Eye Conditions

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

ABLEPHARON

absence of the eyelids

ABNORMAL RETINAL CORRESPONDENCE

see "anomalous retinal correspondence"

ACCOMMODATION

the adjustment of the eye for seeing at different distances, accomplished by changing the shape of the crystalline lens through action of the ciliary muscle, thus focusing a clear image on the retina

ACCOMMODATION

process by which the refractive power of the lens is increased through contraction of the ciliary muscle (N III), causing an increased thickness and curvature of the lens

ACCOMMODATIVE ESTROPHIA

inward deviation of the eyes characteristically more marked for near than far and increased by ciliary muscle contraction in accommodation

ACCOMMODATIVE EXTROPHIA

outward deviation of the eyes, usually secondary to uncorrected myopia

ACHROMATOPSIA

color blindness; often applied to complete color blindness

AFTER-IMAGE

visual sensation occurring after the stimulus causing it has ceased

AGNOSIA

inability to recognize objects by sight with ability to recognize by touch; a sign of lesions of the angular gyrus of the parietooccipital fissure

AGRAPHIA

(visual) loss of ability to write

ALBINISM

a hereditary loss of pigment in the iris, skin, and hair; usually associated with lowered visually acuity, nystagmus, and photphobia and often accompanied by refractive errors

ALTERNATING CORSS-EYES - SQUINT OR STRABISMUS

deviation of the eyes in which either eye may be used for fixation while the other deviates

AMAUROSIS

nearly obsolete term indicating loss of vision

AMBLYOPIA

poor vision or loss of visual acuity without any apparent disease of the eye

AMBLOYOPIA EX ANOPSIA

poor vision or loss of visual acuity from inaccurate focusing on retina due to refractive errors, cataract; dimness of vision due to disuse of the eye

AMBLYOPIA

subnormal visual acuity without any apparent disease of the eye

ex anopsia: refractive, functional, or strabismic amblyopia now preferred
functional: there is inhibition as in refractive or strabismic amblyopia
organic: caused by organic disease, such as optic atrophy, macular degeneration, or cataract
refractive: arises from a refractive err, particularly a marked difference in refraction of the two eyes (anisometropia)
relative: associated with organic amblyopia upon which is superimposed an inhibition as in strabismic amblyopia
strabismic: associated with crossing of the eyes that occurs before the establishment of normal visual acuity in each eye; there appears to be active inhibition of perception of the retinal image transmitted by one eye

AMETROPIA

refractive defect which prevents the eye in a state of rest from focusing the image of distant objects upon the retina; includes hyperopia, myopia, and astigmatism

ANGIOID STREAKS

abnormality of the elastic layer of Bruch's membrane giving rise to pigmented striations of the ocular fundus; associated with a variety of systemic diseases such as pseudozanthomas elasticum, sickle cell disease, and osteitis deformance (Paget's disease), and a variety of generalized diseases affecting the elastic lamina of blood vessels

ANGLE-CLOSURE GLAUCOMA

ocular abnormality in which the intraocular pressure increases, often quickly, because the anterior aqueous humor is mechanically prevented from reaching the trabecular meshwork

ANGLE OF ANOMALY

in strabismus, the degree an eye deviates from parallelism

ANIRIDA

congenital absence of the iris

ANISEIKONIA

condition in which the ocular image of an object as seen by one eye differs in size or shape from that seen by the other eye

ANISOCORIA

condition in which the pupil of the two eyes are of unequal size

ANISOMETROPIA

condition in which the refractive errors in the two eyes are different

ANKLYOBLEPHARAON

condition in which the margins of the eyelids are fused together

ANOMALOUS TRICHROMATISM

defect of color vision in which there appears to be a deficiency of one of the cone pigments (see also "deuteranomaly", "protoanomaly", "tritanomaly")

ANIRIDIA

absence of iris, usually incomplete, with iris root present

ANOPHTHALMOS

absence of a true eyeball

ANTERIOR CHAMBER

space in front of the eye, bounded in front by the cornea, behind by the iris, filled with aqueous

APHAKIA

absence of the lens of the eye

AQUEOUS

clear, watery fluid which fills the anterior and posterior chambers within the front part of the eye

AQUEOUS FLARE

tyndall beam observed with a biomicroscope when excessive protein is present in the anterior aqueous humor

AQUEOUS HUMOR

fluid that fills the posterior and anterior chambers

ARCUATE SCOTOMA

area of blindness in the field of vision of characteristic are shape caused by interruption of a nerve fiber bundle in the retina; most often seen in glaucoma

ARGYOSIS

Silver deposits in the conjunctive, corneal epithelium, stroma, and Descemet's membrane after long term use of silver-containing eye drops

ASTEROID HYALOSIS

fixed opacities composed of a calcium lipid complex that occur in an otherwise normal vitreous body; there are no symptoms

ASTHENOPIA

eye fatigue caused by tiring of the internal and external muscles

ASTIGMATISM

refractive error which prevents the light rays from coming to a single focus on the retina because of different degrees of refraction in the various meridians of the eye

ATROPHIC EYEBALL

degenerated sightless eyeball

ATROPHY, OPTIC

degeneration of the optic nerve

AVULSION OF CARUNCLE

term usually applied to a laceration involving inner one-sixth (lacrimal portion) of lower eyelid with rupture of the inferior canaliculus

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B

BAND KERATOPATHY

deposition of calcium edema, often associated with sudden prolonged increase in intraocular pressure or wearing of contact lenses for an excessively long period (Scattler's veil)

BELL'S PALSY

peripheral paralysis of the facial nerve (N VII)

BELL'S PHENOMENA

upward and outward deviation of the eyes occurring with forcible closure of the eyelids or sleep

BERGMEISTER'S PAPILLA

small mass of glial cells that surround the hyaloid artery in the center of the optic disk; on occasion it persists and obliterates the physiologic cup of the optic disk

BI-CONVEX

two surfaces each of which is part of the outer surface of a sphere

BINOCULAR

pertaining to both eyes

BINOCULAR VISION

the ability to use the two eyes simultaneously to focus on the same object and to fuse the two images into a single image, which gives a correct interpretation of its solidity and its position in space, important in depth perception

BIOMICROSCOPE

microscope for examining the eye and consisting essentially of a dissecting microscope combined with a light source that projects a rectangular light beam that can be changed in size and focus

