| ACCOMMODATION |
The ability of the eye
to change its focus from distant to near objects; this occurs when the lens inside the eye
changes its shape. |
| ACCOMMODATIVE INSUFFICIENCY |
Loss of, or less than
the age appropropriate amount of accommodation. |
| ADNEXA |
The accessory
structures of the eye, including the eyelids, lacrimal gland, lacrimal ducts etc. |
| AQUEOUS HUMOR, AQUEOUS FLUID |
Clear, watery fluid
that fills the front of the eye. |
- ALK
-
|
Automated lamellar
keratoplasty (removal of a part of the central corneal stroma) to effect a change on the
refractive error. |
- AMAUROSIS
|
Partial or total
blindness. |
- AMETROPIA
|
Refractive condition
in which parallel rays do not focus on the retina; manifestation of
refracive error. |
- AMBLYOPIA
-
|
Often called
"lazy eye" it is a condition in which the best corrected vision in one eye is
poorer than 20/20 (6/6) in the absence of any obvious structural anomalies or ocular
disease. |
| AMSLER GRID |
A hand held chart
featuring equally spaced horizontal and vertical lines, usually white on black background,
used to detect central visual field defects. |
- ANISOMETROPIA
|
A condition of unequal
refracive state for the two eyes. |
- ANTERIOR SEGMENT
-
|
The part of the eye
anterior to the crystalline lens, including the cornea, anterior chamber, iris and ciliary
body. |
- ANTIOXIDANTS
-
-
|
Micronutrients which
destroy or neutralize free radicals, molecules which have been implicated as one causative
factor in the stimulation of abnormal cellular reproduction (cancer) and cellular
destruction (aging). |
| APHAKIA |
The absence of the
eye's natural crystalline lens, usually after cataract removal. |
| APHAKIC SPECTACLES |
Thick, plus-powered
eyeglasses that were once the standard optical correction following extraction of
cataract. The glasses were cumbersome and greatly distorted peripheral vision. Today, an
intraocular lens (IOL) is implanted in the eye after the cataract is removed to replace
the focusing power of the natural lens eliminating the need for aphakic spectacles. |
| ARMD: AGE RELATED MACULAR DEGENERATION |
Degeneration of the
photoreceptors in the macular (central) region of the retina resulting in decreased
central vision. |
| ASTHENOPIA |
Subjective symptoms or
distress arising from the use of the eyes; as in eyestrain. |
| ASTIGMATISM |
A condition in which
the surface of the cornea is not spherical; creates blurriness or "distortion"
at all distances because light is not focused symmetrically on the retina. |
- ASTIGMATIC KERATOTOMY (AK)
|
An incisional
refractive surgical technique in which transverse incisions are made in the cornea to
reduce or eliminate astigmatism. |
- BINOCULAR VISION
-
|
The simultaneous use
of the two eyes. Normal binocular vision yields a stereoscopic image and depth perception. |
| BLIND SPOT |
(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 a area of the retina where no visual
cells are present; associated with eye disease. |
- CATARACT
-
|
An opacity or loss of
transparency of the crystalline lens which results in loss of light transmission, image
degradation and reduced vision. |
| CENTRAL VISION |
The area of vision
used for fine detail straight ahead; perfect vision measures 20/20. |
| CILIARY MUSCLES |
The muscles that
enable the lens to change shape for focusing. |
- COLOR VISION
-
|
The ability to
perceive differences in color, including hue, saturation and brightness. |
| CONES |
One of two types of
light receptor cells in the retina. Cones see fine detail and color best. |
| CONJUNCTIVA |
The mucous membrane
lining the inner surfaces of the eyelids and the outer surface of the white of the eye. |
- CONJUNCTIVITIS
-
|
Inflammation of the
conjunctiva. May be caused by bacteria, virus, allergens or chemicals. |
- CONVERGENCE/DIVERGENCE
-
|
The turning of the
eyes simultaneously inwards/outwards so that they are both "aimed" towards the
object being viewed. |
| CORNEA |
The clear, strong
surface layer of the eye covering the iris and pupil. |
- CRYSTALLINE LENS
-
|
The natural lens of
the eye, located behind the pupil, which helps bring rays of light to focus on the retina.
