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  • retina
  • In farsightedness ( hyperopia ) the image is focused behind the retina because the refractive power of the lens is too weak or the eyeball axis is too short. (thefreedictionary.com)
  • Nearsightedness ( myopia ) occurs when the refractive power of the lens is too strong or the eyeball is too long, so that the image is focused in front of the retina. (thefreedictionary.com)
  • The lens of the eye is a biconvex, relatively acellular, optically transparent intraocular structure that with the cornea serves to transmit light to the retina with minimal light scattering (Fig. 1a). (utah.edu)
  • We now know that this is the function of the retina, with the lens serving as a conduit of light transmission and focus to the retina. (utah.edu)
  • The lens can change shape with the aid of the ciliary muscles, thereby changing the focal distance to the retina and bringing the image into sharp focus on the retina. (utah.edu)
  • A human eyeball cut in half to show the lens and the passage of light through it from the object ahead to the focus on the retina. (utah.edu)
  • Years after returning to Earth, many of these astronauts developed cataracts--a clouding of the lens, which focuses light onto the retina. (nasa.gov)
  • The lens, shaped like an M&M, sits in the opening of the eye and focuses incoming light onto the retina. (nasa.gov)
  • As people age, they experience neurodegeneration in the retina and in the suprachiasmatic nucleus (SCN). (wikipedia.org)
  • The lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to be focused on the retina. (wikipedia.org)
  • The lens, by changing shape, functions to change the focal distance of the eye so that it can focus on objects at various distances, thus allowing a sharp real image of the object of interest to be formed on the retina. (wikipedia.org)
  • Birds and mammals (including humans) normally adjust focus by changing the shape of their lens, but fish normally adjust focus by moving the lens closer to or further from the retina. (wikipedia.org)
  • Once light passes through the lens it is transmitted through a transparent liquid medium until it reaches the retina, containing the photoreceptors. (wikipedia.org)
  • Together the cornea and lens refract light into a small image and shine it on the retina. (wikipedia.org)
  • The cornea and lens act together as a compound lens to project an inverted image onto the retina. (wikipedia.org)
  • Fish and amphibians vary the power by changing the distance between a rigid lens and the retina with muscles. (wikipedia.org)
  • epithelial
  • This study was directed to assess the DNA damage and DNA repair response to X-ray inflicted lens oxidative damage and to investigate the subsequent changes in lens epithelial cell (LEC) behavior in vivo that led to long delayed but then rapidly developing cataracts. (nih.gov)
  • The inner side of the anterior capsule of the lens contain epithelial cells which migrate peripherally and posteriorly to lay down concentric lamellae of nuclear tissue. (google.com)
  • The process begins with "epithelial cells," a type of stem cell that coats the front of the lens. (nasa.gov)
  • When needed, epithelial cells flatten out and shed their nucleuses and other internal structures to become transparent fiber cells. (nasa.gov)
  • Blakely's group has shown that a radiation dose can upset the metamorphosis of epithelial cells, interfering with the formation of fresh fiber cells that make up the body of the lens. (nasa.gov)
  • As ions, nutrients, and liquid enter the lens from the aqueous humor, Na+/K+-ATPase pumps in the lens epithelial cells pump ions out of the lens to maintain appropriate lens osmotic concentration and volume, with equatorially positioned lens epithelium cells contributing most to this current. (wikipedia.org)
  • cataract surgery
  • Indeed, this is supported by clinical studies that reveal several critical aspects of cataract surgery are enhanced, including the ability to create the perfect capsulorrhexis , the formation of corneal and limbal relaxing incisions (of specific depth and diameter) and lens fragmentation (Table 6). (thefreedictionary.com)
  • During cataract surgery, a patient's cloudy natural cataract lens is removed and replaced with a synthetic lens to restore the lens's transparency. (wikipedia.org)
  • Manual small incision cataract surgery (MSICS): This technique is an evolution of ECCE (see below) where the entire lens is expressed out of the eye through a self-sealing scleral tunnel wound. (wikipedia.org)
  • arcuate