BITEMPORAL

pertaining to both temples, as bitemporal hemianopsia-blindness in the outer or temporal half of each visual field

BITOT'S SPOT

highly retractile mass with silver-gray hue and having a foamy surface that appears on the bulbar conjunctiva in Vitamin A deficiency

BLEPHARITIS

inflammation of the margin of eyelids; occurs in squamos (seborrheic) ulcerative forms

BLEPHAROCHALASIS

relaxation of the skin of the eyelid due to atrophy of the elastic tissue; the upper eyelid is commonly involved and a fold of tissue hangs over the lid margin

BLEPHAROPHIMOSIS

narrowing of the palpebral fissure, often associated with excessive distance between the inner canthi and drooping of the upper eyelid (Blepharoptosis)

BLEPHAROPLASTY

plastic surgery of the eyelids

BLEPHAROPTOSIS

drooping of the upper lid due to paralysis of the oculomotor (N III) nerve or the sympathetic nerves or to excessive weight of the upper lids

BLEPHAROSPASM

tonic spasm of the orbicularis oculi muscle; spasm of the orbicular muscle of the eyelids

BLIND SPOT

the part of the visual field corresponding to that part of the optic fundus where the optic nerve enters is the physiological blind spot. In disease, it corresponds to an area in the retina which does not function. This term applies to normal eye, not to diseased area.

BLINDNESS

inability to see; defined by Internal Revenue Service as reduction of best corrected visual acuity to 20/200 or less in better eye or restriction of the visual field to 20 degrees or less; defined by Social Security Agency as reduction of vision in best corrected eye to 5/200 or less, in industry, reduction of the best corrected visual acuity to less than 20/200; some states include up to 30 degrees

color: see deuteranopia, protanopia, tritanopia, deuteranomaly, protanomaly, tritanomaly
cortical: caused by a lesion in the cortical visual center
night: inefficient dark adaptation so that vision is markedly reduced in reduced illumination
snow: inability to open eyes to see; secondary to ultraviolet keratitis

BLOWOUT FRACTURE OF ORBIT

comminuted fracture of the roof of the maxillary sinus with prolapse of intraorbital contents into the antrum; there is enophthalmos, blepharoptosis, inability to turn the eye upward, and usually infraorbital anesthesia

BLUE SCLERA

abnormality in which the sclera is thin and has blue appearance arising from the underlying pigmented choroids

BRUSHFIELD'S SPOTS

transient whitish areas in the iris at birth that occurs in Down's Syndrome

BULBAR CONJUNCTIVA

the part of the conjunctiva concerning the anterior surface of the eyeball

BUPHTHALMOS

enlargement of the eye usually occurring as a result of congenital glaucoma; large eyeball (infantile glaucoma, ox eye)

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C

CAMPIMETER

alternative term for perimeter, screen used for visual field defects

CANAL OF SCHLEMM

a circular canal situated at the juncture of the sclera and cornea through with the aqueous is excreted after it has circulated between the lens and the iris and between the iris and the cornea

CANALICULITIS

inflammation of the lacrimal canaliculi; often due to fungus infection

CANDELA

unit of luminous intensity; one candela is defined as the luminous intensity of 1/60 of a square centimeter of projected area of a blackbody radiator operating at the temperature of solidification of platinum

CANDLE POWER

luminous intensity as expressed in candelas

CANTHUS

the angle at either end of the slit between the eyelids, specified as outer, or temporal and inner, or nasal

CARCINOMA

cancer, a malignant growth

CATARACT

any opacity of the lens is a cataract; the opacity arises from either denatured protein or imbibition of fluid by the lens. A condition in which the crystalline lens of the eye, or its capsul, or both, become opaque, with consequent loss of visual acuity.

CELLULITS

an inflammation of soft tissues

CENTRAL ANGIOSPASTIC RETINOPHATHY

condition characterized by separation of the neural retina from the pigment epithelium in the macular area by a serous fluid

CENTRAL VISUAL ACUITY

faculty of the eye to perceive the shape and form of objects in the direct line of vision

CENTROCECAL SCOTOMA

area of blindness in the field of vision involving both the fixation point and the blind spot (cecum); characterizes toxic amblyopia

CHARCOTIS TRIAD

nystagmus, intention tremor, and scanning speech, which occur as a late sign in demyelinating disease, particularly multiple sclerosis

CHEMOSIS

edema of the conjunctiva

CHERRY RED SPOT

apparent color change in the fovea (retinal area of sharpest vision). Results from opacification of the inner retinal layers around it, allowing red color of choroidal circulation to stand out. Occurs in central retinal artery occlusion and Tay-Sachs disease

CHOCKED DISC

marked swelling of the optic disk; sometimes due to a brain tumor

CHORIOD

the vascular tissue of the eye, lying between the retina and sclera, and continuous with the ciliary body and iris in front; it furnishes nourishment to the other parts of the eyeball

CHORIORETINITIS

inflammation of the retina and choroid causing seepage from the blood vessels to accumulate on the retina and sometimes the cornea

CHOROIDITIS

inflammation of the choroids

CHROMATIC ABERRATION

imperfection of an image produced by variations in the refractability of the various wavelengths of white light

CILIA

eyelashes

CILLIARY BODY

portion of the vascular coat between the iris and the choroids; it consists of ciliary muscles and is responsible for the change of shape of lens in accommodation

CIRCINATE RETINOPATHY

rare monocular disorder, mainly of elderly women, characterized by girdle-like zone of small, discrete, coalescing white spots engirdling the macular area

COLLYRIUM

eyewash

COLOBOMA

fissure of a part of the eye; means "something is missing"; congenital cleft due to failure of the eye to complete growth in the part affected

COLOR DEFICIENCY

diminished ability to perceive differences in color; usually for red or green, rarely for blue or yellow

COMMISSURE OR OPTIC CHIASN

the union and crossing of the optic nerve

COMMOTIO RETINA

traumatic lesion of the posterior pole with edema and hemorrhage following contusion of the anterior ocular segment

COMPLEMENTARY AFTER-IMAGE

after-image in which the hue is approximately complementary to the hue of the sensation produced by the original stimulus

COMPLEMENTARY CHROMATICITIES

pairs of different samples of light that produce an achromatic (colorless) stimulus when combined in suitable proportions

COMPLEMENTARY COLORS

pairs of samples of light that have complementary chromaticities; also the proper relative amounts of luminous flux to produce an achromatic (colorless) mixture

CONCAVE LENS

a lens with hollowed surfaces like the inner aspect of a sphere; having the power to diverge the rays of light; also known as a reducing glass or minus lens, denoted by the sign (-)

CONES AND RODS

two kinds of cells which form a layer of the retina and act as a light-receiving media. Cones are concentrated at the macula, and decreasing toward the periphery. Cones are concerned with visual acuity and color discrimination; rods, concentrated at the periphery and decreasing toward the macula are concerned, with motion and vision at low degrees of illumination (night vision).

