Glossary - Eye Care



| A | | B | | C | | D | | E | | F | | G | | H | | I | | J | | K | | L | | M | | N | | O | | P | | Q | | R | | S | | T | | U | | V | | W | | X | | Y | | Z |

A

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accommodation - the ability of the eye to focus.

amblyopia - sometimes called "lazy eye," is the reduction or dimming of vision in an eye that appears to be normal.

Amsler grid - a chart featuring horizontal and vertical lines used to test vision.

anterior chamber - the front section of the eye's interior where aqueous humor flows in and out of providing nourishment to the eye and surrounding tissues.

astigmatism - a vision problem that results in blurred images.

B

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binocular vision - the ability to use both eyes at once.

C

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cataract - a change in the structure of the crystalline lens that causes blurred vision.

choroid - the thin, blood-rich membrane that covers the white of the eyeball; responsible for supplying blood to the retina.

ciliary body - the part of the eye that produces aqueous humor.

conjunctiva - the membrane that lines the exposed eyeball and the inside of the eyelid.

conjunctivitis - inflammation of the conjunctiva of the eye.

cornea - the clear, dome-shaped surface that covers the front of the eye.

corneal curvature - the shape of the front surface of the eye.

D

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depth perception - the ability to distinguish objects in a visual field.

diplopia - double vision.

E

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F

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G

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glaucoma - increased intraocular pressure that can result in optic nerve damage and loss of sight.

H

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hyaloid canal - narrow passageway that allows blood to flow through the eye.

hyperopia - farsightedness.

I

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iris - the colored part of the eye. The iris is partly responsible for regulating the amount of light permitted to enter the eye.

J

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K

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keratitis - inflammation of the cornea.

L

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lens (also called crystalline lens) - the transparent structure inside the eye that focuses light rays onto the retina.

M

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macula - the portion of the eye that allows us to see fine details clearly.

macular degeneration - degeneration in the macular region of the retina that results in decreased central vision and sometimes, in blindness.

miosis - constriction of the pupil.

mydriasis - dilation of the pupil.

myopia - nearsightedness.

N

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near point of accommodation - the closest point in front of the eyes that an object may be clearly focused.

near point of convergence - the maximum extent the two eyes can be turned inward.

O

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ocular hypertension - high (greater than 21 mm Hg) intraocular pressure.

ophthalmoscopy - examination of the internal structure of the eye.

orthokeratology - the use of contact lenses to change the shape of the cornea in order to correct refractive error.

optic nerve - a bundle of more than one million nerve fibers that connects the retina with the brain. The optic nerve is responsible for interpreting the impulses it receives into images.

P

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photophobia - sensitivity to light.

photorefractive keratectomy (PRK) - surgical procedure using an excimer laser to change the shape of the cornea.

pinguecula - irritation caused by the degeneration of the conjunctiva.

posterior chamber - the back section of the eye's interior.

posterior optical segment - portion of the eye located behind the crystalline lens, and including the vitreous, choroid, retina, and optic nerve.

posterior vitreous detachment (PVD) - the separation of the vitreous from the retina.

presbyopia - a form of farsightedness in which it is difficult to focus on close objects or to read.

pupil - the dark center in the middle of the iris through which light passes to the back of the eye.

pupillary response - the constriction or dilation of the pupil as stimulated by light.

Q

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R

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radial keratotomy - a surgical procedure in which incisions are made into the epithelium of the cornea to correct refractive error.

refractive error - the degree to which light reaches the back of the eye - myopia, hyperopia, astigmatism.

retina - the light-sensitive nerve layer that lines the back of the eye. The retina senses light and creates impulses that are sent through the optic nerve to the brain.

retinal detachment - separation of the retina from the epithelium layer and from its blood supply.

S

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sclera - the white visible portion of the eyeball. The muscles that move the eyeball are attached to the sclera.

scotoma - an area of partial or complete loss of vision surrounded by an area of normal vision.

stereopsis - ability to perceive three-dimensional depth.

suspensory ligament of lens - a series of fibers that connect the ciliary body of the eye with the lens, holding it in place.

T

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tonometry - test to measure intraocular pressure for glaucoma.

U

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V

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visual acuity - the space visible to an eye in a given position of gaze.

vitreous body - a clear, jelly-like substance that fills the center of the eye.

W

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X

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Y

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Z

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