An area approximately 1.5 millimeters in diameter within the macula lutea where the retina thins out greatly because of the oblique shifting of all layers except the pigment epithelium layer. It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the cones most adapted to yield high visual acuity, each cone being connected to only one ganglion cell. (Cline et al., Dictionary of Visual Science, 4th ed)
The only family of the order SCANDENTIA, variously included in the order Insectivora or in the order Primates, and often in the order Microscelidea, consisting of five genera. They are TUPAIA, Ananthana (Indian tree shrew), Dendrogale (small smooth-tailed tree shrew), Urogale (Mindanao tree shrew), and Ptilocercus (pen-tailed tree shrew). The tree shrews inhabit the forest areas of eastern Asia from India and southwestern China to Borneo and the Philippines.
Clusters of neurons in the somatic peripheral nervous system which contain the cell bodies of sensory nerve axons. Sensory ganglia may also have intrinsic interneurons and non-neuronal supporting cells.
A family of the New World monkeys inhabiting the forests of South and Central America. There is a single genus and several species occurring in this family, including AOTUS TRIVIRGATUS (Northern night monkeys).
Photosensitive proteins expressed in the CONE PHOTORECEPTOR CELLS. They are the protein components of cone photopigments. Cone opsins are classified by their peak absorption wavelengths.
The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)
Infection with flukes of the genus Dicrocoelium.
A genus of trematode liver flukes of the family Dicrocoeliidae which includes the species dendriticum and hospes. It occurs in the biliary passages or liver of many vertebrates including man. The intermediate hosts are mainly mollusks but occasionally ants.
The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
An oval area in the retina, 3 to 5 mm in diameter, usually located temporal to the posterior pole of the eye and slightly below the level of the optic disk. It is characterized by the presence of a yellow pigment diffusely permeating the inner layers, contains the fovea centralis in its center, and provides the best phototropic visual acuity. It is devoid of retinal blood vessels, except in its periphery, and receives nourishment from the choriocapillaris of the choroid. (From Cline et al., Dictionary of Visual Science, 4th ed)
Neurons of the innermost layer of the retina, the internal plexiform layer. They are of variable sizes and shapes, and their axons project via the OPTIC NERVE to the brain. A small subset of these cells act as photoreceptors with projections to the SUPRACHIASMATIC NUCLEUS, the center for regulating CIRCADIAN RHYTHM.
Neurons which send impulses peripherally to activate muscles or secretory cells.
The total area or space visible in a person's peripheral vision with the eye looking straightforward.
The number of CELLS of a specific kind, usually measured per unit volume or area of sample.
Specialized cells that detect and transduce light. They are classified into two types based on their light reception structure, the ciliary photoreceptors and the rhabdomeric photoreceptors with MICROVILLI. Ciliary photoreceptor cells use OPSINS that activate a PHOSPHODIESTERASE phosphodiesterase cascade. Rhabdomeric photoreceptor cells use opsins that activate a PHOSPHOLIPASE C cascade.
Photosensitive afferent neurons located in the peripheral retina, with their density increases radially away from the FOVEA CENTRALIS. Being much more sensitive to light than the RETINAL CONE CELLS, the rod cells are responsible for twilight vision (at scotopic intensities) as well as peripheral vision, but provide no color discrimination.
The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.
An imaging method using LASERS that is used for mapping subsurface structure. When a reflective site in the sample is at the same optical path length (coherence) as the reference mirror, the detector observes interference fringes.
The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.
Photosensitive afferent neurons located primarily within the FOVEA CENTRALIS of the MACULA LUTEA. There are three major types of cone cells (red, blue, and green) whose photopigments have different spectral sensitivity curves. Retinal cone cells operate in daylight vision (at photopic intensities) providing color recognition and central visual acuity.
Clarity or sharpness of OCULAR VISION or the ability of the eye to see fine details. Visual acuity depends on the functions of RETINA, neuronal transmission, and the interpretative ability of the brain. Normal visual acuity is expressed as 20/20 indicating that one can see at 20 feet what should normally be seen at that distance. Visual acuity can also be influenced by brightness, color, and contrast.
The concave interior of the eye, consisting of the retina, the choroid, the sclera, the optic disk, and blood vessels, seen by means of the ophthalmoscope. (Cline et al., Dictionary of Visual Science, 4th ed)
Visualization of a vascular system after intravenous injection of a fluorescein solution. The images may be photographed or televised. It is used especially in studying the retinal and uveal vasculature.
The thin, highly vascular membrane covering most of the posterior of the eye between the RETINA and SCLERA.
Photosensitive protein complexes of varied light absorption properties which are expressed in the PHOTORECEPTOR CELLS. They are OPSINS conjugated with VITAMIN A-based chromophores. Chromophores capture photons of light, leading to the activation of opsins and a biochemical cascade that ultimately excites the photoreceptor cells.
Examination of the interior of the eye with an ophthalmoscope.
BIRDS that hunt and kill other animals, especially higher vertebrates, for food. They include the FALCONIFORMES order, or diurnal birds of prey, comprised of EAGLES, falcons, HAWKS, and others, as well as the STRIGIFORMES order, or nocturnal birds of prey, which includes OWLS.
Devices for examining the interior of the eye, permitting the clear visualization of the structures of the eye at any depth. (UMDNS, 1999)
A localized defect in the visual field bordered by an area of normal vision. This occurs with a variety of EYE DISEASES (e.g., RETINAL DISEASES and GLAUCOMA); OPTIC NERVE DISEASES, and other conditions.
The positioning and accommodation of eyes that allows the image to be brought into place on the FOVEA CENTRALIS of each eye.
The minimum amount of stimulus energy necessary to elicit a sensory response.
Large members of the FALCONIFORMES order of birds, family Accipitridae, most especially the genera Aquila, Haliaeetus, Harpia, and Circaetus. They are characterized by their powerful talons, which carry long, curved, pointed claws and by their opposable hindtoe.
An objective determination of the refractive state of the eye (NEARSIGHTEDNESS; FARSIGHTEDNESS; ASTIGMATISM). By using a RETINOSCOPE, the amount of correction and the power of lens needed can be determined.
Any of numerous burrowing mammals found in temperate regions and having minute eyes often covered with skin.
Perforations through the whole thickness of the retina including the macula as the result of inflammation, trauma, degeneration, etc. The concept includes retinal breaks, tears, dialyses, and holes.
The ability to detect sharp boundaries (stimuli) and to detect slight changes in luminance at regions without distinct contours. Psychophysical measurements of this visual function are used to evaluate visual acuity and to detect eye disease.
General disorders of the sclera or white of the eye. They may include anatomic, embryologic, degenerative, or pigmentation defects.
Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.
Method of making images on a sensitized surface by exposure to light or other radiant energy.
The process in which light signals are transformed by the PHOTORECEPTOR CELLS into electrical signals which can then be transmitted to the brain.
Defects of color vision are mainly hereditary traits but can be secondary to acquired or developmental abnormalities in the CONES (RETINA). Severity of hereditary defects of color vision depends on the degree of mutation of the ROD OPSINS genes (on X CHROMOSOME and CHROMOSOME 3) that code the photopigments for red, green and blue.
Degenerative changes in the RETINA usually of older adults which results in a loss of vision in the center of the visual field (the MACULA LUTEA) because of damage to the retina. It occurs in dry and wet forms.
The science dealing with the correlation of the physical characteristics of a stimulus, e.g., frequency or intensity, with the response to the stimulus, in order to assess the psychologic factors involved in the relationship.
Retinal diseases refer to medical conditions that affect the retina, the light-sensitive tissue at the back of the eye, leading to vision loss or blindness.
Method of measuring and mapping the scope of vision, from central to peripheral of each eye.
Visual sensation derived from sensory stimulation by objects or shadows inside the eye itself, such as floating vitreous fibers, tissues, or blood.
Excessive axial myopia associated with complications (especially posterior staphyloma and CHOROIDAL NEOVASCULARIZATION) that can lead to BLINDNESS.
A membrane on the vitreal surface of the retina resulting from the proliferation of one or more of three retinal elements: (1) fibrous astrocytes; (2) fibrocytes; and (3) retinal pigment epithelial cells. Localized epiretinal membranes may occur at the posterior pole of the eye without clinical signs or may cause marked loss of vision as a result of covering, distorting, or detaching the fovea centralis. Epiretinal membranes may cause vascular leakage and secondary retinal edema. In younger individuals some membranes appear to be developmental in origin and occur in otherwise normal eyes. The majority occur in association with retinal holes, ocular concussions, retinal inflammation, or after ocular surgery. (Newell, Ophthalmology: Principles and Concepts, 7th ed, p291)
Fluid accumulation in the outer layer of the MACULA LUTEA that results from intraocular or systemic insults. It may develop in a diffuse pattern where the macula appears thickened or it may acquire the characteristic petaloid appearance referred to as cystoid macular edema. Although macular edema may be associated with various underlying conditions, it is most commonly seen following intraocular surgery, venous occlusive disease, DIABETIC RETINOPATHY, and posterior segment inflammatory disease. (From Survey of Ophthalmology 2004; 49(5) 470-90)
The blood vessels which supply and drain the RETINA.
The portion of the optic nerve seen in the fundus with the ophthalmoscope. It is formed by the meeting of all the retinal ganglion cell axons as they enter the optic nerve.
A series of tests used to assess various functions of the eyes.
Recording of electric potentials in the retina after stimulation by light.
Specialized PHOTOTRANSDUCTION neurons in the vertebrates, such as the RETINAL ROD CELLS and the RETINAL CONE CELLS. Non-visual photoreceptor neurons have been reported in the deep brain, the PINEAL GLAND and organs of the circadian system.
A naturally occurring lipid pigment with histochemical characteristics similar to ceroid. It accumulates in various normal tissues and apparently increases in quantity with age.
Methods and procedures for the diagnosis of diseases of the eye or of vision disorders.
Detachment of the corpus vitreum (VITREOUS BODY) from its normal attachments, especially the retina, due to shrinkage from degenerative or inflammatory conditions, trauma, myopia, or senility.
The inner portion of a retinal rod or a cone photoreceptor cell, situated between the PHOTORECEPTOR CONNECTING CILIUM and the synapse with the adjacent neurons (RETINAL BIPOLAR CELLS; RETINAL HORIZONTAL CELLS). The inner segment contains the cell body, the nucleus, the mitochondria, and apparatus for protein synthesis.