CONGENITAL

present at birth

CONGRUOUS FIELD DEFECTS

visual field defects that are exactly the same in extent and intensity in both eyes; characterizes lesions in the optic radiation and occipital cortex

CONICAL CORNEA

keratoconus

CONJUGATE MOVEMENTS

paired movements, thus when looking at the right, the external rectus muscle of the right eye pairs up with the internal rectus of the left eye

CONJUGATE OCULAR MOVEMENTS

similar ocular movements of both eyes such as eyes right, eyes down, eyes left, eyes up

CONJUNCTIVA

mucous membrane which lines the eyelids and covers the front part of the eyeball

CONJUNCTIVITIS

inflammation of the conjunctiva

CONSENSUAL LIGHT REFLEX

constriction of the pupil in the fellow eye when the retina is stimulated by light

CONTACT OR CORNEAL LENSES

lenses so constructed that they fit directly on the eyeball; used for the correction of vision in cases having a cone-shape cornea and for cosmetic reasons. Corneal lenses are also used after cataract (lens) extraction to replace the lens removed from the eye. They provide less distortion and image size difference from the other eye than spectacles would.

CONUS OF OPTIC DISK

abnormality in which the choroids and retinal pigment epithelium do not extend to the optic disk, allowing the sclera to be observed ophthalmoscopically at its margin

CONVERGENCE

the act of bringing the two eyes inward as in looking at a near object. The process of directing the visual axes of the two eyes to a near point, with the result that the pupils of the two eyes are closer together.

CONVEX LENS

a lens with surfaces like those of part of a sphere, having the power to converge the rays of light and to bring them to focus; also known as a magnifying, hyperoptic or plus lens, denoted by the sign (+)

CORECTOPIA

displacement of pupil from its normal position

CORNEA

the clear transparent portion of the external coat of the eyeball forming the front of the aqueous chamber; also known as the window of the eye

CORNEAL GRAFT

operation to restore vision by replacing a section of the opaque cornea with transparent cornea

CORNEAL ULCER

infiltration of a certain portion of the cornea, followed by suppuration and loss of substance and finally opacity of the spot

CORRESPONDING POINTS

points on the two retinas that have the same directional value in space

COVER-UNCOVER TEST

alternate covering and uncovering of one eye to distinguish between a phoria and tropia

CRALAZION

a cyst or tumor of the eyelid from retained secretion of the Meibomian glands; chronic lipogranuloma of a meibomian gland; inflammatory enlargement of a meibomian gland in the eyelid

CROSS-EYE

a form of strabismus or squint

A and V: cross-eyes in which the eye are closer together in looking up than down (A) or closer looking down than up (V)

CREDE'S PROPHYLAXIS

installation of 1% silver nitrate in the eyes of a newborn infant to prevent gonococcal conjunctivitis

CRYOTHERAPY

procedure carried out with a freezing probe

CRYSTALLINE LENS

a transparent, colorless body suspended in the anterior portion of the eyeball between the aqueous and the vitreous chambers, the function of which is to bring the ray of light to focus

CYCLITIS

inflammation of the ciliary body

CYCLODIALYSIS

surgical procedure for glaucoma to establish a communication between the anterior chamber and the suprachoroidal space

CYCLODIATHERMY

destruction of a portion of the ciliary body by diathermy to reduce the quantity of aqueous humor produced in glaucoma

CYCLOPLEGIA

paralysis of the ciliary muscle giving rise to paralysis of accommodation

CYLCLOPLEGIC

a drug that temporarily paralyses accommodation by putting the ciliary muscle at rest and dilates the pupil; often used to ascertain the error of refraction

CYLINDER

in optics, a lens having no refracting power in one meridian and maximal refracting power at the meridian at right angles to this

CYLINDERICAL LENS

a lens with one surface which is a section of a cylinder (either concave or convex); a lens used for correction of astigmatism

CYST

a growth consisting of fluid within a capsule

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D

DACRYOCYSTORHINOSTOMY

surgical procedure in which mucous membrane of the lacrimal sac is anastomosed with the mucous membrane lining the middle meatus of the nose to establish lacrimal drainage

DACRYOSTENOSIS

abnormal narrow opening of the tear sac

DARK ADAPTATION

the ability of the retina and pupil to adjust to a dim light

DENDRITIC KERATITIS

inflammation of the corneal epithelium by the herpes hominis virus

DENERVATION SUPERSENSITIVITY

sensitivity to neural effect or substance that follows postganglionic interruption of the nerve supply of organs innervated by the autonomic nervous system

DEPTH PERCEPTION

the ability to perceive the solidity of objects and their position in space

DESCEMETOCELE

herniation of the basement membrane of the corneal endothelium

DETACHMENT, RETINAL

separation of the neural retina from the retinal pigment epithelium

DEUTERANOMALY

form of anomalous trichromatism for which there appears to be a deficiency of green-sensitive cones so that there is poor green-purple and red-purple discrimination, green insensitivity, and normal luminosity function

DEUTERANOPIA

form of dichromatism in where there are but two cone pigments present and there is complete insensitivity to green

DEVIATION

eye misalignment caused by extraocular muscle imbalance; one fovea is not directed at the same object as the other. Present even when both eyes are uncovered

Primary: ocular deviation seen in paralysis of an ocular muscle when the noninvolved eye is used for fixation.
Secondary: ocular deviation seen in paralysis of an ocular muscle when the involved eye is used for fixation.