The original state of the lens is transparent, but the lens becomes cloudy with
age. (see
cataract). |
- DEPTH PERCEPTION
-
|
The ability of the
vision system to perceive the relative positions of objects in the visual field. |
| DILATION |
Enlarging the pupil,
usually with eye drops |
- DIOPTER (DY-AHP-TUR)
-
|
A unit measurement of
the degree to which light converges or diverges; Diopters are used to define of lens's
refractive power. Equal to the reciprocal of the focal length of a lens (in meters), e.g.,
a 2-diopter lens brings parallel rays of light to a focus at half a meter. |
- DIPLOPIA
-
|
A condition in which a
single object is perceived as two; also called double vision. |
- EMMETROPIA
-
|
Refractive condition
in which no refractive error is present and distant images are focused sharply on the
retina with no need for corrective lenses. |
- ESOPHORIA
-
-
|
The position of the
eyes in an over-converged position compensated by the external eye muscles so that the
eyes do not appear turned inward. |
- ESOTROPIA
-
|
The position of the
eyes in an over-converged position so that non-fixating eye is turned inward. |
- EXOPHORIA
-
|
The position of the
eyes in an over-diverged position compensated by the external eye muscles so that the eyes
do not appear turned outward. |
- EXTRA-OCULAR/EXTERNAL OCULAR MUSCLES
|
The six muscles that
turn the eyes to position them appropriately for viewing objects in various fields of
view. |
- EXTRACAPSULAR CATARACT EXTRACTION
|
A surgical procedure
which removes the cataractous lens but leaves the rear lens capsule in place. |
- FUNCTIONAL VISUAL DISABILITY
-
|
The degree to which a
visual error interferes with a person's ability to perform normal daily activities, such
as reading, driving at night, or performing hobbies. |
| FUNDUS |
The interior of the
eye, seen best after dilation. |
- GLAUCOMA
-
|
Characteristic optic
nerve damage often associated with abnormally increased intraocular pressure and loss of
visual field. |
| HEMIANOPSIA |
Loss of one half of
the visual field in one or both eyes. |
| HYPEROPIA |
Farsightedness;
(usually seeing at distance better than at near) |
- HYPOXIA
|
A deficiency of oxygen
supply to a tissue |
- INTRAOCULAR LENS
-
|
A plastic lens that is
surgically implanted to replace the focusing power of the natural lens of the eye
following cataract extraction. There are numerous styles of IOLs, including foldable IOLs
and multifocal IOLs. |
| INTRAOCULAR PRESSURE
(IOP) |
The fluid pressure
inside the eye. |
| IRIS |
The colored part of
the eye surrounding the pupil. |
| KERATITIS |
Inflammation of the
cornea. |
| LENS |
The eye's natural
internal focusing structure. |
| LEGAL BLINDNESS |
In the U.S.,
visual acuity of 20/200 or worse in the better eye with corrective lenses. |
| MACULA |
The central area of
the retina where most of the cones are located - provides fine detail vision. |
- MACULAR EDEMA
|
A collection of fluid
in and under the macular portion of the retina. |
| MIOSIS |
Pupillary constriction |
| MYDRIASIS |
Pupillary dilation. |
| MYOPIA |
Nearsightedness;
(usually seeing at near better than at distance.) |
- NEOVASCULARIZATION
-
|
The formation of new
blood vessels, often fragile and inappropriate for the location. |
| NYSTAGMUS |
A rapid,
repetitive,
involuntary movement or rotation of the eyes. |
- OPHTHALMOLOGIST
-
|
A physician
specializing in medical, and surgical treatment of eye diseases and disorders. |
| OPTIC DISC |
The area where the
optic nerve connects to the retina. |
| OPTIC NERVE |
The nerve that sends
messages from the eye to the brain. |
- OPTIC NEURITIS
-
|
A condition of
inflammation of the optic nerve. |
| OPTOMETRIST |
A
physician who treats refractive errors and eye diseases |
| OPHTHALMOSCOPY |
Examination of the
internal structures of the eye using an illumination and magnification
system. (ophthalmoscope). |
| ORTHOKERATOLOGY |
A non-surgical
procedure using contact lenses to alter the shape of the cornea to effect a change in the
refractive error. |
- PAPILLEDEMA
-
|
Non-inflammatory
swelling/elevation of the optic nerve due to increased intracranial pressure. |
| PERIPHERAL VISION |
Side vision; seeing
objects or movement to the side of the direction of gaze. |
- PHACOEMULSIFICATION
-
|
A form of
extracapsular cataract extraction in which an ultrasonic instrument is used to shatter and
break up a cataract, making it easier to remove. |
| PHOTOPHOBIA |
Sensitivity to light. |
| PHOTOREFRACTIVE KERATOTOMY |
A technique employing
an excimer laser to reshape the surface of the cornea and thereby reducing
nearsightedness. |
| PINGECULA |
A (usually) irritation
caused by degeneration of the conjunctiva resulting in a thickening and yellowing of the
normally thin transparent tissue. |
| POSTERIOR CAPSULAR OPACIFICATION |
Opacification of the
posterior lens capsule following cataract extraction. Sometimes called "after
cataract," and may cause blurred vision. |
| POSTERIOR SEGMENT |
- The part of the eye posterior (behind) to the crystalline
lens, including the vitreous, choroid, retina and optic nerve.
