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Topic: Optic fovea


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Eye

  
  Fovea - Wikipedia, the free encyclopedia
The fovea, a part of the eye, is a spot located in the center of the macula.
The fovea is responsible for sharp central vision, which is necessary in humans for reading, watching television or movies, driving, and any activity where visual detail is of primary importance.
At the center of the fovea there is a pit with a diameter of about 0.2 mm.
en.wikipedia.org /wiki/Optic_fovea   (340 words)

  
 Optic disc - Wikipedia, the free encyclopedia
The optic disc or optic nerve head is the point in the eye where the optic nerve fibres leave the retina.
Due to absence of light sensitive rods and cones of the retina at this point, it is not sensitive to light and thus is also known as "the blind spot" or "anatomical blind spot".
Women in advanced stage of pregnancy with pre-eclampsia should be screened by an ophthalmoscopic examination of the optic disc for early evidence of rise in intracranial pressure.
en.wikipedia.org /wiki/Optic_disc   (537 words)

  
 [No title]
As the neural folds fuse, the optic sulci evaginate to form the optic vesicles; this evagination is induced by the mesenchyme adjacent to the brain.
The iris is formed from both layers of the optic cup and is continuous with the double-layered epithelium of the ciliary body and with the neural layer of the retina.
The epithelium of the ciliary body consists of a pigmented portion derived from the outer layer of the optic cup (continuous with the pigmented epithelium of the retina) and a nonpigmented portion which represents the anterior prolongation of the neural layer of the retina.
www.kumc.edu /research/medicine/pharmacology/CAI/webCAI/anatomy/em18.wbc   (1597 words)

  
 Retina - Biocrawler   (Site not responding. Last check: 2007-10-31)
At its center is the fovea, a pit that is most sensitive to light and is responsible for our sharp central vision.
The optic nerve carries the ganglion cell axons to the brain and the blood vessels that open into the retina.
The axons from the nasal half cross the brain at the optic chiasma to join with axons from the temporal half of the other eye before passing into the lateral geniculate body.
www.biocrawler.com /encyclopedia/Retina   (1953 words)

  
 Optic fovea Anatomy
The fovea is responsible for sharp central vision, which is necessary in humans for reading, watching televisionor movies, driving, and any activity where visual detail is of primary importance.
Compared to the rest of the retina, the cones in the foveal pit are smaller and more densely packed (in a hexagonalpattern), and they are not obscured by a layer of nerve cells or blood vessels; all of this together accounts for the sharp vision associated with them.
The fovea is largely responsible for the color visionin humanswhich is superior to most other mammals.
www.lumrix.com /medical/anatomy/optic_fovea.html   (327 words)

  
 Genetic Algorithm Based Detection of Optic Disk in Retinal Images
The location of the optic disc is of critical importance in retinal image analysis and is required as a prerequisite stage of exudates detection, blood vessel tracking and segmentation.
The optic disc is the entrance region of blood vessels and optic nerves to the retina and often serves as references of other features.
As the diameter of optic disc is in the range of 65~100 pixels [3] in the retinal image of 512 x 512 pixels, the initial contours are generated within this limit from the optic disc center.
www.acadjournal.com /2006/V17/part6/p5   (1672 words)

  
 Word Definitions
Fovea - The fovea is an indentation in the center of the macula.
Optic Disk - The spot on the retina where the optic nerve leaves the eye.
Optic Nerve - This is the cable connecting the eye to the brain.
geocities.com /coloboma_group/words.html   (1421 words)

  
 Automated localisation of the optic disc, fovea, and retinal blood vessels from digital colour fundus images -- ...
In this study the optic disc, blood vessels, and fovea were accurately detected.
The optic disc appeared in the fundus image as a yellowish region.
The variance image of Figure 2 is shown in Figure 3 and the location of the optic disc in Figure 7.
bjo.bmjjournals.com /cgi/content/full/83/8/902   (4077 words)

  
 [No title]
This electrical energy, in the form of a nerve impulse, travels from the eye's sensory neurons along the optic nerve (cranial nerve III) to the occipital lobe of the cortex where it is interpreted as a visual image.
It is a darker area in which blood vessels are absent and the fovea appears to be a slightly lighter area in its center.
The crossover of the optic nerve fibers at the optic chiasma is total.
www.zoology.ubc.ca /~lacombe/biomania/biol153/labfinal/sightL.doc   (3445 words)

  
 Lab exercises- Retina, choroid, and sclera
An overview of the optic nerve seen as it leaves the eye is shown in the following photographs.
In the center of the fovea is the area of most distinct vision.
Compare the vascularization of the retina in the main region (where the optic nerve is running) with that in the fovea.
cellbio.utmb.edu /microanatomy/eye/Retina_lab.htm   (745 words)