DIALYSIS OF RETINA

separation of the ora serrata of the neural retina from the retinal pigment epithelium

DIAPHANOSCOPY

transillumination of a body cavity, used in ophthalmology to demonstrate the diminution of the pigment in the iris in the female carriers of albinism or in the diagnosis of intraocular tumors

DICHROMATISM

abnormality of color vision in which only two of the three cone pigments are present; mixtures of two, rather than three, components are necessary and sufficient to match all colors (protanopes, red absent; deuteranopes, green absent; tritanopes, blue absent)

DIOPTER

unit of measurement of strength of refractive power of lenses. A lens of one diopter is a lens having a focal distance of one meter, a comparatively weak lens; a two-diopter lens is one having half the focal length of the one-diopter lens or half a meter; a lens of a focal length of four meters is called and 0.25 diopter lens.

DIPOLOPIA

double vision; one object seen as two; double images result when the visual lines of the two eyes are not directed toward the same object, i.e., when one eye deviates (unless the image of the deviating eye is suppressed); double vision simultaneous perception of two grossly dissimilar images.

Crossed double vision: the image arising from the right is observed to the left of the image arising from the left eye; associated with conditions in which the eyes turn outward.
Uncrossed condition: the image of the right eye is to the right of the image belonging to the left eye; observed in conditions in which the visual axes of the eye are directed toward each other as in esotropia.

DISCIFORM DEGENERATION OF MACULA

secondary type of macular degeneration, often arising from abnormalities in the elastic layer of the lamina vitrea.

DISCIFORM DETACHMENT OF RETINA

term commonly applied to separations of the retina in the macular region arising because blood or serous fluid separates the neural retina from the retinal pigment epithelium.

DISCIFORM KERATITIS

stromal type of cornel inflammation, roughly circular in shape, often seen as secondary stromal involvement to herpes simplex keratitis.

DISINSERTION OF RETINA

retinal dialysis at the ora serrata in which the neural retina is separated from the retinal pigment epithemlium.

DISLOCATION OF LENS

condition in which the crystalline lens is completely unsupported by the zonular fibers so that the lens is free, either in the vitreous body or the anterior chamber.

DOYNE'S HONEYCOMB CHOROIDITIS

noninflammatory condition with excrescences (drusen) of the cuticular layer of the lamina vitrea; fundus appears to be studded with yellowish white dots.

DRUSEN

hyaline excrescences of the lamina vitrea.

DRY EYE

keratoconjunctivitis sicca

DUCTIONS

ocular movements of one eye only

DUCTION

a stem word with a prefix to describe turning or rotation of the eyeball (abduction-turning out, adduction-turning in)

DYSLEXIA

psychological abnormality in which despite adequate intelligence, motivation, and, instruction and in the absence of a physical handicap, emotional disturbance, or cultural deprivation an individual fails to master printed and written language.

DYSMETRIA

abnormality of ocular movements in which there is a disturbance in the power to control the range of movement

DYSTROHY, CORNEAL

noninflammatory developmental, nutritional, or metabolic abnormality characterized by the occurrence of opaque material in the central cornea. Salzman's modular inflammatory opacity of the cornea associated with bacterial hypersensitivity, particularly to Mycobacterium tuberculosis.

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E

ECCENTRIC FIXATION

visual abnormality in which a retinal area other than the fovea centralis is used for visual fixation

ECCHYMOSIS

extravagation of blood beneath the skin. A "Black Eye".

ECTASIA

localized bulging of the sclera or cornea. If uveal tissue is involved it is called a staphyloma

ECTROPION

a condition in which there is an eversion (turning inside out) of the eyelids. Turning outward of the margin of the eyelid occurring in spastic, cicatricial, and paralytic forms.

EIKONOMETER

device for measuring the retinal image size in each eye; used in the diagnosis of aniseikonia or a difference in image size of the two eyes, most often arising from a difference in refractive power of the eyes

ELECTRO-OCULOGRAM

ratio of standing potential between retina and cornea in light and dark adaptation

ELECTROMAGNETIC SPECTRUM

range of radiant energy that has a variable frequency and a constant velocity (energy = Planck's constant x frequency)

ELECTRORETINOGRAM

action potential that follows stimulation of the retina

EMMETROPIA

a condition of normal refraction of the eye. The image of distant objects is focused exactly upon the retina when the eye is in a state of rest.

EMPHYSEMA, ORBITAL

air in the orbit; generally follow traumatic rupture of a nasal sinus, particularly the lamina papyracea of the ethmoid bone

ENDOGENOUS UVEITIS

inflammation of the uveal tract arising from causes within the body in contrast to that introduced from outside the body as in injuries (exogenours)

ENDOPHTHALMITIS

inflammation of most of the internal tissues of the eyeball. Purulent inflammation of the intraocular contents.

ENOPHTHALMOS

abnormal recession of the eyeball within the orbit

ENTROPION

a condition in there is an inversion (turning inward) of the eyelid; observed in cicatricial, spastic, and paralytic forms

ENUCLEATION

complete surgical removal of the eyeball

EPIDEMIC KERATOCONJUNCTIVITIS

inflammation of the cornea and conjunctiva by an adenovirus, often adenovirus type 8

EPILATION

removal of hair or eye lashes

EPIPHORA

tearing in which faulty drainage of tears permits their overflow

EPISCLERITIS

localized inflammation of the superficial tissues of the sclera

EPITHELIAL DOWNGROWTH

epithelialization of the interior of the eye that may follow faulty wound healing of the anterior ocular segment

ERYSIPHAKE

instrument that uses a vacuum to grasp the lens in cataract extraction

ESO DEVIATION

inward deviation of the eye

ESOPHORIA

a tendency of the eye to turn inward; latent inward deviation of the eye in which, with binocular vision suspended, the eyes deviate inward

ESOTROPIA

a manifest turning inward of the eye (convergent strabismus or crossed eye)

ESSENTIAL ATROPHY OF IRIS

rare, progressive unilateral disease of the iris in which there is a patchy loss of all layers of the iris, causing a distorted and migrating pupil and often a secondary increase in intraocular pressure.