|
| POSTERIOR VITREOUS DETACHMENT |
The separation of the
vitreous body from itıs attachment from the retinal surface due to shrinkage from age,
degenerative or inflammatory conditions or trauma. |
| PRESBYOPIA |
The gradual loss of
the eye's ability to change focus from distance to near; occurs in almost everyone
sometime after age 40. |
| PRISM |
An optical element
which deviates the path of light. |
| PTOSIS |
Drooping of the upper
or lower eyelid from it's normal position. |
| PUPIL |
The black circle in
the center of the iris that opens and closes to allow light into the eye. |
| PUPILLARY RESPONSE |
The constriction and
dilation of the pupil due to stimulation by light or accommodation. |
- RADIAL KERATOTOMY
|
A surgical procedure
using diamond scalpel blades to create linear incisions into the cornea which result in
the flattening of the tissue and thereby altering the refractive error. |
| REFRACTION |
A determination of the
optical error of the eye. |
| REFRACTIVE ERROR |
The degree to which
images received by the eyes are not focused on the retina, e.g.: myopia, hyperopia,
astigmatism. |
RETINA
|
The layer of light
receptor cells at the back of the eye which forms an image that is sent to the brain. |
- RETINAL DETACHMENT
-
|
A separation of the
retina from the back wall of the eye. Results in loss of vision in the detached area.
Repairable with fair to good prognosis for vision in the early stages. |
| RODS, ROD CELLS |
One of two types of
light receptor cells in the retina; rods see in dim light and provide side vision. |
| SCLERA |
The tough, white,
outer layer of the eyeball; with the cornea, it protects the entire eyeball. |
- SCOTOMA
-
|
An area of partial or
complete loss of vision surrounded by an area of normal vision. |
| STEREOPSIS |
The ability to
perceive three dimensional depth. |
| STRABISMUS |
The condition in which
binocular fixation is not present; commonly referred to as "cross eyed." |
| SUPPRESSION |
The inability to
perceive all of part of objects in the field of vision of one eye. |
| TONOMETRY |
A procedure for the
measurement of intraocular pressure. |
| TRABECULAR MESHWORK |
The area where fluid
drains out of the eye. |
| UNLTAVIOLET RADIATION |
Radiant energy with a
wavelength just below that of the visible light. UV-c is the shortest wavelength at
200-280nm and is absorbed by the atmosphere before reaching the surface. Extremely
damaging to living tissue. UV-b, a t 280-315nm is "burning rays" of the sun and
is damaging to most living tissue. UV-a, at 315-400nm are "tanning rays" of the
sun and is somewhat damaging to certain tissues. UV radiation has been described as a
contributing factor to the processes which result in ARMD and cataracts. |
| VISION THERAPY |
(Orthopedics, vision
training, eye exercises) a treatment process for the improvement of visual perception
and/or coordination of the two eyes for efficient and comfortable binocular vision. |
| VISUAL ACUITY |
The ability to see
fine detail - "perfect" visual acuity is 20/20. |
| VISUAL FIELD |
The entire area that
the eye can see from side to side (includes peripheral vision). |
| VITREOUS |
The thick gelatinous
material that fills the back of the eye in front of the retina. |
| YAG LASER |
The YAG laser is an
instrument that emits a short pulsed, high energy light beam that can be precisely focused
to cut, vaporize, or fragment tissue. |