  • The arcuate nucleus produces inhibiting and releasing factors (adrenocorticotrophic hormone, beta-lipotrophic hormone, and beta-endorphin) for pituitary hormones. (thefreedictionary.com)
  • arcuate nuclei of medulla oblongata, nu´clei arcua´ti medul´lae oblonga´tae small irregular areas of gray substance on the ventromedial aspect of the pyramid of the medulla oblongata. (thefreedictionary.com)
  • amygdaloid
  • basal nuclei ( nu´clei basa´les ) specific interconnected subcortical masses of gray matter embedded in each cerebral hemisphere and in the upper brainstem , comprising the corpus striatum (caudate and lentiform nuclei), amygdaloid body , claustrum , and external, extreme, and internal capsules . (thefreedictionary.com)
  • electrons
  • Electrons are charged particles and therefore interact with the total charge distribution of both the atomic nuclei and the electrons of the sample. (wikipedia.org)
  • Antigravity - Antimatter - Antineutron - Antiparticle - Antiproton - Arc length - Archimedes' principle - Area moment of inertia - Astronomical unit - Astrophysics - The branch of astronomy that deals with the physics of the universe, especially with "the nature of the heavenly bodies, rather than their positions or motions in space Attenuation coefficient - Atom - A basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. (wikipedia.org)
  • protons
  • Alpha particle - Consist of two protons and two neutrons bound together into a particle identical to a helium nucleus, which is classically produced in the process of alpha decay, but may be produced also in other ways and given the same name. (wikipedia.org)
  • Proteins
  • As these cells migrate abnormally and leave acellular lens surface sites, eventually a crisis point may arrive for lens entry of environmental O(2) with resultant ROS formation that overwhelms protection by resident antioxidant enzymes and results in the coagulation of lens proteins. (nih.gov)
  • During the final stages," she says, "all of the cell's organelles are disposed of by the cell in a carefully orchestrated process that leaves the cell alive, but basically a bag of crystalline proteins. (nasa.gov)
  • Fernald also did research on eye evolution, showing that photoreceptor proteins have an ancient origin predating vision while lens proteins have arisen many times from different sources in different animal lineages. (wikipedia.org)
  • nuclear
  • In spite of the initial recovery of DNA strand breaks, a dysfunctional lens status increased over time as confirmed by confocal viewing of living lenses using fluorescent dyes for nuclear fragments, free DNA presence, and localized ROS presence as well as noting aberrant LEC migration within the lens. (nih.gov)
  • Nuclear sclerosis is an age-related change in the density of the crystalline lens nucleus that occurs in all older animals. (wikipedia.org)
  • Although nuclear sclerosis may describe a type of early cataract in human medicine, in veterinary medicine the term is also known as lenticular sclerosis and describes a bluish-grey haziness at the nucleus that usually does not affect vision, except for unusually dense cases. (wikipedia.org)
  • Nuclear sclerosis appears as a bilateral bluish-grey haziness at the nucleus, or center of the lens, caused by an increase in the refractive index of that part of the lens due to its increased density. (wikipedia.org)
  • This is possibly the case if you are developing a Nuclear Cataract-that is, one that is forming in the nucleus or center of the Crystalline Lens of your eye. (aboutcataractsurgery.com)
  • As a Nuclear Cataract develops, it causes a change in the refractive power of the Crystalline lens and thus the optical prescription of your eye. (aboutcataractsurgery.com)
  • cochlear
  • He was supported by the Ford Foundation and studied the neurobiology of the cat cochlear nucleus using single cell recording and modeling the data. (wikipedia.org)
  • center of the lens
  • At the center of the lens are transparent cells called 'fiber cells. (nasa.gov)
  • Ciliary muscle contraction initiates a pressure gradient between the vitreous and aqueous compartments that support the anterior lens shape in the mechanically reproducible state of a steep radius of curvature in the center of the lens with slight flattening of the peripheral anterior lens, i.e. the shape, in cross section, of a catenary. (wikipedia.org)
  • equator
  • This confocal view shows the loss of surface LEC and their descent into the lens interior at a site well anterior to the lens equator. (nih.gov)
  • The lens is suspended in place by the suspensory ligament of the lens, a ring of fibrous tissue that attaches to the lens at its equator and connects it to the ciliary body. (wikipedia.org)