ETHMOID SINUS

the cavities of air cells within the ethmoid bones; behind the bridge of the nose

EVISCERATION

in ophthalmology, the surgical procedure in which the intraocular contents are removed, retaining the cornea (sometimes) and the sclera

EXOTROPIA

abnormal turning outward from the nose of one or both eyes (divergent strabismus)

EXCITING EYE

in sympathetic opthmalmia, the injured eye from which the irido-cyclitis is transferred to the uninjured eye

EXENTERATION, ORBITAL

removal of all of the orbital tissues, including the eye and its nervous, vascular, and muscular connections

EXFOLIATION OF LENS CAPSULE

condition in which the anterior lens capsule degenerates and appears to be wiped from the lens by the movement of the iris; true exfoliation follows infra red injury to the lens; pseudoexfoliation is more common; the cause is unknown

EXODEVIATION

turning outward of the eyes

EXOPHORIA

latent outward deviation of the eyes in which, with binocular vision suspended, the eyes deviate outward

EXPOPHTHALMOS

abnormal profusion of the eyes

Endocrine: associated with abnormalities of the thyroid gland
Ophthalmoplegic: inability to move the eye because of exophthalmos
Pulsating: associated with a carotid-cavernous fistula

EXOTROPIA

abnormal turning outward from the nose of one or both eyes (divergent strabismus, a manifest deviation)

EXTERNAL RECTUS MUSCLE

one of the six extrinsic muscles of the eye; it moves the eye outward towards the temple

EXTRINSIC MUSCLES

the six external muscles of the eye which move the eyeball; each eye has four recti and two oblique muscles

EYE

sense organ for sight. Receives light imagery and transmits the visual information to the brain. Composed of three major structural layers (corneo-sclera, uvea and retina) and includes the lens, aqueous and vitreous

EYE DOMINANCE

tendency of one eye to assume to major function of seeing, being assisted by the less dominant eye

EYE GROUNDS

Fundi or interior of the eye, i.e., optic nerves, retina, etc. See Fundus.

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F

FIELD OF VISION

the entire area which can be seen without shifting the gaze, usually measured by means of an arc (perimeter) located 330 mm. from the eye

FLARE, AQUEOUS

see Aqueous Flare

FLOATER

object seen in the field of vision that originates in the vitreous body; the most common floaters are muscae volitantes, minute flects of protein seen in bright, uniform illumination

FLUORESCENCE

reradiaton of energy with increase of wavelength by an absorbing substance

FLUX

short form of radiant flux, or luminous flux, according to context

FOCUS

point to which rays are converged after passing through a lens; focal distance is the distance rays travel after refraction before focus is reached

FOOT-CANDLE

unit of illuminance equal to one lumen incident per square foot

FOOT-LAMBERT

unit of luminance

FORNIX

a loose fold of the conjunctiva where the part covering the eyeball meets the conjunctiva lining of the eyelid

FOVEA

small depression in the retina at the back of the eye; the part of the macula adapted for most acute vision

FRUCTOSE 1-0ALDOLASE DEFICIENCY

enzymatic deficiency associated with amaurotic familial idiocy in the homozygote; parents of such children are heterozygotes and have a much less severe enzyme deficiency

FUNDUS

the back of the eye which can be seen with an ophthalmoscope

FUNDUSCOPE

inasmuch as many organs have a fundus, a more precise term for the instrument used in ophthalmoscopy is ophthalmoscope

FUSION

the power of coordinating the images received by the two eyes into a single mental image

Grade 1 simultaneous macular perception (normal correspondence): ability of the brain to receive and appreciate images from the fovea of each eye simultaneously
Grade 2 fusion with amplitude: blending of the similar images from the two foveas into a single perception
Grade 3 stereopsis: blending of slightly dissimilar images from the two eyes with the perception of depth

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G

GLARE: sensation produced by brightnesses within the visual field that are sufficiently greater than the luminance to which the eyes are adapted to cause annoyance, discomfort, or loss in visual performance and visibility
GLASSES: popular name for spectacles or eyeglasses
GLAUCOMA: increased pressure inside the eye
GLIOMA: malignant tumor of the retina
GONIOPUNCTURE: surgical procedure for the treatment of congenital glaucoma; a small opening is made in the inside meshwork of the eye allowing drainage of the aqueous fluid into the subconjunctival space
GONIOSCOPE: a magnifying device used in combination with strong illumination and a contact glass for examining the angle of the anterior chamber
GONIOTOMY: operation for congenital glaucoma in which the trabecular meshwork in the region of Schlemm's canal is incised

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H

HALLUCINATIONS

perception without external stimulus that may occur in every field of sensation; visual hallucinations are formed when composed of scenes and unformed when composed of sparks, lights, and the like; formed hallucinations characterize temporal lobe disturbances and unformed visual hallucination characterize occipital lobe disorders, particularly migraine

HASSALL-HENLE BODIES

small white hyaline outgrowths on the cornea that occur as a sign of aging

HEMIANOPSIA

blindness of one-half the field of vision of one or both eyes

HETEROCHROMIA OF IRIS

condition in which the irises of the two eyes are not of uniform color

HETEROPHORIA

a constant tendency of the eyes to deviate from the normal position for binocular fixation

HETEROTROPIA

an obvious or manifest deviation of the visual axis of an eye out of alignment with the other eye. Syn. Cross-eye; strabismus

HIPPUS

spasmodic dilation and contraction of the pupil; particularly noticeable with stimulation of light

HISTOPLASMOSIS

infection due to yeast-like fungus organism; caused by inhalation or ingestion of spores of the organism (found in soil or dried excrement of animals)

HOLMGREN'S COLOR TEST

color vision test utilizing colored yarns

HOMONYMOUS

located on the same side; usually refers to visual field defects

HORDEOLUM

a stye; acute inflammation caused by infection of one of glands an eyelash; if chronic it is called chalazion

HOROPTER

plane in space that localizes the visual direction of corresponding retinal points

HUDSON-STAHLI LINE

brown line of iron deposit in the cornea

HYDROPHTHALMUS (CONGENITAL GLAUCOMA)

a rare congenital defect in which the eyeball is abnormally large caused by glaucoma in a young, stretchable eye

HYDROPS OF IRIS

term applied to the vacuolization of the pigment layer of the iris as occurs when these cells are filled with glycogen in diabetes mellitus

HYPEREMIA

increased blood flow

HYPEROPE

a farsighted person

HYPEROPIA, HYPERMETROPIA (FARSIGHTEDNESS)

a refractive error in which, because the eyeball is short or the refractive power of the lens is weak, the point of focus for rays of light from distant objects (parallel light rays) is behind the retina; thus, the accommodation to increase the refractive power of the lens is necessary for distant as well as near vision

Absolute: the amount of hyperopia remaining after the eye exerts its maximal ability to accommodate
Axial: caused by abnormal shortness of the anteroposterior diameter of the eye
Latent: portion of total hypermetropia that cannot be overcome, or the difference between the manifest and total hypermetropia
Manifest: amount of hypermetropia indicated by the strongest convex lens a patient will accept with retaining normal visual acuity
Total: entire hypermetropia, both latent and manifest