Optical, receptoral, and retinal constraints on foveal and peripheral vision in the human neonate. (1/692)

We examined the properties of the foveal, parafoveal, and near peripheral cone lattice in human neonates. To estimate the ability of these lattices to transmit the information used in contrast sensitivity and visual acuity tasks, we constructed ideal-observer models with the optics and photoreceptors of the neonatal eye at retinal eccentricities of 0, 5, and 10 degrees. For ideal-observer models limited by photon noise, the eye's optics, and cone properties, contrast sensitivity was higher in the parafovea and near periphery than in the fovea. However, receptor pooling probably occurs in the neonate's parafovea and near periphery as it does in mature eyes. When we add a receptor-pooling stage to the models of the parafovea and near periphery, ideal acuity is similar in the fovea, parafovea, and near periphery. Comparisons of ideal and real sensitivity indicate that optical and receptoral immaturities impose a significant constraint on neonatal contrast sensitivity and acuity, but that immaturities in later processing stages must also limit visual performance.  (+info)

Radiotherapy for isolated occult subfoveal neovascularisation in age related macular degeneration: a pilot study. (2/692)

BACKGROUND/AIMS: Teletherapy has been proposed as a possible treatment for choroidal neovascular membranes (CNV), secondary to age related macular degeneration (AMD) not amenable to laser photocoagulation. The aim of this prospective study has been to investigate the effect of teletherapy on isolated occult choroidal neovascular membranes of subfoveal location. METHODS: 28 AMD patients presenting with retrofoveal isolated occult CNV demonstrated by fluorescein angiography were treated by external beam radiation. A complete ophthalmological examination, fluorescein angiography, and indocyanine green angiography (ICG) were performed within 15 days before treatment and repeated at follow up. A total dose of 16 Gy was applied in four sessions of 4 Gy using a 4 MeV photon beam. Follow up ranged from 6 to 9 months (mean follow up 6.4 months). RESULTS: Visual acuity was found to be stable in 68% of the cases. The decrease in visual acuity was of 3-6 lines in 18% and of more than 6 lines in 10% of the eyes at last examination. On fluorescein angiography the size of the lesion area was found to be stable in 67%, decreased in 13%, and increased in 20% of the cases. On ICG angiography the size of the CNV was stable in 93% and increased in 7% of the cases. All the eyes experiencing a visual acuity decrease showed either no change or an increase in size of the membrane on fluorescein angiography and/or on ICG. CONCLUSION: According to this study with strict inclusion criteria, external beam radiotherapy seems to have a beneficial effect on the evolution of isolated occult subfoveal CNV.  (+info)

