Age-related Macular Degeneration |
Corneal Diseases |
Cataracts |
Glaucoma |
Diabetic Retinopathy |
NEP
a consequence of ciliary muscle contraction in which near objects
are in focus and distant objects are out of focus; changes in
lens shape that help the eye focus on closer objects
Results from deterioration of the macula, which is the back
portion of the retina responsible for clear, sharp vision. For
more information, click on Age-related Macular
Degeneration
the space
between the cornea and the iris that is filled with aqueous
humor
the clear fluid
contained in the anterior chamber of the eye; supplies nutrients
and oxygen to and carries metabolic waste and carbon dioxide
away from the lens and the cornea; continually being formed
by the ciliary body and drained out of the eye through the trabecular
meshwork and canal of Schlemm; balanced formation and drainage
of aqueous maintains intraocular pressure
a condition that
occurs when the front surface of the eye, the cornea, is slightly
irregular in shape. This irregular shape prevents light from
focusing properly on the back of the eye (the retina). As a
result, vision may be blurred at all distances.
(1) A small area
of the retina where the optic nerve enters the eye; occurs normally
in all eyes. (2) Any gap in the visual field corresponding to
an area of the retina where no visual cells are present.
: a clouding of part
or all of the lens inside the eye, resulting in blurred or distorted
vision.
see Visual
Acuity
the posterior portion
of the uveal tract; a vascular layer that separates the fibrous
layer from the sensory layer and provides all eye layers with
90% of their blood supply
the delicate mucous
membrane that lines the inside of the eyelid and folds over
to cover part of the sclera; provides a barrier against outside
infection; secretes mucin; helps spread and drain the tear film;
helps carry waste products away from the eye
The ability
to perceive differences between an object and its background.
The transparent tissue
that covers the front of the eye.
Also called hyperopia. Condition in which the length of the
eye is too short, causing light rays to focus behind the retina
rather than on it, resulting in blurred near vision. Additional
symptoms include eyestrain and squinting.
The interior lining
of the eyeball, including the retina, optic disc, and macula.
This portion of the inner eye can be seen during an eye examination
by looking through the pupil.
an eye disease in
which the passages that allow fluid in the eye to drain become
clogged or blocked, or there is too much fluid produced inside
of the eye. Increased pressure inside the eye then damages the
optic nerve and causes vision loss.
the pressure exerted on the eye by the fluids contained within
the eye
the colored ring of tissue
suspended behind the cornea and immediately in front of the
lens. It regulates the amount of light entering the eye by adjusting
the size of the pupil.
a relatively
large gland, located in the upper lateral portion of the orbit;
when triggered by irritation or emotional stimuli, produces
copious aqueous tears
a transparent, flexible
structure located behind the iris; changes shape to allow light
to focus on the sensory components of the eye; the second major
refracting surface (after the cornea) that light passes through
on the way to the retina
a person is considered LEGALLY blind when the best corrected
visual acuity is 20/200, or the person's visual field is 20
degrees or less. It is not true that all blind persons have
absolutely no sight; in fact, most blind persons have some remaining
vision. A person may be considered blind when he/she can no
longer drive safely, has difficulty reading a newspaper, or
cannot see objects to the side.
The small, sensitive
area of the central retina. It provides vision for fine work
and reading.
the
inability to see clearly at a distance. It is caused by an eyeball
that is too long or whose outside surface (the cornea) is too
curved. Nearsightedness can be inherited or caused by the stress
of concentrating for long periods on work at a close distance.
an examination
of the retina in which the eye doctor, (1) looks through a device
with a special magnifying lens that provides a narrow view of
the retina, or (2) looks through a special magnifying glass
and gains a wide view of the retina.
the nerve that
connects the eye to the brain; carries electrical impulses from
the retina (specifically, the ganglion cells) to the brain
Side vision.
The ability to see objects and movement outside of the direct
line of vision.
The space
between the back of the iris and the front face of the vitreous.
It is filled with aqueous fluid.
the gradual loss
of the eye's ability to change focus for seeing near objects.
It happens because, with age, the lens inside the eye gradually
loses its flexibility and focusing ability. It occurs in almost
all people over age 45.
the adjustable opening
at the center of the iris that allows varying amounts of light
to enter the eye.
The sensory membrane
that lines the eye; it receives images formed by the lens and
converts them into signals that reach the brain by way of the
optic nerve.
the pigment cell layer that nourishes the retinal cells. It
is located just outside the retina and attached to the choroid.
the tough, white, outer
layer (coat) of the eyeball. Along with the cornea, it protects
the entire eyeball.
a standard test
that determines the fluid pressure inside the eye. Elevated
pressure is a possible sign of glaucoma
the ability
to distinguish details and shapes of objects. It is also called
central vision.
an eye
chart test that measures how well you see at various distances.
The entire area
that can be seen when the eye is looking straight ahead, including
peripheral side vision.
The transparent,
colorless mass of gel that lies behind the lens and in front
of retina.
Excerpted from:
Dictionary of EyeTerminology and http://www.careforyoureyes.com/cat172.html