HYPERPHORIA

tendency for the eyes to deviate vertically which is prevented by binocular vision

HYPERTELORISM

excessive width between two organs; in ocular hypertelorism there is increased distance between the eyes that is often associated with mental deficiency and exotropia (outward eye deviation)

HYPERTENSION

high blood pressure (due to disease of the arteries, kidney, or heart and other causes)

HYPERTROPHY

increase in the size of an organ

HYPERTROPIA

deviation of the eyes in which one eye is higher than the other

HYPOTONY, OCULAR

diminished ocular pressure

HYSTERICAL AMBLYOPIA

a form of temporary psychic blindness occurring in hysteria

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I

ILLUMINANCE

luminous flux incident per unity of a surface

IMAGE

visual impression of an object formed by a lens or mirror

False: in double vision, the image arising in the deviating eye
Purkinie's: images reflected from the surface of the cornea, the anterior surface of the lens, and the posterior surface of the lens
Real: in optics, the inverted image in which refracted rays pass through the image point
True: in double vision, the image received by the non-deviating eye
Virtual: in optics, the erect image in which the refracted rays do not pass through the image point, but appear to come from it

INCONGRUOUS FIELD DEFECTS

visual field defects that are dissimilar in the two eyes; occur in lesions involving that portion of the visual pathways anterior to the lateral geniculate body

INFERIOR OBLIQUE MUSCLE

one of the six extrinsic muscles of the eye; it moves the eye up and out and rotates it outward

INFERIOR RECTUS MUSCLE

one of the six extrinsic muscles of the eye; it moves the eye down

INFRARED RADIATION

portion of the electromagnetic spectrum that has a wavelength of more than 700nm and less than 10,000nm

INJECTION

a term sometimes used to mean congestion of ciliary or conjunctival blood vessels, redness of the eye

INTERNAL RECTUS MUSCLE

one of the six extrinsic muscles of the eye; it moves the eye inward towards the nose

INTERSTITIAL KERATITIS

a form of inflammation of the middle layer of the cornea; found chiefly in children and young adults, usually caused by transmission of syphilis from mother to unborn child

INTRASCLERAL NERVE LOOP

condition in which a long posterior ciliary nerve loops in the anterior sclera; gives rise to a minute dark spot of uveal tissue on the sclera

IRIDECTOMY

cutting out a part of the iris

Peripheral: removal of a portion of the peripheral iris
Sector: removal of an entire sector, extending usually from the papillary margin to the root of the iris

IRIDENCLEISIS

surgical procedure creating a permanent drainage route from the anterior chamber by wedging iris tissue into a limbal incision to act as a wick

IRIDOCAPSULOTOMY

surgical procedure in which the iris and adherent lens capsule is incised to create a new papillary opening; procedure is necessitated by a cataract extraction in which a large amount of lens capsule remains

IRIDOCYCLITIS

inflammation of the iris and the ciliary body

IRIDODIALYSIS

separation of the base of the iris from the ciliary body; main cause is blunt trauma to the eye

IRIDODONESIS

iris that flops loosely due to lack of normal support from the lens; follows removal or dislocation of lens

IRIDOPLEGIA

paralysis of the iris sphincter

IRIS

colored, circular membrane, suspended behind the cornea and immediately in front of the lens. The iris regulates the amount of light entering the eye by changing the size of the pupil.

IRIS BOMBE'

condition in which the pupil is adherent to the lens so that aqueous humor accumulates in the posterior chamber; iris tends to balloon forward peripherally and it may close the angle, causing secondary glaucoma

IRIS COLOBOMA

iris defect that leaves a gap in the iris tissue; follows iridectomy or occurs as a congenital abnormality

IRITIS

inflammation of the iris; the condition is marked by pain, congestion in the ciliary region, photophobia, contraction of the pupil discoloration of the iris, and is caused by injury, syphilis, rheumatism, gonorrhea, and tuberculosis

ISHIHARA COLOR PLATES

a test for color blindness; based on the ability to trace patterns in a series of multicolored charts

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J

JAEGER TEST: a test for near vision; lines of reading matter printed in a series of various sizes of type
JOULE: unit of energy; ten million ergs; used in comparing lasers or laser beams

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K

KAYSER-FLEISHER RING

golden deposit of cooper in the periphery of the cornea observed in hepatolenticular degenerations (Wilson's disease)

KERATECTOMY

removal of the cornea

KERATIC PRECIPITATES

clumps of leukocytes adhering to the corneal endothelium in uveal tract inflammation; customarily divided into mutton-fat (macrophages), which occur in granulomatous inflammations, and punctuate (lymphocytes), which occur in non-graulomatous inflammations

KERATITIS

inflammation of the cornea; loss of luster and transparency and cellular infiltration

KERATOCELE (descemetocele)

hernia of Descement's membrane through the cornea

KERATOCONJUNCTIVITIS

simultaneous inflammation of the cornea and conjunctiva

KERATOCONUS

cone-shaped deformity of the cornea; a conical profusion of the cornea

KERATOMALACIA

a degenerative softening of the cornea, often occurring in severe Vitamin A deficiency

KERATOME KNIFE

with a triangular blade used for corneal incision

KERATOMETER

instrument for measuring the radius of curvature of the cornea

KERATOMYCOSIS

gray pus-producing corneal ulcer with irregular borders as a result of fungus infection

KERATOPLASTY

transplantation of a portion of the cornea

Lamellar: outer layers are replaced.
Penetrating: entire thickness of a portion of the cornea is replaced.