Contour integration in the peripheral field. (3/692)

Contour integration was measured in the normal peripheral field to determine if an explanation based solely on the known peripheral positional uncertainty was sufficient to explain performance. The task involved the detection of paths composed of micropatterns with correlated carrier orientations embedded in a field of similar micropatterns of random position and orientation (Field, D. J., Hayes A., & Hess, R. F. (1993). Vision Research, 33, 173-193). The intrinsic positional uncertainty for each eccentric locus was measured with the same stimulus and it did not account for levels of peripheral performance. We show that peripheral performance on this task does not get worse with eccentricity beyond about 10 degrees and that these results can be modeled by simple filtering without any subsequent cellular linking interactions.  (+info)

The effects of temporal noise and retinal illuminance on foveal flicker sensitivity. (4/692)

We measured foveal flicker sensitivity with and without external added temporal noise at various levels of retinal illuminance and described the data with our model of flicker sensitivity comprising: (i) low-pass filtering of the flickering signal plus external temporal and/or quantal noise by the modulation transfer function (MTF) of the retina (R): (ii) high-pass filtering in proportion to temporal frequency by the MTF of the postreceptoral neural pathways (P): (iii) addition of internal white neural noise; and (iv) detection by a temporal matched filter. Without temporal noise flicker sensitivity had a band-pass frequency-dependence at high and medium illuminances but changed towards a low-pass shape above 0.5 Hz at low luminances, in agreement with earlier studies. In strong external temporal noise, however, the flicker sensitivity function had a low-pass shape even at high and medium illuminances and flicker sensitivity was consistently lower with noise than without. At low luminances flicker sensitivity was similar with and without noise. An excellent fit of the model was obtained under the assumption that the only luminance-dependent changes were increases in the cut-off frequency (fc) and maximum contrast transfer of R with increasing luminance. The results imply the following: (i) performance is consistent with detection by a temporal matched filter, but not with a thresholding process based on signal amplitude; (ii) quantal fluctuations do not at any luminance level become a source of dominant noise present at the detector; (iii) the changes in the maximum contrast transfer reflect changes in retinal gain, which at low to moderate luminances implement less-than-Weber adaptation, with a 'square-root' law at the lowest levels; (iv) the changes of fc as function of mean luminance closely parallels time scale changes in cones, but the absolute values of fc are lower than expected from the kinetics of monkey cones at all luminances; (v) the constancy of the high-pass filtering function P indicates that surround antagonism does not weaken significantly with decreasing light level.  (+info)

Eye movements of rhesus monkeys directed towards imaginary targets. (5/692)

Is the presence of foveal stimulation a necessary prerequisite for rhesus monkeys to perform visually guided eye movements? To answer this question, we trained two rhesus monkeys to direct their eyes towards imaginary targets defined by extrafoveal cues. Independent of the type of target, real or imaginary, the trajectory of target movement determined the type of eye movement produced: steps in target position resulted in saccades and ramps in target position resulted in smooth pursuit eye movements. There was a tendency for the latency of saccades as well as pursuit onset latency to be delayed in the case of an imaginary target in comparison to the real target. The initial eye acceleration during smooth pursuit initiation elicited by an imaginary target decreased in comparison to the acceleration elicited by a real target. The steady-state pursuit gain was quite similar during pursuit of an imaginary or a real target. Our results strengthen the notion that pursuit is not exclusively a foveal function.  (+info)

Peripheral vision and oculomotor control during visual search. (6/692)

The present study concerns the dynamics of multiple fixation search. We tried to gain insight into: (1) how the peripheral and foveal stimulus affect fixation duration; and (2) how fixation duration affects the peripheral target selection for saccades. We replicated the non-corroborating results of Luria and Strauss (1975) ('Eye movements during search for coded and uncoded targets', Perception and Psychophysics 17, 303-308) (saccades were selective), and Zelinsky (1996) (Using eye movements to assess the selectivity of search movements. Vision research 36(14), 2177-2187) (saccades were not selective), by manipulating the critical features for peripheral selection and discrimination separately. We found search to be more selective and efficient when the selection task was easy or when fixations were long-lasting. Remarkably, subjects did not increase their fixation durations when the peripheral selection task was more difficult. Only the discrimination task affected the fixation duration. This implies that the time available for peripheral target selection is determined mainly by the discrimination task. The results of the present experiment suggest that, besides the difficulty of the peripheral selection task, fixation duration is an important factor determining the selection of potential targets for eye movements.  (+info)

Contrast dependency of foveal spatial functions: orientation, vernier, separation, blur and displacement discrimination and the tilt and Poggendorff illusions. (7/692)

To examine the effect of reducing luminance contrast in human foveal vision, discrimination thresholds were measured in four tasks and also a numerical measure of two visual illusions were obtained by a nulling technique. The patterns used for all tasks were made very similar to facilitate comparison between them--all featured luminance step edges whose contrast could be varied from near unity down to the detection threshold. Orientation, vernier and blur discrimination thresholds rise on average 5-6-fold when the contrast is reduced from near unity to a Michelson value of 0.03. Jump displacement thresholds are somewhat more robust to contrast reduction, and the curve of separation discrimination versus contrast is much shallower, rising by a factor of about 2. The magnitude of the Poggendorff and tilt illusions changes very little until the inducing contours are barely detectable.  (+info)

Temporal resolution deficits in the visual fields of MS patients. (8/692)

We assessed the relationship between temporal resolution and MS-induced neuropathy. A diagnostic strategy comprising assessments of temporal resolution at 16 points in the extra-foveal visual field up to 12 degrees from the fovea was first compared with foveal temporal resolution and with a standard VEP procedure in the same MS patients. At the group level, foveal temporal resolution was less sensitive to demyelination than the 16-point diagnostic strategy, the detection rate of which was comparable to that of the VEP procedure. Cross-sensitivity of the VEP and the 16-point diagnostic procedure was low. Subsequently, the average severity of MS-induced temporal resolution deficits was studied at three retinal loci of the same size but different eccentricities. Foveal deficits were not significantly greater than more peripheral deficits within the central 12 degrees.  (+info)

I'm sorry, but I couldn't find any information on a medical term called "Aotidae." It's possible that you may have misspelled the term or that it is not commonly used in the medical field. If you could provide more context or information about where you heard or saw this term, I may be able to assist you further.