  • cortical
  • Fragmentation into smaller pieces makes emulsification easier, as well as the aspiration of cortical material (soft part of the lens around the nucleus). (wikipedia.org)
  • pathology
  • A firm understanding of the embryology and development of the lens will provide great insight into the pathology associated with cataract formation. (utah.edu)
  • optic
  • Concurrently, the optic vesicles invaginate causing an indentation on the lens placode called the lens pit (Fig. 2a). (utah.edu)
  • The first stage of lens differentiation takes place when the optic vesicle, which is formed from outpocketings in the neural ectoderm, comes in proximity to the surface ectoderm. (wikipedia.org)
  • Nuclei of the optic tract are involved in smooth pursuit eye movement and the accommodation reflex, as well as REM. (wikipedia.org)
  • epithelium
  • It is synthesized by the lens epithelium and its main components are Type IV collagen and sulfated glycosaminoglycans (GAGs). (wikipedia.org)
  • The cells of the lens epithelium regulate most of the homeostatic functions of the lens. (wikipedia.org)
  • humans
  • Mammals, birds and reptiles vary the optical power by changing the form of the elastic lens using the ciliary body (in humans up to 15 dioptres). (wikipedia.org)
  • dense
  • As successive layers continue to be deposited, the lens becomes so dense that it begins to change color and the clarity is lost. (google.com)
  • The inner nucleus of the cataract consists of a firm, dense material while the outer nucleus consists of a less dense material. (google.com)
  • Compared to terrestrial vertebrates, fish lenses are generally more dense and spherical. (wikipedia.org)
  • ciliary
  • When the ciliary muscle, which is located within the ciliary body, contracts, tension on the zonules is altered, resulting in a change in the shape of the lens. (medscape.com)
  • There are 2 different theories on how ciliary muscle contraction alters zonular tension to increase the optical power of the lens during accommodation. (medscape.com)
  • [ 6 ] , and finite element and mathematical analysis demonstrates that the ciliary muscle would have to apply more force than is physiologically possible to simultaneously flatten the central and peripheral lens surfaces for distance vision. (medscape.com)
  • Finally the lens is pinched off and settles in place with the developing iris and ciliary body in the front of the eyeball (3). (utah.edu)
  • When viewing a far object, the circularly arranged ciliary muscle relaxes allowing the lens zonules and suspensory ligaments to pull on the lens, flattening it. (wikipedia.org)
  • When viewing a near object, the ciliary muscles contract (resisting the outward pressure on the sclera) causing the lens zonules to slacken which allows the lens to spring back into a thicker, more convex, form. (wikipedia.org)
  • The ciliary body thus directs the shape like the pylons of a suspension bridge, but does not need to support an equatorial traction force to flatten the lens. (wikipedia.org)
  • cornea
  • Notice the lens is flatter anteriorally, facing the cornea (cornea). (utah.edu)
  • It involves manual expression of the lens through a large (usually 10-12 mm) incision made in the cornea or sclera. (wikipedia.org)
  • Light enters the eye at the cornea, passing through the pupil to reach the lens. (wikipedia.org)
  • In the aquatic environment there is not a major difference in the refractive index of the cornea and the surrounding water (compared to air on land) so the lens has to do the majority of the refraction. (wikipedia.org)
  • zonular
  • The increased equatorial zonular tension keeps the lens stable and flattens the peripheral lens surface during accommodation. (wikipedia.org)
  • radiation
  • What exactly does radiation do to the lens of the eye to make it cloudy? (nasa.gov)
  • In this study, we investigated the relationship between the biomechanical properties of the crystalline lens and intraocular pressure (IOP) using a confocal acoustic radiation force (ARF) and phase-sensitive optical coherence elastography (OCE) system. (osapublishing.org)
  • Employing shorter wavelengths implied abandoning microscopy and true imaging, however, because there exists no material from which a lens capable of focusing this type of radiation can be created. (wikipedia.org)
  • bifocal
  • bifocal lens one having two segments with different refracting power, the upper for far vision and the lower for near vision. (thefreedictionary.com)