KERATOPLASTY

See "Corneal Graft"

KERATOTOMY

incision of the cornea carried out in year past to limit the spread of an ulcer

KOEPPE NODULE

accumulation of the epitheloid cells at the papillary margin in granulomatous uveitis

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L

LACRIMAL GLAND

gland which secretes tears; it lies in the outer angle of the orbit

LACRIMAL SAC

the dilated upper end of the lacrimal duct

LACRIMATION

excessive secretion of tears

LAGOPHTHALMOS

condition in which the globe is not entirely covered with the eyelids closed

LAMBERT

unit of luminance

LASER

acronym for light amplification by stimulated emission of radiation; the laser produces a nearly monochromatic and coherent beam of radiation

LENS

a refractive medium having one or both surfaces curved; in the lens of the eye both surfaces are curved; glass or other transparent material is used optically to modify the path of light

Bifocal: spectacles that contain two foci, usually arranged with the focus for distance above and a smaller segment for near below; such lenses are used in the correction of presbyopia and to relieve excessive accommodation in accommodative strabismus of children
Colored: selectively absorb or reflect certain wavelengths of light
Contact: worn beneath the lids
Crystalline: transparent biconvex tissue located behind the pupil and in front of the vitreous
Prism: transparent solid with triangular ends and two converging sides; separates white light into its spectral components and bends rays of light toward its base; used to measure or to correct ocular muscle imbalance
Safety: lens resistant to shattering made either of plastic or by means of casehardening

LENSOMETER

instrument for determining the refractive power of lens

LENTICONUS

rare abnormality of the lens characterized by a cone-shaped protrusion of the lens, usually on the front surface

LEUCOMA OR LEUKONA

a whitish opacity of the cornea. A less marked opacity is a macula, and the most minor type of opacity is a nebula.

Adherent: corneal opacity to which the iris is adherent

LIGHT

that portion of the electromagnetic spectrum that gives rise to a sensation, through stimulation of the retina

LIGHT ADAPTATION

the power of the eye to adjust itself to variations in the amount of light

LIGHT PERCEPTION (LP)

ability to distinguish light from dark

LIMBUS

the junction of the cornea and the sclerotic coat or white of the eye

LOW VISION AIDS

optical devices of various types useful to persons with vision impairment

LUMEN

unit of luminous flux equal to the flux in a unit of solid angle (one steradiam) from a uniform point source of one candela

LUMINANCE

amount of light emanating from an object and producing a sensation of brightnes

LUMINOSITY

ratio of lumens per watt of any kind of radiant energy

LUMINOUS EMMITTANCE

density of luminous flux emitted from a surface

LUMINOUS FLUX

rate of flow of luminous energy

LUX

unit of illuminance equal to one lumen per square meter

LYSOZYME

antibacterial enzyme found in tears, leukocytes, egg albumin, and plants; mainly effective against nonpathogenic bacteria

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M

MACROPHTHALMOS

abnormally large eyeball, resulting chiefly from infantile glaucoma

MACULA

minute corneal opacity

MACULA LUTEA

the small area of the retina that surrounds the fovea and with the fovea comprises the area of distance vision. Syn. Yellow spot.

MEGALOCORNEA

front third of the eye (cornea) is larger than normal (12 mm or more)

MEGOPHTHALMOS

abnormally large eyeball present at birth (congenital)

MEIOBONIAM GLANDS

sebaceous glands of the eyelids

MICROCORNEA

abnormally small cornea, having a diameter of less than 9 mm

MICROPHAKIA

anomaly in which the crystalline lens is abnormally small

MICROPHTHALMIA

condition in which the eyeball is abnormally small

MICROPSIA

disturbance of visual perception in which objects appear smaller than their true size

MICROSCOPIC GLASSES

magnifying lenses arranged on the principal of a microscope, occasionally prescribed for persons with very poor vision

MILLIMICRON

unit of wavelength equal to 10-9 meter; nanometer now preferred term

MIOSIS

condition in which the pupil is constricted

MIOTIC

small pupils

MONOCULAR

relating to one eye as opposed to binocular, which involves both eyes

MORGAGNIAN CATARACT

hypermature cataract, in which the cortex is liquefied, permitting the lens nucleus to float within the capsule

MUSCAE VOLITANTES

flitting flecks darting about in the field of vision caused by opacities in the vitreous humor or erythrocytes in retinal capillaries

MYDRIASIS

increase of pupil size (dilation)

MYDRIATIC

an agent which causes dilation of the pupil

MYOPE

a near-sighted person

MYOPIA

nearsightedness, a refractive error in which, because the eyeball is too long, the point of focus for rays of light from distant objects (parallel light rays) is in front of the retina; thus, to obtain distant vision, the object must be brought nearer to take advantage of divergent light rays (those from objects less than twenty feet away)

Axial: caused by abnormal length of anteroposterior diameter of the eye
Degenerative: stretching of eye structures, with thinning and tearing of sclera, choroid, retinal pigment epithelium and retina, especially in the macular area
Refractive: caused by overpowered optical elements in the eye

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N

NAGEL ANOMALOSCOPE

device for mixing two colors to match a third; used for analysis of color perception

NANOMETER (NM)

unit of wavelength equal to 10-9 (one one-billionth) meter; formerly called millimicron (mu)

NARROW-ANGLE GLAUCOMA

glaucoma arising because opposition of the iris to the peripheral cornea prevents the aqueous humor from draining through the trabecular meshwork

NEAR POINT OF ACCOMMODATION

the nearest point at which the eye can perceive an object distinctly. It varies according to the power of accommodation

NEAR POINT OF CONVERGENCE

the nearest single point at which the two eyes can direct their visual lines, normally about three inches from the eyes in young people

NEAR VISION

ability to perceive objects clearly at normal reading distance (usually considered to be approximately fourteen inches from the eyes)

NEBULA OF CORNEA

minor opacity of the cornea

NEUROTROPHIC KERATITIS

corneal inflammation arising because of trama to the cornea

NIGHT BLINDNESS

a condition in which the sight is good by day, but deficient at night and in any faint light

NODAL POINTS

locations in an optical system toward and from which are directed corresponding incident and transmitted rays that make equal angles with the optic axis

NYSTAGMUS

an involuntary, rapid movement of the eyeball; it may be lateral, vertical, rotary, or mixed

End-position: involuntary rhythmic movement of the eyes observed when in extreme positions of gaze
Jerk: occurs with a fast and a slow pace
Labyrinthine: occurs when the labyrinths are irritated or diseased (synonym, vestibular nystagmus)
Miner's: nystagmus caused by darkness
Optokinetic: occurs in normal individuals when a succession of moving objects traverse the field of vision such as occurs when gazing out the window of a moving vehicle at a succession of stationary objects (synonym, railroad nystagmus)
Pendulous: occurs when vision in both eyes has been defective since birth
Rotary: eyeball partially rotates around the visual axis

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OCULIST or OPHTHALMOLOGIST

a physician (M.D.) who specializes in diagnosis and treatment of defects and diseases of the eye, performing surgery when necessary or prescribing other types of treatment, including glasses