Cone opsins are a type of photopigment found in the retina of the eye. They are responsible for detecting light and color in the visible spectrum. There are three types of cone opsins, each of which is sensitive to different wavelengths of light: short-wavelength (S-cone), medium-wavelength (M-cone), and long-wavelength (L-cone) cone opsins. These cone opsins work together to allow humans to perceive a wide range of colors and shades.

In the medical field, "cats" typically refers to Felis catus, which is the scientific name for the domestic cat. Cats are commonly kept as pets and are known for their agility, playful behavior, and affectionate nature. In veterinary medicine, cats are commonly treated for a variety of health conditions, including respiratory infections, urinary tract infections, gastrointestinal issues, and dental problems. Cats can also be used in medical research to study various diseases and conditions, such as cancer, heart disease, and neurological disorders. In some cases, the term "cats" may also refer to a group of animals used in medical research or testing. For example, cats may be used to study the effects of certain drugs or treatments on the immune system or to test new vaccines.

Dicrocoeliasis is a parasitic infection caused by the liver fluke Dicrocoelium dendriticum. The infection is found in many parts of the world, particularly in areas where grazing animals such as sheep, goats, and cattle are raised. The fluke infects the liver of the animal, causing damage and potentially leading to liver failure. In humans, the infection is rare and typically occurs when people consume raw or undercooked meat from infected animals. Symptoms of dicrocoeliasis in humans may include abdominal pain, fever, and jaundice. Treatment typically involves the use of antiparasitic medications.

In the medical field, "cell count" refers to the measurement of the number of cells present in a specific sample of tissue or fluid. This measurement is typically performed using a microscope and a specialized staining technique to distinguish between different types of cells. For example, a complete blood count (CBC) is a common laboratory test that measures the number and types of cells in the blood, including red blood cells, white blood cells, and platelets. Similarly, a urine analysis may include a cell count to measure the number of white blood cells or bacteria present in the urine. Cell counts can be used to diagnose a variety of medical conditions, such as infections, inflammation, or cancer. They can also be used to monitor the effectiveness of treatments or to detect any changes in the body's cellular makeup over time.

The choroid is a layer of blood vessels and connective tissue located between the retina and the sclera of the eye. It is responsible for providing oxygen and nutrients to the retina, and for removing waste products from the retina. The choroid is also involved in regulating the amount of light that enters the eye and in maintaining the shape of the eye. In some cases, abnormalities in the choroid can lead to vision problems or other eye disorders.

In the medical field, a scotoma refers to a visual field defect or loss of vision in a specific area of the visual field. It is typically caused by damage to the retina, optic nerve, or other structures in the eye that are responsible for transmitting visual information to the brain. Scotomas can be classified as central or peripheral, depending on the location of the visual field loss. Central scotomas involve a loss of vision in the center of the visual field, while peripheral scotomas involve a loss of vision in the outer edges of the visual field. Scotomas can be caused by a variety of conditions, including glaucoma, diabetic retinopathy, macular degeneration, and optic neuritis. Treatment for scotomas depends on the underlying cause and may include medications, surgery, or other interventions to slow or stop the progression of the underlying condition.

Retinal Perforations refer to a hole or tear in the retina, which is the light-sensitive layer of tissue at the back of the eye. This can occur due to various reasons such as trauma, high blood pressure, or eye infections. Retinal Perforations can lead to a condition called retinal detachment, which is a serious medical emergency that requires prompt medical attention. Retinal detachment occurs when the retina separates from the underlying tissue, causing vision loss and potentially permanent damage to the eye. Treatment for Retinal Perforations may include surgery to repair the tear or hole in the retina, as well as medications to manage any underlying conditions that may have contributed to the perforation.

Contrast sensitivity is a measure of the ability of the human eye to distinguish between different levels of brightness or intensity in an image. It is an important aspect of visual function and is often used to assess the quality of vision in individuals with various eye conditions, such as cataracts, glaucoma, and age-related macular degeneration. In a contrast sensitivity test, the patient is shown a series of visual stimuli that vary in contrast, and asked to identify the orientation or shape of the stimuli. The test is typically performed under standardized conditions, such as a specific brightness level and viewing distance, to ensure that the results are accurate and reliable. The results of a contrast sensitivity test can provide valuable information about the patient's visual function and can help guide treatment decisions. For example, if a patient has low contrast sensitivity, it may indicate that they are having difficulty seeing details in low light conditions or when viewing objects against a complex background. This information can be used to recommend corrective lenses, such as high-contrast glasses, or to suggest further testing to identify and treat any underlying eye conditions.

Scleral diseases refer to disorders that affect the sclera, which is the white, tough outer layer of the eye. The sclera provides structural support to the eye and helps to maintain its shape. Scleral diseases can be classified into several categories, including inflammatory, infectious, neoplastic, and degenerative diseases. Some examples of scleral diseases include: 1. Scleritis: Inflammation of the sclera that can cause pain, redness, and sensitivity to light. 2. Scleromalacia perforans: A rare condition in which the sclera becomes thin and weak, leading to the formation of small holes. 3. Scleroma: A chronic inflammatory disease that affects the sclera and other connective tissues in the body. 4. Scleroderma: A connective tissue disorder that affects the skin, blood vessels, and internal organs, including the sclera. 5. Sclerotic keratitis: A rare condition in which the sclera becomes thickened and opaque, leading to vision loss. 6. Sclerotic glaucoma: A type of glaucoma that is caused by the thickening of the sclera, which can block the flow of aqueous humor out of the eye. Treatment for scleral diseases depends on the specific condition and its severity. In some cases, medications may be used to reduce inflammation or manage symptoms. In more severe cases, surgery may be necessary to repair or replace damaged tissue.

Color vision defects, also known as color blindness, are conditions in which an individual has difficulty distinguishing between certain colors or perceiving colors in a different way than others. This can be caused by a variety of factors, including genetic mutations, eye diseases, exposure to certain chemicals or toxins, and head injuries. There are several different types of color vision defects, including red-green color blindness, blue-yellow color blindness, and total color blindness. Red-green color blindness is the most common type, and it affects the ability to distinguish between red and green colors. Blue-yellow color blindness affects the ability to distinguish between blue and yellow colors, while total color blindness, also known as achromatopsia, affects the ability to see any colors at all. Color vision defects can have a significant impact on an individual's daily life, as they can make it difficult to perform certain tasks, such as driving, reading, or identifying certain types of materials. In some cases, color vision defects may also be a sign of an underlying medical condition, such as a retinal disease or a neurological disorder, and it is important for individuals with color vision defects to see an eye doctor for a proper diagnosis and treatment.