  • omnifocal lens one whose power increases continuously and regularly in a downward direction, avoiding the discontinuity in field and power inherent in bifocal and trifocal lenses . (thefreedictionary.com)
  • The age-related decline in accommodation occurs almost universally to less than 2 dioptres by the time a person reaches 45 to 50 years, by which time most of the population will have noticed a decrease in their ability to focus on close objects and hence require glasses for reading or bifocal lenses. (wikipedia.org)
  • fragmentation
  • However, new laser platforms have been developed which enable this femtosecond laser to operate in a similar fashion to perform lens fragmentation, anterior capsulorrhexis and corneal or limbal incisions at the time of cataract extraction. (thefreedictionary.com)
  • outer
  • The terms hydrodelineation, hydrodelamination, and hydrodemarcation are all synonymous and refer to the injection of fluid within the body of the cataract to separate the inner nucleus from the outer nucleus. (google.com)
  • thickness
  • Anterior chamber depth (ACD), anterior chamber area (ACA), iris thickness, iris area, iris curvature, lens vault, angle opening distance (AOD500, AOD750) and trabecular iris space area (TISA500, TISA750) were measured in qualified images using the Zhongshan Angle Assessment Program and compared preoperatively and 3 months postoperatively. (bmj.com)
  • confocal
  • LEC migration, DNA fragment, free DNA retention, and reactive oxygen species (ROS) presence were established in the living lenses with fluorescent dyes using laser scanning confocal microscopy (LSCM). (nih.gov)
  • adjustment
  • This adjustment of the lens is known as accommodation (similar to the focusing of a photographic camera via movement of its lenses ). (utah.edu)
  • This adjustment of the lens is known as accommodation (see also below). (wikipedia.org)
  • anterior
  • cutting means extending perpendicular from said rotary means and distant from said piercing means for making a circular incision in the anterior surface of said lens substantially concentric about said piercing means. (google.co.uk)
  • Anterior, posterior and medial pretectal nuclei inhibit pain (indirectly), aid in REM, and aid the accommodation reflex, respectively. (wikipedia.org)
  • The anterior visual pathway refers to structures involved in vision before the lateral geniculate nucleus. (wikipedia.org)
  • that when the ciliary muscle contracts, equatorial zonular tension is increased, causing the central surfaces of the crystalline lens to steepen, the central thickness of the lens to increase (anterior-posterior diameter), and the peripheral surfaces of the lens to flatten. (wikipedia.org)
  • Catenary-D. Jackson Coleman proposes that the lens, zonule and anterior vitreous comprise a diaphragm between the anterior and vitreous chambers of the eye. (wikipedia.org)
  • Ciliary muscle contraction initiates a pressure gradient between the vitreous and aqueous compartments that support the anterior lens shape in the mechanically reproducible state of a steep radius of curvature in the center of the lens with slight flattening of the peripheral anterior lens, i.e. the shape, in cross section, of a catenary. (wikipedia.org)
  • cataract
  • This approach is contrasted with intracapsular cataract extraction (ICCE), an older procedure in which the surgeon removed the complete lens within its capsule and left the eye aphakic (without a lens). (encyclopedia.com)
  • After von Graefe, however, intracapsular extraction gradually became the favored method of cataract removal even though it left the patient without a lens inside the eye. (encyclopedia.com)
  • To understand cataract surgery, it is helpful to have a basic description of the structure of the lens in the human eye. (encyclopedia.com)
  • A cataract is a cloudy area in the lens of the eye. (avclinic.com)
  • The way to surgically treat a cataract is to remove the lens and replace it with an artificial lens called an implant (See photo). (avclinic.com)
  • Your doctor will discuss the options with you before choosing the best kind of cataract removal and lens replacement for you. (avclinic.com)
  • sclera
  • When viewing a near object, the ciliary muscles contract (resisting the outward pressure on the sclera) causing the lens zonules to slacken which allows the lens to spring back into a thicker, more convex, form. (wikipedia.org)
  • electrodes
  • The instruments consisted of bilaterally implanted microelectrodes in the vestibular nuclei, and electro-oculogram and electroencephalogram electrodes. (wikipedia.org)
