wear . (eyehospital.nl)
- Methods: A 66-year-old woman with an ocular history of bilateral soft contact lens wear presented with a large, 6×9-mm, culture-positive Pseudomonas aeruginosa-induced corneal ulcer. (houstonmethodist.org)
- Biofinity's lenses are made for monthly wear, making them a tad easier on the wallet than daily lenses. (lenspure.com)
- These one-day lenses offer a whopping 60% water content and, according to the company, offer 96% hydration for up to 12 hours of wear. (lenspure.com)
- If the patient practices any sport, it will always be more comfortable, especially if it is a contact sport where he/she cannot wear glasses. (tibhealth.com)
- Soft contact lenses range from daily replacement (wear and tear) to annual replacement. (tibhealth.com)
- Can I wear contact lenses if I have dry eye? (tibhealth.com)
- From what age can my child wear contact lenses? (tibhealth.com)
- During the first few years of lens wear, it is recommended to increase the frequency of check-ups. (tibhealth.com)
- Can I wear contact lenses in the office? (tibhealth.com)
- This could be one reason that one study showed that patients who discontinue lens wear have a lower prescription on average than those that do not discontinue lens wear. (contactlensupdate.com)
- Despite the ability of these lenses to block UV light, we should continue to encourage patients who wear these lenses to also use sunglasses and other forms of UV protection. (contactlensupdate.com)
- If patients only wear lenses a few times a week or a few times a month, a monthly or biweekly lens is likely to sit in solution that is days or weeks old. (contactlensupdate.com)
- Examples include corneal or epithelial disease (eg, dry eye), superficial corneal injury or ocular injuries (eg, those due to foreign bodies), and contact lens wear (eg, daily disposable soft lenses, extended-wear soft lenses, gas-permeable lenses, hard polymethylmethacrylate lenses). (medscape.com)
Rigid10
- Rigid gas-permeable (RGP) lenses are made from a combination of silicone and fluoropolymers. (1800getlens.com)
- Developed in the 1970s, hydrogels revolutionized the contact lens industry by providing a more flexible and comfortable alternative to rigid lenses. (1800getlens.com)
- Either soft or rigid lenses are used to correct myopia and hyperopia. (msdmanuals.com)
- Neither rigid nor soft contact lenses offer the eyes the protection against blunt or sharp injury that eyeglasses do. (msdmanuals.com)
- Clear Care Plus with HydraGlyde Cleaning & Disinfectant Solution Twin Pack, 12 fl oz, 2 countnClear Care® Plus provides simultaneous cleaning, daily protein removal and disinfection of all types of contact lenses, including soft (hydrophilic), silicone hydrogel, and rigid gas permeable lenses.nnYou Can See It Working!nOur unique lens case features a platinum disc which activates a gentle, bubbling action and neutralizes the hydrogen peroxide into a mild saline solution. (fairwaymarket.com)
- Depending on the material they are made of, there are different types of contact lenses: semi-rigid, soft and hybrid. (tibhealth.com)
- Semi-rigid contact lenses are made of rigid plastics. (tibhealth.com)
- In hybrid contact lenses, used in very specific cases, the center is like a semi-rigid contact lens and the periphery is like a soft lens. (tibhealth.com)
- They are used in patients who need the benefits of the semi-rigid lens and cannot tolerate them because of the discomfort involved. (tibhealth.com)
- In contrast, semi-rigid contact lenses are usually replaced annually. (tibhealth.com)
Surface12
- Contact lenses, or simply contacts, are thin lenses placed directly on the surface of the eyes. (wikipedia.org)
- Monomer selection impacts a number of lens attributes such as modulus, permeability, surface smoothness, UV radiation absorption and resistance to tearing and surface defects. (sigmaaldrich.com)
- Thanks to PC Technology, Proclear lenses will hold water for longer periods of time and have less surface evaporation. (eyecontacts.com.au)
- PC Technology also attracts and binds water to the lens surface - and a shield is created that keeps the lenses clean and functioning properly. (eyecontacts.com.au)
- The tear lens follows or assumes the shape of the back surface of the contact lens. (justia.com)
- and a polymerization initiator, the contact lens having an oxygen permeability of at least about 60 barrers, and wherein the molar ratio in the lens of the polymeric non-reactive internal wetting agent to silicone, without a surface treatment, is greater in the lens's surface than in its bulk. (justia.com)
- The amount of peptide present on the lens surface was quantified using amino acid analysis. (aston.ac.uk)
- After coating, the heat stability (121°C), lens surface hydrophobicity (by captive bubble), and in vitro cytotoxicity to mouse L929 cells of the lenses were investigated. (aston.ac.uk)
- The most effective concentration was determined to be 152 ± 44 lg lens-1 melimine on the lens surface. (aston.ac.uk)