Macular degeneration is a medical condition that affects the macula, which is the central part of the retina in the eye responsible for sharp, central vision. There are two main types of macular degeneration: dry and wet. Dry macular degeneration is the most common form and is characterized by the gradual accumulation of small yellow deposits called drusen in the macula. These deposits can cause the retina to thin and the macula to become damaged, leading to a loss of central vision. Wet macular degeneration is less common but more severe. It occurs when abnormal blood vessels grow beneath the retina and leak fluid or blood, causing damage to the macula and leading to a rapid loss of vision. Both forms of macular degeneration can be treated, but the best course of action depends on the severity of the condition and the individual patient's needs. Treatment options may include lifestyle changes, medications, or surgery.

Retinal diseases refer to a group of medical conditions that affect the retina, which is the light-sensitive layer of tissue at the back of the eye. The retina is responsible for converting light into electrical signals that are transmitted to the brain, where they are interpreted as visual images. Retinal diseases can affect any part of the retina, including the photoreceptor cells (rods and cones), the blood vessels, and the supporting cells. Some common types of retinal diseases include: 1. Age-related macular degeneration (AMD): A progressive disease that affects the central part of the retina, leading to vision loss. 2. Diabetic retinopathy: A complication of diabetes that can cause damage to the blood vessels in the retina, leading to vision loss. 3. Retinal detachment: A condition in which the retina separates from the underlying tissue, leading to vision loss if left untreated. 4. Retinitis pigmentosa: A group of inherited retinal diseases that cause progressive vision loss due to the death of photoreceptor cells. 5. Cataracts: A clouding of the lens in the eye that can cause vision loss. Retinal diseases can be treated with a variety of methods, including medication, laser therapy, surgery, and lifestyle changes. Early detection and treatment are crucial for preserving vision in people with retinal diseases.

Myopia, also known as nearsightedness, is a common eye condition in which a person can see objects clearly up close but has difficulty seeing objects that are far away. Degenerative myopia, also known as pathologic myopia, is a more severe form of myopia that is characterized by progressive eye growth and increased nearsightedness over time. This can lead to a variety of complications, including retinal detachment, glaucoma, and cataracts. Treatment for degenerative myopia may include glasses or contact lenses, as well as surgery to correct the vision.

An epiretinal membrane (ERM) is a thin, fibrous tissue that grows on the surface of the retina, the light-sensitive layer at the back of the eye. It is a common condition that can occur in people of all ages, but it is more common in older adults. ERM can cause a range of symptoms, including blurred vision, distorted vision, and the appearance of dark spots or "floaters" in the field of vision. In some cases, ERM can also cause vision loss if it thickens and pulls on the retina, causing it to detach. Treatment for ERM depends on the severity of the condition and the symptoms it is causing. In some cases, ERM may not cause any problems and may not require treatment. However, if ERM is causing significant vision loss or other symptoms, it may be treated with laser therapy or surgery to remove the membrane and restore normal vision.

Macular edema is a medical condition that occurs when there is fluid accumulation in the macula, which is the central part of the retina responsible for sharp, central vision. This fluid accumulation can cause swelling and damage to the macula, leading to vision loss or distortion. Macular edema can be caused by a variety of factors, including diabetes, high blood pressure, retinal vein occlusion, and age-related macular degeneration. It can also be a complication of certain eye surgeries or injuries. Treatment for macular edema depends on the underlying cause and severity of the condition. In some cases, medications such as anti-inflammatory drugs or steroids may be prescribed to reduce inflammation and swelling. Laser therapy or photodynamic therapy may also be used to treat certain types of macular edema. In severe cases, surgery may be necessary to remove the fluid and restore vision.

Lipofuscin is a yellow-brown, granular pigment that accumulates in cells over time, particularly in older cells. It is composed of oxidized lipids, proteins, and other cellular debris that have been broken down by enzymes. In the medical field, lipofuscin is often seen in various tissues and organs, particularly in the liver, spleen, and brain. It is a normal part of aging and is often associated with the accumulation of cellular waste products. However, excessive accumulation of lipofuscin has been linked to various diseases and conditions, including Alzheimer's disease, Parkinson's disease, and age-related macular degeneration. Lipofuscin accumulation can also be a sign of certain types of liver disease, such as non-alcoholic fatty liver disease and cirrhosis. In these cases, the accumulation of lipofuscin can be a marker of liver damage and can be used to monitor the progression of the disease.

Vitreous detachment is a condition in which the vitreous humor, a clear gel-like substance that fills the inside of the eye, separates from the retina, the light-sensitive layer at the back of the eye. This can occur as a result of aging, injury, or certain medical conditions such as diabetes or high blood pressure. Vitreous detachment is usually a benign condition and does not typically cause vision loss. However, in some cases, it can cause symptoms such as floaters, which are small specks or cobwebs that appear in the field of vision, or, which are brief flashes of light. In rare cases, a large detachment can cause a retinal tear or hole, which can lead to more serious vision problems. Treatment for vitreous detachment is typically not necessary unless it is causing significant symptoms or there is a risk of retinal detachment. In these cases, a doctor may recommend observation, medication, or surgery to repair the retinal tear or hole.