  • Disposable diapers where they absorb urine, or in sanitary napkins Contact lenses (silicone hydrogels, polyacrylamides, polymacon) EEG and ECG medical electrodes using hydrogels composed of cross-linked polymers (polyethylene oxide, polyAMPS and polyvinylpyrrolidone) Water gel explosives Rectal drug delivery and diagnosis Encapsulation of quantum dots Breast implants Glue Granules for holding soil moisture in arid areas Dressings for healing of burn or other hard-to-heal wounds. (wikipedia.org)
  • convergence
  • The combination of these three movements (accommodation, convergence and miosis) is under the control of the Edinger-Westphal nucleus and is referred to as the near triad, or accommodation reflex. (wikipedia.org)
  • form
  • The crystalline form of calcium carbonate or nacre, aragonite is composed of tiny, microns-thin crystal platelets that are mostly translucent which are capable of reflecting and dispersing light waves into their rainbow spectrum. (adiamor.com)
  • These proteins, when expressed at low levels in many tissues function as enzymes, but when expressed at high levels in eye tissue, become densely packed and thus form lenses. (wikipedia.org)
  • Due to "a refractive index gradient within the lens - exactly as one would expect from optical theory" the spherical lenses of fish are able to form sharp images free from spherical aberration. (wikipedia.org)
  • Alpha-enolase, in addition, functions as a structural lens protein (tau-crystallin) in the monomeric form. (wikipedia.org)
  • Within cells, ENO1 predominantly localizes to the cytoplasm, though an alternatively translated form is localizes to the nucleus. (wikipedia.org)
  • focus
  • The age-related decline in accommodation occurs almost universally to less than 2 dioptres by the time a person reaches 45 to 50 years, by which time most of the population will have noticed a decrease in their ability to focus on close objects and hence require glasses for reading or bifocal lenses. (wikipedia.org)
  • vision
  • The patient's vision was corrected after intracapsular extraction by extremely thick eyeglasses or by contact lenses. (encyclopedia.com)
  • The purpose of ECCE is to restore clear vision by removing a clouded or discolored lens and replacing it with an IOL. (encyclopedia.com)
  • A change in your glasses, stronger bifocals, or the use of magnifying lenses may help improve your vision and be treatment enough. (avclinic.com)
  • A third type, melanopsin in some of the retinal ganglion cells (RGC), part of the body clock mechanism, is probably not involved in conscious vision, as these RGC do not project to the lateral geniculate nucleus but to the pretectal olivary nucleus. (wikipedia.org)
  • Fernald also did research on eye evolution, showing that photoreceptor proteins have an ancient origin predating vision while lens proteins have arisen many times from different sources in different animal lineages. (wikipedia.org)
  • made
  • Both mirrors are made from a crystalline ceramic material called Sitall, chosen for its low coefficient of thermal expansion. (wikipedia.org)
  • optical
  • Unless there are complications (e.g. secondary glaucoma) or monocular diplopia the lens is left in place and management is optical. (thefreedictionary.com)
  • Also in the primary mirror cell is another instrument able to modify the telescope's optical configuration by moving from a corrector composed by a double set of lenses, to an atmospheric dispersion corrector (ADC) composed of a counter-rotating set of prisms, able to correct the optical dispersion phenomena due to the variation of air mass induced by changing the altitude angle. (wikipedia.org)
  • eyes
  • Fish eyes are similar to the eyes of terrestrial vertebrates like birds and mammals, but have a more spherical lens. (wikipedia.org)
  • fish
  • Compared to terrestrial vertebrates, fish lenses are generally more dense and spherical. (wikipedia.org)
  • Fernald next asked how fish lens quality was preserved during growth, identifying specific mechanisms, sharing the Rank Prize for the discovery. (wikipedia.org)
  • material
  • An organogel is a non-crystalline, non-glassy thermoreversible (thermoplastic) solid material composed of a liquid organic phase entrapped in a three-dimensionally cross-linked network. (wikipedia.org)
  • functions
  • Piatigorsky determined that lens crystallin conservation and variance is due to other moonlighting functions outside of the lens. (wikipedia.org)
  • object
  • When viewing a far object, the circularly arranged ciliary muscle relaxes allowing the lens zonules and suspensory ligaments to pull on the lens, flattening it. (wikipedia.org)