- No need to worry about pigmentation, decolorization, or discoloration because the special coating is applied to the contacts surface with a minimal amount of dye used to express the natural color. (fantasy-icon.com)
- The new technology includes an "ultrasoft, hydrophilic surface gel. (lenspure.com)
- Depending on the contact lens and the ocular surface, it is necessary to use a specific type of solution to be decided by the specialist. (tibhealth.com)
Deposit buildup2
- High maintenance - With the exception of daily disposables, soft lenses require a consistent cleaning routine to prevent deposit buildup and potential eye infections. (1800getlens.com)
- Because of their frequent replacement schedule, dailies like ClearSight contacts are less prone to deposit buildup that can otherwise cause irritation. (lens.com)
Monomers1
- Hydrophilic monomers are included to always keep moisture and comfortability even after long hours of wearing. (fantasy-icon.com)
Disposable contact lenses7
- Proclear monthly disposable contact lenses will feel as fresh and comfortable at the end of the day as when you first put them in. (eyecontacts.com.au)
- Monthly disposable contact lenses are designed to be worn on a daily basis, up to 30 days. (contactlenses.co.uk)
- There are however some drawback to monthly disposable contact lenses, the main one being the possible accumulation of debris such as proteins, lipids and pollen's, this can lead to increased eye irritation. (contactlenses.co.uk)
- If you don't have the time for a daily cleaning routine and are not committed to cleaning and storing lenses every evening then monthly contact lenses may not be the best choice for you,daily disposable contact lenses may be a better option. (contactlenses.co.uk)
- The increased prescribing of daily disposable contact lenses has been observed over the last few years. (contactlensupdate.com)
- Here, we aim to review some unique features and occasions to use daily disposable contact lenses. (contactlensupdate.com)
- 7,8 Daily disposable contact lenses are an obvious modality of choice for this treatment because it is best utilized in children, who benefit from the safety profile of daily disposable lenses. (contactlensupdate.com)
Monomer2
- and at least one hydrophilic monomer. (justia.com)
- 4- Transitions Light Intelligent Technology which is Naphthopyran monomer or the photochromic additive which are mixed into the soft hydrogel material of the lens. (webeyeclinic.com)
Proclear5
- Think of Proclear as the older brother of Biofinity® lenses, having been around 10 years longer. (lenstore.co.uk)
- Proclear Monthly Contact Lenses have superior resistance to lens dehydration and remain soft all day long. (eyecontacts.com.au)
- Its all down to PC Technology, which is within every lens in the Proclear family. (eyecontacts.com.au)
- It all means that Proclear lenses remain hydrated, which helps them feel moist and comfortable all day long. (eyecontacts.com.au)
- While the other Proclear products were also given the go-ahead to cite improved comfort by the FDA, the one-day lenses are especially beneficial for dry eyes. (lenspure.com)
Ocular2
- Contact lenses are ocular prosthetic devices used by over 150 million people worldwide, and they can be worn to correct vision or for cosmetic or therapeutic reasons. (wikipedia.org)
- Eyelid signs and tear film characteristics were evaluated during a single visit and subjects completed the contact lens and dry eye questionnaire (CLDEQ-8) to evaluate ocular discomfort. (edu.au)
Hydrogel and silicone hydrogel2
- Monthly contact lenses can be subdivided into two main categories hydrogel and silicone hydrogel. (contactlenses.co.uk)
- Within soft contact lenses there are two main groups: hydrogel and silicone hydrogel. (tibhealth.com)
Discomfort2
- Initial discomfort - RGP lenses can take some time for users to get used to. (1800getlens.com)
- It also helps remove particulate material that may cause minor irritation, discomfort, dryness, blurring and itchiness while wearing your lenses. (shoprite.com)
Modality1
- 1 The contact lens industry has responded to the increased demand by continuously expanding parameters and introducing new products to this contact lens modality. (contactlensupdate.com)
Wearer2
- For the typical wearer, MiSight 1 Day contact lenses handle, feel, and provide the same vision as regular contact lenses. (brighteyestampa.com)
- If you're a contact lens wearer, the effects are practically doubled. (lenspure.com)
Provide better peripheral vision1
- When compared with spectacles, contact lenses typically provide better peripheral vision, and do not collect moisture (from rain, snow, condensation, etc.) or perspiration. (wikipedia.org)
Hydrogels2
- Soft contact lenses are primarily composed of gel-like, water-containing plastics known as hydrogels. (1800getlens.com)