... and the perifovea is found at a 2.75 mm radius from the fovea centralis. The term fovea comes from Latin fovea 'pit'. The fovea ... GCL has >5 layers of cells, and highest density of cones Anatomical fovea / fovea centralis (clinical: macula) Area of ... fovea) Diameter = 0.35mm (about 1 deg of VF) the central floor of depression of fovea centralis 50 cones / 100 um Highest ... The fovea centralis is a small, central pit composed of closely packed cones in the eye. It is located in the center of the ...
In the fovea centralis, cones predominate and are present at high density. The macula is thus responsible for the central, high ... The umbo is the center of the foveola which in turn is located at the center of the fovea. The fovea is located near the center ... Fovea - 1.55 mm (0.061 in) Foveal avascular zone (FAZ) - 0.5 to 0.6 mm (0.020 to 0.024 in) Foveola - 0.35 mm (0.014 in) Umbo - ... Within the macula are the fovea and foveola that both contain a high density of cones, which are nerve cells that are ...
Gass, J. Donald M (1999). "Müller Cell Cone, an Overlooked Part of the Anatomy of the Fovea Centralis". Archives of ... Approximately 0.35 mm in diameter, the foveola lies in the center of the fovea and contains only cone cells and a cone-shaped ... Schematic diagram of the macula lutea of the retina, showing perifovea, parafovea, fovea, and clinical macula Time-Domain OCT ...
It describes the appearance of a small circular choroid shape as seen through the fovea centralis. Its appearance is due to a ...
Frontal-eyed animals have a small area of the retina with very high visual acuity, the fovea centralis. It covers about 2 ... To get a clear view of the world, the brain must turn the eyes so that the image of the object of regard falls on the fovea. ...
There are two to three rods per cone in the fovea centralis but five to six near the optic papilla. Cattle can distinguish long ...
At the "center" of the retina (the point directly behind the lens) lies the fovea (or fovea centralis), which contains only ... The distribution of cone classes (L, M, S) are also nonhomogenous, with no S-cones in the fovea, and the ratio of L-cones to M- ...
This area, termed the fovea centralis, is avascular (does not have blood vessels), and has minimal neural tissue in front of ... that possess no fovea, but a central band known as the visual streak.[citation needed] Around the fovea extends the central ... of axons in the optic nerve are devoted to the fovea. The resolution limit of the fovea has been determined to be around 10,000 ... The fovea produces the most accurate information. Despite occupying about 0.01% of the visual field (less than 2° of visual ...
Cone photoreceptors are concentrated in a depression in the center of the retina known as the fovea centralis and decrease in ... The fovea is blind to dim light (due to its cone-only array) and the rods are more sensitive, so a dim star on a moonless night ... rod photoreceptors are present at high density throughout the most of the retina with a sharp decline in the fovea. Perception ...
The foveal avascular zone (FAZ) is a region within the fovea centralis at the centre of the retina of the human eye that is ...
... move their entire eyes to focus images of interest onto their fovea centralis. In jumping spiders with a translucent carapace, ...
... centralis of the retina Fovea buccalis or Dimple Fovea of the femoral head Trochlear fovea of the frontal bone Pterygoid ... Look up fovea in Wiktionary, the free dictionary. Fovea (/ˈfoʊviə/) (Latin for "pit"; plural foveae /ˈfoʊvii/) is a term in ... Fovea (spider), a depression in the centre of the carapace Hilum, another term associated with anatomic pits or depressions ... fovea of the mandible neck fovea ethmoidalis part of the frontal bone of skull that separates ethmoid sinuses from the anterior ...
An issue that Kühne encountered when attempting to produce an image from a human eye is that the size of the fovea centralis, ...
A Palaeozoic Geology of London, Ontario (1974), Coach House Press Fovea Centralis (1975), Coach House Press Alter Sublime (1980 ...
... body Ciliary processes Ciliary muscle Iris Pupil Inner layer of eyeball Retina Ora serrata Optic disc Macula Fovea centralis ... Mandibular foramen Mandibular canal Mylohyoid groove Coronoid process Mandibular notch Condylar process Pterygoid fovea Hyoid ...
... fovea centralis MeSH A09.371.729.690 - optic disk MeSH A09.371.729.727 - photoreceptors MeSH A09.371.729.727.660 - ...
... specifically the Fovea centralis. These reactions are then passed as electrical signals through the optic nerve into the ...
Angular diameter Dioptre Eye examination Fovea centralis Golovin-Sivtsev table, for testing visual acuity Hyperacuity Landolt C ... To resolve detail, the eye's optical system has to project a focused image on the fovea, a region inside the macula having the ... The smallest cone cells in the fovea have sizes corresponding to 0.4 minarc of the visual field, which also places a lower ... Light travels from the fixation object to the fovea through an imaginary path called the visual axis. The eye's tissues and ...
... s are densely packed in the fovea centralis, a 0.3 mm diameter rod-free area with very thin, densely packed cones ... being smallest and most tightly packed at the center of the eye at the fovea. The S cone spacing is slightly larger than the ... but greatly outnumber rods in the fovea. Structurally, cone cells have a cone-like shape at one end where a pigment filters ...
Bruch's membrane Drusen Fovea centralis Fundus (eye) Macula of retina This article incorporates text in the public domain from ...
MWS and LWS cones are most responsible for visual acuity as they are concentrated in the fovea centralis region of the retina, ...
... macula and fovea centralis) as patients with these pathologies are often unable to fixate reliably. By contrast, fundus ...
... with the fovea slightly procurved. Its labium possesses no cuspules. A serrula is present, as is a small patch of teeth. Its ... "Acanthogonatus centralis". Integrated Taxonomic Information System. ADW entry "Acanthogonatus centralis" at the Encyclopedia of ... Acanthogonatus centralis is a mygalomorph spider of Argentina, its name referring to its distribution, being one of the most ... 224." (1995). Ferretti, Nelson; Pompozzi, Gabriel; Pérez-Miles, Fernando (2011). "Sexual behavior of Acanthogonatus centralis ( ...
Towards the centre of the retina is the fovea (or the less specialised, area centralis) which has a greater density of ... Many raptors have foveas with far more rods and cones than the human fovea (65,000/mm2 in American kestrel, 38,000 in humans) ... Because the image can be centered on the deep fovea of only one eye at a time, most falcons when diving use a spiral path to ... The forward-facing eyes of a bird of prey give binocular vision, which is assisted by a double fovea. The raptor's adaptations ...
Although they lack a fovea, some diurnal lemurs have a cone-rich, although less clustered, area centralis. This area centralis ... allowing for the evolution of the fovea. With only a postorbital bar, lemurs have been unable to develop a fovea. Therefore, ... The fovea on the retina, which yields higher visual acuity, is not well-developed. The postorbital septum (or bony closure ... whereas diurnal anthropoids have no rod cells in their fovea. Once again, this suggests lower visual acuity in lemurs than in ...