  
 Eye and Retina
The fovea defines the center of the retina, and is the region of highest visual acuity.
The fovea is directed towards whatever object you wish to study most closely - this sentence, at the moment.
In the fovea there are almost exclusively cones, and they are at their highest density.
thalamus.wustl.edu /course/eyeret.html   (1414 words)

  
 Eye - The real meaning from Timesharetalk wikipedia   (Site not responding. Last check: 2007-10-31)
Such eyes are typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often an iris which regulates the intensity of the light that enters the eye.
The fovea is a dip in the retina directly opposite the lens, which is densely packed with cone cells.
The optic disc, sometimes referred to as the anatomical blind spot, is a point on the retina where the optic nerve pierces the retina to connect to the nerve cells on its inside.
www.timesharetalk.co.uk /wiki.asp?k=Eye   (4824 words)

  
 Eye Anatomy - one our most important sensory organs   (Site not responding. Last check: 2007-10-31)
The optic nerve and the central retinal blood vessels enter the back of the eye at the disc (also called the blind spot).
The fovea (1.5 mm) is just behind the macula where the highest concentration of cone photoreceptors are concentrated.
The sclera is the tough outer wall of the eye and the choroid is the thin spongy layer between it and the retina filled with blood vessels.
www.brianseye.com /anatomy.htm   (172 words)

  
 Handbook of Ocular Disease Management - Presumed Ocular Histoplasmosis Syndrome
Atrophy or scarring adjacent to the optic disc, which appears as a flat, whitish-brown lesion; the presentation varies depending on the amount of retinal pigmentary epithelial hyperplasia next to the optic disc.
Optic disc edema is an occasional finding in active disease.
Presumed ocular histoplamosis syndrome is a dimorphic fungal disease endemic to river valley climates.
www.revoptom.com /handbook/sect5o.htm   (660 words)

  
 Human Physiology, Stark, Vision
Here is a picture showing focus of an arrow up-side-down on the retina, trivial except that is shows that most of the bending is at the cornea where the change of index of refraction at the air-cornea interface is very large.
Optic disc is where optic nerve exits and blood supply enters and exits.
Currently, it is known that the carotenoids lutein and zeaxanthin are in nerve layers in the light path to the receptors of the fovea (cones).
starklab.slu.edu /Physio/Vision.htm   (1520 words)

  
 Eye
Compound eyes are found among the arthropods (insects and kin), and are composed of many simple facets which give a pixelated image (not multiple images as is often believed).
In most vertebrates and some mollusks (such as octopuses) the eye works by projecting images onto a light-sensitive retina, where the light is detected and transmitted to the brain via the optic nerve.
The eye is typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing lens and often a muscle called the iris that controls how much light enters.
www.askfactmaster.com /Eye   (425 words)

  
 O'Brien, Mol Vis 2003; 9:401-409.
In the human retina, the anatomical and visual axis is centered on the fovea, which is characterized as a pit is located on the center of gaze that is overlain with the highest density of cone photoreceptors.
However, in the central 100 μm of the fovea, S cones are absent [2,3] and rods are absent from the central 300 μm [1].
Near the optic disc (Figure 7B), the ONL was composed of a single layer of cones overlying multiple layers of rods, which was a major change from Fwk 15 (Figure 5).
www.molvis.org /molvis/v9/a52   (4332 words)

  
 Comparing the Optics of the Microscope with that of an Eye
The fovea is where the image is focused the sharpest.
Have the students label the retina, fovea, optic nerve, cornea, lens, and iris after you discuss what each of them.
The optic nerve transmits the information to the retina; and the brain inverts the inverted image, so we see the image the way it actually is.
www.msnucleus.org /membership/html/k-6/as/technology/5/ast5_6a.html   (341 words)

  
 Extraocular Muscle Insertions Relative to the Fovea and Optic Nerve: Humans and Rhesus Macaque -- Feng et al. 46 (10): ...
Extraocular Muscle Insertions Relative to the Fovea and Optic Nerve: Humans and Rhesus Macaque -- Feng et al.
insertions relative to the fovea and the optic nerve.
SD) from the temporal border of the optic nerve (ON) to the
www.iovs.org /cgi/content/abstract/46/10/3493   (310 words)

  
 Arch Ophthalmol -- Abstract: Optic Disc, Foveal, and Extrafoveal Damage Due to Surgical Separation of the Vitreous, ...
Arch Ophthalmol -- Abstract: Optic Disc, Foveal, and Extrafoveal Damage Due to Surgical Separation of the Vitreous, November 2001, Russell and Hageman 119 (11): 1653
Optic Disc, Foveal, and Extrafoveal Damage Due to Surgical Separation of the Vitreous
Avulsion of axon bundles in the optic disc was noted
archopht.ama-assn.org /cgi/content/abstract/119/11/1653   (307 words)