- The biological macromolecules based hydrogels containing therapeutic substances are used in a wide range of biomedical applications including wound healing, tissue engineering, cosmetics and contact lenses. (bvsalud.org)
Anterior eye3
- Contact lens & anterior eye : the journal of the British Contact Lens Association. (aston.ac.uk)
- Contact Lens and Anterior Eye , 37 (5), 346-350. (aston.ac.uk)
- Contact Lens and Anterior Eye , 41 (2), 144-153. (edu.au)
Complications3
- This can help reduce the risk of contact lens-related complications, such as corneal oxygen deficiency. (1800getlens.com)
- The risk of contact lens-related complications is also reduced with silicone hydrogel lenses. (1800getlens.com)
- Daily disposables provide the advantage of fewer contact lens complications compared to other lenses and better comfort. (contactlensupdate.com)
MiSight11
- SECO attendees will also have the opportunity to learn firsthand about CooperVision's Brilliant Futures ™ Myopia Management Program, featuring MiSight ® 1 day contact lenses. (coopervision.com)
- The groundbreaking MiSight ® 1 day contact lenses recently became the first and only product approved by the U.S. Food and Drug Administration for slowing the progression of myopia in children (8-12 years of age at the initiation of treatment) 2 . (coopervision.com)
- Check out MiSight® 1 day contact lenses, which are the first and only soft contact lenses FDA- approved* to slow the progression of myopia, otherwise known as nearsightedness, in children, aged 8-12 at the initiation of treatment. (rookiemoms.com)
- We are proud to be among the first offices to offer MiSight 1 Day, the first FDA approved contact lens for reducing progression of myopia. (brighteyestampa.com)
- Are MiSight 1 Day contact lenses like regular contact lenses? (brighteyestampa.com)
- In many ways, MiSight 1 Day contact lenses are the same as other contact lenses. (brighteyestampa.com)
- How do MiSight 1 Day contact lenses work? (brighteyestampa.com)
- The special thing about MiSight 1 Day contact lenses its optics. (brighteyestampa.com)
- Our clinical experience shows that that MiSight 1 Day Lenses do reduce progression of myopia. (brighteyestampa.com)
- Because we are believers in Myopia Control and MiSight 1 Day contact lenses, we recommend them not only to our patients but have also provided them to children of Bright Eyes team members. (brighteyestampa.com)
- domized clinical trial of MiSight® lenses for myopia control. (brighteyestampa.com)
Optometrist5
- In 1936, optometrist William Feinbloom introduced a hybrid lens composed of glass and plastic, and in 1937 it was reported that some 3,000 Americans were already wearing contact lenses. (wikipedia.org)
- The following year, German optometrist Heinrich Wöhlk produced his own version of plastic lenses based on experiments performed during the 1930s. (wikipedia.org)
- Please always check with your optometrist first before purchasing new contact lenses that haven't been prescribed. (lenstore.co.uk)
- In overwear syndrome or any other condition in which pain does not quickly resolve when lenses are removed, an ophthalmologist or optometrist should be consulted before lenses are worn again. (msdmanuals.com)
- Buying contact lenses online from Contactlenses.co.uk is both easy and convenient, no need for trips to your Optometrist to collect your lenses, they are shipped directly to your door in recyclable packaging. (contactlenses.co.uk)
1960s1
- PMMA corneal lenses became the first contact lenses to have mass appeal through the 1960s, as lens designs became more sophisticated with improving manufacturing technology. (wikipedia.org)
Oxygen8
- This unique material composition makes the lenses hard, yet they still allow oxygen to permeate. (1800getlens.com)
- The water content in these lenses can vary, which influences their flexibility and oxygen permeability. (1800getlens.com)
- The high water content of these lenses provides the eyes with adequate oxygen through direct oxygen diffusion from the atmosphere. (1800getlens.com)
- Thanks to the unique Aquaform technology, the lenses allow plenty of oxygen to reach your eyes for optimal eye health. (lenstore.co.uk)
- Aquaform® technology combines naturally hydrophilic technologies with high oxygen transmissibility for added comfort and breathability. (lenstore.co.uk)
- Thanks to technological advancements, Biofinity® lenses allow more oxygen to reach the eyes and the Aquaform technology ensures eyes are kept more hydrated, too. (lenstore.co.uk)
- Air Optix Aqua contacts boast five times more oxygen flow than regular soft lenses. (lenspure.com)
- The latter is the lens that transmits more oxygen to the eye and, therefore, the most recommended in most cases. (tibhealth.com)
Refractive3
- He used wax to affix water-filled lenses to his eyes, neutralizing their refractive power, which he corrected with another pair of lenses. (wikipedia.org)
- Phakic IOL surgery also avoids the risks of postoperative corneal ectasia 5 and of retinal detachment associated with refractive lens exchange. (crstodayeurope.com)