... and it has a procurved fovea. Its labium possesses no cuspules. A serrula is present. Its sternal sigilla is as in A. Centralis ... Females are most similar to those of A. centralis, but are distinguished by the narrow fundus of the spermathecae. Female: ... fovea width 0.67 millimetres (0.026 in); medial ocular quadrangle length 0.67 millimetres (0.026 in), width 1.28 millimetres ( ...
... its fovea is sinuous, procurved and without a posterior notch. Its labium possesses 3 cuspules. A serrula is present and well ... centralis and A. parana, which have - unlike A. Confusus - no inferior tarsal claws on tarsus IV). Female: total length 24.6 ... fovea width 0.9 millimetres (0.035 in); labium length 1.12 millimetres (0.044 in), width 1.62 millimetres (0.064 in); sternum ...
... "area centralis": a central patch with up to three times the density of nerve endings as the visual streak, giving them detailed ... a high density of rods in the fovea, an increased flicker rate, and a tapetum lucidum. The tapetum is a reflective surface ...
1856 c g Empis fovea Saigusa, 1964 c g Empis frauscheri Strobl, 1901 c g Empis freidbergi Chvála, 1999 c g Empis freyi Yang, ... 1867 c g Empis centralis Brunetti, 1913 c g Empis cetywayoi Smith, 1969 c g Empis ceylonica Bezzi, 1904 c g Empis cherskii ...
Some areas have higher densities of cone cells, for example (see fovea). Fish may have two or three areas specialised for high ... Miyazaki, T; Iwamu, T; Meyer-Rochow, VB (2011). "The position of the retinal area centralis changes with age in Champsocephalus ...
All photos and videos on this site belong to the National Eye Institute (NEI). Please credit ©NEI when you use any image or video from the library ...
Fovea Centralis. The fovea centralis, a small avascular depression at the center of the inner retinal surface filled with ... What Cajal did not realize was that, in order to maintain such visual acuity, each cone cell in the fovea is actually connected ... Signals from the fovea constitute half of all input to the visual cortex. ... In addition, information transmitted from the fovea to the visual cortex also contributes to color vision. ...
fovea centralis 743.55. *. gallbladder 751.69. *. Gartners duct 752.89. *. gastrointestinal tract 751.8. *. genitalia, genital ...
Categories: Fovea Centralis Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted 5 ...
Type I: Posterior dislocation of the hip with fracture of the femoral head caudad to the fovea centralis. Type II: Posterior ... dislocation of the hip with fracture of the femoral head cephalad to the fovea centralis. ...
Fovea Centralis Actions. * Search in PubMed * Search in MeSH * Add to Search ...
In the posterior pole, a shallow depression is termed the fovea centralis (see the following image). This area is the point of ... Light continues through the vitreous humor and the light converges on the retina, specifically the fovea centralis of the ... Around the fovea is an area containing yellow pigment termed the macula lutea. ...
Fovea Centralis / embryology Actions. * Search in PubMed * Search in MeSH * Add to Search ... Figure 3. Horizontal and amacrine cell development in the human fetal fovea A. D59-D110 foveas were immunolabeled with PAX6 ( ... Foveas older than D67 were generally defined as a zone free of S-Opsin and NR2E3 immunoreactivity. B. Retinal structure and ... This range of expression was observed in a single section of a D110 retina, from the fovea to the peripheral edge. D. Log2 ...
Fovea Centralis A09.371.729.690 Optic Disk A09.371.729.831 Retinal Neurons A09.371.729.831.500 Amacrine Cells A09.371.729.831. ...
The central region of the macula, termed the fovea centralis, is only about 150 micrometers in diameter and provides detailed ... Consequently, damage to the fovea, even though the structure comprises only 3 to 4 percent of the retinal area, can result in ...
In the posterior pole, a shallow depression is termed the fovea centralis (see the following image). This area is the point of ... Light continues through the vitreous humor and the light converges on the retina, specifically the fovea centralis of the ... Around the fovea is an area containing yellow pigment termed the macula lutea. ...
The fovea centralis is the area of sharpest visual acuity. The conjunctiva covers the eyeball and lines the upper and lower ...
Fovea Centralis Preferred Term Term UI T016930. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1975). ... Fovea Centralis Preferred Concept UI. M0008792. Scope Note. An area approximately 1.5 millimeters in diameter within the macula ... Fovea Centralis. Tree Number(s). A09.371.729.522.436. Unique ID. D005584. RDF Unique Identifier. ... It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the ...
Fovea Centralis Preferred Term Term UI T016930. Date01/01/1999. LexicalTag NON. ThesaurusID NLM (1975). ... Fovea Centralis Preferred Concept UI. M0008792. Scope Note. An area approximately 1.5 millimeters in diameter within the macula ... Fovea Centralis. Tree Number(s). A09.371.729.522.436. Unique ID. D005584. RDF Unique Identifier. ... It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the ...
Congenital hypoplasia of fovea centralis Current Synonym true false 2694076018 Congenital hypoplasia of fovea Current Synonym ... Congenital hypoplasia of fovea centralis (disorder). Code System Preferred Concept Name. Congenital hypoplasia of fovea ... Congenital hypoplasia of fovea centralis (disorder) {429449002 , SNOMED-CT } Parent/Child (Relationship Type) Foveal hypoplasia ...
Fovea Centralis - Preferred Concept UI. M0008792. Scope note. An area approximately 1.5 millimeters in diameter within the ... It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the ... It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. In its center (foveola) are the ...
... fovea centralis, pupil, aqueous humor, lensc. But he did. In addition to the paper trail left by Electric Car and Duraworks, ...
The line, O A, indicates the optic axis ; .S r, the axis of vision ; r, the position of the fovea centralis. ? QUIZ-COMPENDS ...
It has a shallow depression which is known as fovea centralis.. *No image is formed. ... Its central pit is called the fovea. Fovea has only one cone cell and its the region of most distinct vision. ...
In the posterior pole, a shallow depression is termed the fovea centralis (see the following image). This area is the point of ... Light continues through the vitreous humor and the light converges on the retina, specifically the fovea centralis of the ... Around the fovea is an area containing yellow pigment termed the macula lutea. ...
... in rodents without the fovea centralis in the human retina. This study aimed to develop and explore the application of a novel ... The findings advance the knowledge of the pathogenesis and therapeutics of the fovea-involved visual disturbance in human ... EAU model in tree shrews with a cone-dominated retina resembling the human fovea. Methods: Tree shrews were clinically and ...
Una zona a forma di cono, contenente cellule di Müller, forma la porzione centrale e profonda della fovea centralis e ... coinvolge una trazione antero-posteriore e/o una trazione tangenziale esercitata dalla cortex del vitreo posteriore sulla fovea ...
... fovea centralis) which deviates from our central axis of vision by +/- 1 degree. ...
Fovea Centralis, Fundus Oculi, Humans, Multimodal Imaging, Retinal Pigment Epithelium, Tomography, Optical Coherence, Visual ...
Fovea capitis femoris, 240 capituli radii, 214 centralis retinæ, 815 costalis inferior, 93 superior, 93 dentis, 91 femoralis, ...