  
 Automatic detection of the optic disc, fovea and vacular arch in digital color photographs of the retina
We present a novel method that determines whether a macula centered retinal image is from the left or right eye and automatically detects the optic disc, the fovea and the vascular arch by inferring the location of a set of landmarks placed on these structures.
The best performing system localizes the OD in 91\% of all cases, the fovea in 94\% of all cases and correctly positions 74\% of all vessel landmarks.
The results show that a combination of global and local energy function components is required to obtain optimal results.
www.bmva.ac.uk /bmvc/2005/papers/paper-57-61.html   (251 words)

  
 Identifying photoreceptors in blind eyes caused by RPE65 mutations: Prerequisite for human gene therapy success -- ...
fovea and optic nerve to determine local statistics.
At 3.6 mm temporal to the fovea, rod photoreceptor density
ONL at the fovea reflects the peak spatial density of cones,
www.pnas.org /cgi/content/full/102/17/6177   (4996 words)

  
 View Study [NEI Clinical Studies]
Treatment was performed under topical anesthesia using the argon laser to achieve a grid pattern over the area of capillary leakage identified by fluorescein in the macular region.
Photocoagulation was extended no closer to the fovea than the edge of the foveal avascular zone and did not extend peripherally beyond the major vascular arcade.
The efficacy of treatment was judged on the basis of visual acuity measurements as well as assessment of the subsequent development of neovascularization and/or vitreous hemorrhage.
www.nei.nih.gov /neitrials/viewStudyWeb.aspx?id=64   (582 words)

  
 Fovea - Fovea Design   (Site not responding. Last check: 2007-10-31)
Fovea refers to the center of the retina that can produce the sharpest eyesight and contains the most cones.
Medical dictionary definition of Fovea centralis as a medical term including diseases, symptoms, treatments, and other medical and health issues.
Fovea Video is a full-service video production company in the South Bay.
finderpad.com /?q=fovea   (426 words)

  
 Astrocytes and Blood Vessels Define the Foveal Rim during Primate Retinal Development -- Provis et al. 41 (10): 2827 -- ...
(D, E) At Fd115 in the region (D) between the fovea and optic disc and (E) near the fovea, branches of the GCP passed through the IPL and were beginning to form the ICP (small arrows) and in (D) a few capillaries were present in the OCP (arrowheads).
or approximately halfway to the incipient fovea (Figs.
Hendrickson, A, Kupfer, C (1976) The histogenesis of the fovea in the macaque monkey Invest Ophthalmol.
www.iovs.org /cgi/content/full/41/10/2827   (6087 words)

  
 [No title]
To allow light to reach the photoreceptors without being absorbed or greatly scattered (which would distort the visual image), the axons of neurons in proximal layers of the retina are unmyelinated so that these layers of cells are relatively transparent.
In the fovea, the cell bodies of the proximal retinal neurons are shifted to the side, enabling the photoreceptors there to receive the visual image in its least distorted form (Fig.
-(hence the constant eye movements when humans examine visual scenes of interest — projecting to fovea optic disc: where the optic nerve fibers leave the retina = blind spot.
cogsci.ucsd.edu /~ffilimon/COGS107B/107BSection4.doc   (354 words)

  
 Arch Ophthalmol -- Abstract: Initial Stages of Posterior Vitreous Detachment in Healthy Eyes of Older Persons Evaluated ...
PVD in all quadrants, with residual attachment to the fovea
the posterior pole, with residual attachment to the optic disc
with persistent attachment to the fovea and optic nerve head, with
archopht.ama-assn.org /cgi/content/abstract/119/10/1475   (366 words)

  
 Eye - Gurupedia   (Site not responding. Last check: 2007-10-31)
retina, where the light is detected and transmitted to the brain via the optic nerve.
The eye is typically roughly spherical, filled with a transparent gel-like substance called the vitreous humour, with a focusing
Optic chiasm - Lateral geniculate nucleus - Visual cortex
www.gurupedia.com /e/ey/eye.htm   (319 words)

  
 histolab3b.htm
The Fovea and Optic Nerve may not be visible on your particular slide - borrow one that has them or look at a demonstration.
Where the nerve fibers from the retina converge to form the optic disk (or papilla), the sclera has perforations (Lamina Cribrosa).
The fovea centralis is present on very few slides.
faculty.une.edu /com/abell/histo/histolab3b.htm   (2255 words)

  
 Retinal imaging and diagnostics - Talia Technology - The Eye   (Site not responding. Last check: 2007-10-31)
The retina, at the back of the eye, acts like the film in a camera.
Light is changed by the retina into electric impulses that are carried by the optic nerve to the brain.
For a person to see clearly, light must be focused precisely on the retina.
www.talia.com /talia/site/frames.asp?Dir=medical_education&Main=the_eye   (100 words)

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