- The combination of the tear lens and the optical zone provide an optical element for correction of refractive error. (justia.com)
Types of contact lenses1
- What types of contact lenses are there and how often should they be replaced? (tibhealth.com)
Material8
- Biofinity® lenses are made of Comfilcon A, a silicone hydrogel material with an impressive water content. (lenstore.co.uk)
- What kind of material does the Clearsight contact lens brand use? (lens.com)
- Clearsight contacts are made from hydrogel (ocufilcon B). They are made from a "water-loving" (hydrophilic) material that has the ability to absorb water, making the lens soft and flexible. (lens.com)
- For example, when developing the perfect material for use in contacts, an engineer will have to test many different materials before finding the right one. (sargentwelch.com)
- Students will engineer using 2 different materials, the correct material and concentration that has similar properties as a contact lens with discovering the correct optical properties, tensile strength and hydrophobicity. (sargentwelch.com)
- 2- Silicone hydrogel material (senofilcon A) with Hydraclear plus Technology which act as an embedded wetting agent in the lens to keep your eye moist all the day. (webeyeclinic.com)
- The material used to create these lenses is a high-performance silicone hydrogel which contains the company's Aquaform(R) technology. (lenspure.com)
- Touted as the "world's first and only water gradient contact lenses," its innovations allow users to enjoy six times more breathable material. (lenspure.com)
Biofinity Toric1
- Conclusion: Although there was appropriate fitting, based upon lens orientation and reorientation speed, with each of the study lenses it would appear that the optimized ballast technique used in the design of the Biofinity Toric helps reduce lens rotation and improve rotational recovery compared to others. (aston.ac.uk)
Worn6
- citation needed] Large and unwieldy, Fick's lens could be worn only for a couple of hours at a time. (wikipedia.org)
- Biofinity® are monthly lenses that can be worn for up to 30 days when removed, cleaned and stored properly overnight. (lenstore.co.uk)
- The lenses are worn for a long time (overwear syndrome). (msdmanuals.com)
- Spontaneous healing may occur in a day or so if lenses are not worn. (msdmanuals.com)
- The risk increases about 15 times if contact lenses are worn overnight. (msdmanuals.com)
- Because they are designed to be worn for one day and then disposed of, they are healthy and require minimal care compared to resendable contact lenses. (brighteyestampa.com)
Correction3
- In the world of vision correction, contact lenses have become an essential tool for many people. (1800getlens.com)
- I believed then, as I do now, that the aging lens presents an array of opportunities for surgical vision correction and that it is our duty to counsel patients and suggest the procedure for which they are best suited. (crstodayeurope.com)
- There are 2 myopic control zones and 2 correction zones in the lens. (brighteyestampa.com)
Daily disposables4
- These practitioners have the option of several lenses with a center distance design in other modalities, and these center distance designs have begun being manufactured as daily disposables. (contactlensupdate.com)
- Some patients may prefer monthly or biweekly lenses most of the time, but they have not considered the benefits of using daily disposables in other parts of their life. (contactlensupdate.com)
- For example, patients may benefit from daily disposables when traveling because bulky lens solutions do not have to be packed. (contactlensupdate.com)
- While each situation is different for these service men and women, daily disposables may offer some flexibility that will help them focus on their duties and less on where to place their contact lens solution and case. (contactlensupdate.com)
Irritate your eyes2
- This cleaner will irritate your eyes unless removed from lenses by thorough rinsing. (herbspro.com)
- Again, the daily use (compared to monthly lenses) also means fewer contagions that can irritate your eyes. (lenspure.com)
Water7
- Leonardo da Vinci is frequently credited with introducing the idea of contact lenses in his 1508 Codex of the eye, Manual D, wherein he described a method of directly altering corneal power by either submerging the head in a bowl of water or wearing a water-filled glass hemisphere over the eye. (wikipedia.org)
- If instilled into the eyes, immediately remove lenses and flush eyes with fresh tap water until cleaner is thoroughly removed from the eyes. (herbspro.com)
- ClearSight contacts also have a high water content to keep your eyes moist all day. (lens.com)
- The main job of a biomedical engineer developing contact lenses today is to make a hydrogel and find the perfect "ratio" of polymer to water so that the composition of the hydrogel is hydrophilic enough to maintain a wet environment in the eye but not too hydrophilic so that the contact begins to swell and change size and shape. (sargentwelch.com)