Fovea centralis. *Golovin-Sivtsev table, for testing visual acuity. *Hyperacuity (scientific term) ... The smallest cone cells in the fovea have sizes corresponding to 0.4 minarc of the visual field, which also places a lower ... Light travels from the fixation object to the fovea through an imaginary path called the visual axis. The eyes tissues and ... In particular, that size is largest in the foveas center, and decreases with increasing distance from there. ...
Founder Effect Four-Dimensional Computed Tomography Fourier Analysis Fournier Gangrene Fourth Ventricle Fovea Centralis Fowl ...
  • citation needed] Approximately half the nerve fibers in the optic nerve carry information from the fovea, while the remaining half carry information from the rest of the retina. (
  • The size of the fovea is relatively small with regard to the rest of the retina. (
  • A number of mechanisms contribute to this effect, and there is even an anatomical basis for visual attention in the fovea centralis , a pit region in the center of the retina with an increased density of photosensitive cone cells responsible for facilitating detailed visual tasks. (
  • The central point for image focus (the visual axis) in the human retina is the fovea. (
  • Some vertebrate retinas have instead of a fovea, another specialization of the central retina, known as an area centralis or a visual streak. (
  • These muscles, named extraocular muscles rotate the eyeball in the orbits and allow the image to be focussed at all times on the fovea of central retina. (
  • Light continues through the vitreous humor and the light converges on the retina, specifically the fovea centralis of the macula. (
  • That is, the subject creates for his own use, a not anatomical but physiological fovea, and each point of the retina changes from how it was previously" (mn. (
  • A new fovea centralis is formed on the intact half of the retina. (
  • A circular field of approximately 6 mm around the fovea is considered the central retina while beyond this is peripheral retina stretching to the ora serrata, 21 mm from the center of the retina (fovea). (
  • Central retina close to the fovea is considerably thicker than peripheral retina (compare Figs. 9 and 10). (
  • The fovea centralis is a thinned-out portion of the retina where only the cones are densely packed. (
  • Anatomical macula / macula lutea / area centralis (clinical: posterior pole): Diameter = 5.5mm (~3.5 disc-diameters) (about 18 deg of VF) Demarcated by the superior and inferior temporal arterial arcades. (
  • GCL has >5 layers of cells, and highest density of cones Anatomical fovea / fovea centralis (clinical: macula) Area of depression in the centre of the macula lutea. (
  • At the posterior pole of the eye lateral to the blind spot, there is a yellowish pigmented spot called macula lutea with a central pit called the fovea centralis. (
  • The fovea is responsible for sharp central vision (also called foveal vision), which is necessary in humans for activities for which visual detail is of primary importance, such as reading and driving. (
  • The fovea is a depression in the inner retinal surface, about 1.5 mm wide, the photoreceptor layer of which is entirely cones and which is specialized for maximum visual acuity. (
  • The high spatial density of cones along with the absence of blood vessels at the fovea accounts for the high visual acuity capability at the fovea. (
  • The fovea centralis is the area of sharpest visual acuity. (
  • Part of the visual field corresponding to the fovea centralis. (
  • This is due, according to Canguilhem, to a veritable reorganization of the damaged visual field: the hemianopic patient's eye develops a new "functional fovea" (mn. (
  • Thus, the area in which [the new fovea centralis ] is located benefits from a higher visual acuity than before. (
  • The fovea centralis is a small, central pit composed of closely packed cones in the eye. (
  • The perifovea contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most central fovea. (
  • The parafovea extends to a radius of 1.25 mm from the central fovea, and the perifovea is found at a 2.75 mm radius from the fovea centralis. (
  • The center of the fovea is the foveola - about 0.35 mm in diameter - or central pit where only cone photoreceptors are present and there are virtually no rods. (
  • The central fovea consists of very compact cones, thinner and more rod-like in appearance than cones elsewhere. (
  • Cones in the central fovea express opsins that are sensitive to green and red light. (
  • Canguilhem stressed that, in the case of hemianopic patients, macular vision, that is, precise and distinct vision usually due to the action of a tiny part of the eye called fovea , tends to remain approximately intact despite the total blurring of the central part of a visus . (
  • Within the fovea is a region of 0.5mm diameter called the foveal avascular zone (an area without any blood vessels). (
  • Therefore, the acuity of foveal vision is limited only by the density of the cone mosaic, and the fovea is the area of the eye with the highest sensitivity to fine details. (
  • In 1795 Sömmering made it clear that the perceptual role of vision is mainly due to this eyeball micro-area, fovea, in which a "reciprocal correspondence of the cells it contains and the nerve fibers can be observed", entailing "the fineness of the sensory and cerebral analysis of light impressions at this point" (mn. (
  • This anatomy is responsible for the depression in the center of the fovea. (
  • The fovea is surrounded by the parafovea belt and the perifovea outer region. (
  • The ellipsoid zone (EZ) in the macular region was disrupted in eight eyes (80%) of which seven were fovea sparing. (
  • As a result of this reorganization, the patient has the impression of looking straight ahead, accommodating [the gaze] no longer from the fovea centralis , but from a point more or less close to it. (
  • In short, by quoting the French philosopher Maurice Pradines, one could say that "we can benefit from optimal vision through the macula, and also through a specific point, the fovea centralis . (
  • The center of the fovea is the foveola - about 0.35 mm in diameter - or central pit where only cone photoreceptors are present and there are virtually no rods. (
  • Starting at the outskirts of the fovea, however, rods gradually appear, and the absolute density of cone receptors progressively decreases. (
  • It includes the sloping walls of the fovea (clivus) and contains a few rods in its periphery. (
  • The fovea centralis is a small, central pit composed of closely packed cones in the eye. (
  • The perifovea contains an even more diminished density of cones, having 12 per 100 micrometres versus 50 per 100 micrometres in the most central fovea. (
  • The fovea is a depression in the inner retinal surface, about 1.5 mm wide, the photoreceptor layer of which is entirely cones and which is specialized for maximum visual acuity. (
  • The high spatial density of cones along with the absence of blood vessels at the fovea accounts for the high visual acuity capability at the fovea. (
  • The central fovea consists of very compact cones, thinner and more rod-like in appearance than cones elsewhere. (
  • Cones in the central fovea express opsins that are sensitive to green and red light. (
  • The fovea is located in a small avascular zone and receives most of its oxygen from the vessels in the choroid, which is across the retinal pigment epithelium and Bruch's membrane. (