- An aqueous cleaning dispersion, especially suitable as a contact lens cleaning solution, which includes a homogeneous mixture of water and a liquid-adsorbable powder homopolymer of tetraethylene glycol dimethacrylate. (justia.com)
- The moisture in a lens can dry out your eyes by attracting the water in your eyeballs, making your eyes even worse off than before. (lenspure.com)
- Soft contact lenses are made of hydrophilic (water-absorbing) plastic. (tibhealth.com)
Abstract1
- abstract = "Purpose: To compare lens orientation and rotational recovery of five currently available soft toric lenses. (aston.ac.uk)
Corneal epithelium1
- Contact lens-related abrasions are defects in the corneal epithelium that are left behind after the removal of an overworn, improperly fitting, or improperly cleaned contact lens. (medscape.com)
Myopia control2
- 3. Chamberlain P, Logan N, Jones D, Gonzalez-Meijome J, Saw S-M, Young G. Clinical evaluation of a dual-focus myopia control 1 day soft contact lens: 6-year results (2020 American Academy of Optometry Annual Meeting). (brighteyestampa.com)
- The use of these lenses for myopia control is not approved or proven effective, but it may be an option for practitioners who would like to treat a patient before the introduction of lenses specifically designed for myopia control. (contactlensupdate.com)
Soft lenses8
- Their rigidity means they maintain their shape even when you blink, preventing the distortion that can sometimes happen with soft lenses. (1800getlens.com)
- Durability - With proper care, RGP lenses can last considerably longer than soft lenses, often up to a year or more. (1800getlens.com)
- They can initially feel more uncomfortable or foreign than soft lenses. (1800getlens.com)
- Immediate comfort - Soft lenses are more comfortable right from the start than RGP lenses. (1800getlens.com)
- Available in various modalities - Soft lenses are available in multiple replacement schedules, including daily, bi-weekly, and monthly options, catering to different lifestyles and preferences. (1800getlens.com)
- Can dry out - Soft lenses may become less comfortable in dry environments or during prolonged screen time. (1800getlens.com)
- Fragile - Due to their pliability, soft lenses can be more prone to tearing or damage, especially during insertion or removal. (1800getlens.com)
- Soft lenses are also better suited for those with dry eyes. (lenspure.com)
Made6
- Made with silicone hydrogel, Biofinity® lenses provide long-lasting comfort and hydration throughout the entire month. (lenstore.co.uk)
- These lenses are made of breathable silicone hydrogel, which keeps the eyes fresh and healthy. (lenstore.co.uk)
- There may be a delay for some toric and multi-focal prescriptions and for custom made contact lenses. (eyecontacts.com.au)
- Contact lenses are not all created equal, they are made using different materials and designs which result in a different fit on the eyeball, so it is VERY important to order the exact lenses you have a prescription for. (eyecontacts.com.au)
- Fantasy-icon treats only branded products such as I-Contacts, INNOVISION, BS, MI, NEO COSMO etc.) and All of our products are made through the strict quality control and inspection. (fantasy-icon.com)
- There are lenses out there made specifically for people with eyes just like yours. (lenspure.com)
Moisture2
- Month-long comfort - Aquaform® technology locks in moisture, keeping the lens clean and comfy throughout the entire month. (lenstore.co.uk)
- Contrary to popular belief, more moisture content in a contact lens does not mean the lens will help your dry eyes. (lenspure.com)
Dryness1
- This is because they avoid letting any debris or bacteria build up on the lens, which further affects dryness. (lenspure.com)
PureVision 2 HD1
- PureVision 2 HD are thin and comfortable lenses with unique High-Definition Optics that help to ensure sharpness of vision by reducing halos and glare. (lenstore.co.uk)
Monthly Contact Lenses3
- Monthly contact lenses are also one of the most cost effective contact lens options, even when solutions are taken into account, monthly lenses can work out cheaper than daily contact lenses. (contactlenses.co.uk)
- Monthly contact lenses create less waste - only 2 plastic blisters per month instead of 60. (contactlenses.co.uk)
- Cost effective - Monthly contact lenses can work out as the cheapest option even when solution prices are taken into account. (contactlenses.co.uk)
Ophthalmologist2
- Although Louis J. Girard invented a scleral contact lens in 1887, it was German ophthalmologist Adolf Gaston Eugen Fick who in 1888 fabricated the first successful afocal scleral contact lens. (wikipedia.org)
- In 1939, Hungarian ophthalmologist Dr.István Györffy produced the first fully plastic contact lens. (wikipedia.org)