OCULAS DEXTER

(O.D.) right eye

OCULAS SINISTER

(O.S.) left eye

OCULUS UTERQUE

(O.U.) both eyes

OPHTHALMIA

inflammation of the eye or conjunctiva

OPHTHALMIA NEONATORUM

an acute purulent conjunctivitis of the newborn; gonorrheal inflammation of the eyes of the newborn from the birth canal

OPHTHALMOLOGIST

a physician who specializes in diseases of the eye

OPHTHALMOPLEGIA

paralysis of the ocular muscles

External: paralysis of the external ocular muscles
Internal: paralysis of the muscles of the iris and the ciliary body
Total: combination of both intrinsic and extrinsic paralysis

OPHTHALMOSCOPE

illuminated instrument for examining the interior of the eye

Direct: provides an upright image of about 15 diameters magnification
Indirect: convex lens is held in front of the eye as an inverted image is observed; provides a magnification of about four times but allows examination of a more peripheral portion of the fundus than direct ophthalmoscopy

OPTIC ATROPHY

atrophy of the optic nerve

OPTIC CHIASM

the crossing of fibers of the optic nerves on the ventral surface of the brain.

OPTIC DISK

head of the optic nerve in the eyeball

OPTIC NERVE

the special nerve of the sense of sight which carries messages from the retina to the brain

OPTICIAN

one who grinds lenses, fits them into frames, and adjusts the frames to the wearer

OPTOMETRIST

a licensed, nonmedical practitioner (OD), specializing in vision problems, treating vision conditions with spectacles, contact lenses, low vision aids and vision therapy, and prescribing medications for certain eye diseases

ORBIT

the bone cavity containing the eye; the eye socket

ORTHOPHORIA

tendency for the eyes to be parallel, normal ocular muscle balance

ORTHOPITIC TRAINING

fusion training, series of scientifically planned exercises for developing or restoring the normal fusion teamwork of the eyes

ORTHOPTICS

technique of providing correct and efficient visual responses, usually by the form of visual training; these measures include the treatment of functional amblyopia, management of convergence insufficiency, and diagnosis of muscle imbalance and strabismus

ORTHOPTIST

one who provides orthoptic training

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P

PALPEBRAL

pertaining to the eyelid

PANNUS

invasion of the cornea by infiltration of lymph and formation of new blood vessels

PANUM'S AREA

spatial area surrounding the horopter in which objects are viewed with stereopsis; outside this area, diplopia occurs

PAPILLA

a small elevation

Lacrimal: slight elevation on eyelid margin near the nose; particularly evident in the elderly
Optic disk: a misnomer in that the disk does not project into the eye

PAPILLEDEMA

swelling of the optic disk with engorged blood vessels, associated with elevated pressure within the skull

PAPILLITIS

inflammation of the optic disk or optic neuritis

PARTIALLY SEEING CHILD

for educational purposes, a partially seeing child is one who has a visual acuity of 20/70 or less in the better eye after the best possible correction, and who can use vision as the chief channel of learning

PERIMETER

an instrument of measuring the field of vision

PERIPHERAL VISION

ability to perceive presence, motion, or color of objects outside of the direct line of vision; the vision of the retinal outside the macula area

PHAKOMATOSES

group of hereditary diseases characterized by the presence of spots, tumors, and cysts in various parts of the body; types recognized as associated with ocular findings are tuberous sclerosis, Lindau-von Hippel disease, von Recklinghausen's disease, Bourneville's disease, and Louis-Bar disease

PHORIA

a root word denoting a latent deviation in which the eyes have a constant tendency to turn from the normal position for binocular vision; used with prefix to indicate the direction of such deviation (hyperphoria, exophoria, exophoria)

PHOTOPHOBIA

abnormal sensitivity to and discomfort from light

PHOTOPSIA

subjective sensation of sparks and flashes of light that occur in some pathologic conditions of the optic nerve, the retina, or the brain

PHTHSIS BULBI

degenerative shrinkage of the eyeball

PILOCARPINE

a drug used in ophthalmology to contract the pupil and to reduce ocular tension

PINGUECULA

a small yellowish white subconjunctival elevation composed of elastic tissue; may occur on either side of the cornea

PINK EYE / CONJUNCTIVITIS

a contagious inflammation of the conjunctiva

PITS IN OPTIC DISK

coloboma of the optic disk causing poor vision, sometimes associated with central serous chorioretinophathy

PLACIDO'S DISK

device composed of concentric black and white lines that are reflected onto the anterior surface of the cornea to detect astigmatism

PLEOPTICS

a method of treating amblyopia through the use of instruments which restore fixation to the fovea by direct stimulation or by the production and correct localization of afterimages

POLIOSIS

condition characterized by the absence of pigment in the hair; poliosis of the eyelashes occurs in sympathetic ophthalmia, syphilis, and Vogt-Koyanagi's-Harada syndrome

POLYCORIA

more than one pupil in the iris

POSTERIOR CHAMBER

space between the back of the iris and the front of the vitreous; filled with aqueous

PRESBYOPIA

a gradual lessening of the power of accommodation due to a physiological change (hardening of the lens) which becomes noticeable after the age of forty

PROSTHESIS

an artificial substitute for a missing eye (or other missing part of the body)

PROTANOMALY

form of anomalous trichromatism for which, in a red-green mixture, more than the normal amount of red is required than for normal observer

PROTANOPE

person having protanopia

PROTANOPIA

form of discoloration in which red and bluish green are confused, and relative luminosity of red is much lower than for normal observer

PSEUDO-ISOCHROMATIC CHARTS

charts with colored dots of various hues and shades indicating numbers, letters or patterns, used for testing color discrimination

PSEUDO-ISOCHROMATIC PLATE

see Ishihara color plates

PTERYGIUM

a triangular fold of growing membrane which may extend toward the cornea on white of the eye. It occurs most frequently in persons exposed to dust or wind.

PTOSIS

a paralytic drooping of the upper eyelid. See Blepharoptosis.

PUNCTA

a small opening on the inner surface of the lids at the nasal angle leading into the lacrimal duct

PUPIL

variable sized black circular opening in the center of the iris that regulates the amount of light that enters the eye

Adie's: abnormality in the reaction of the pupil to light and associated with hypotonic deep reflexes
Argyll Robertson: pupil that does not constrict to light, but constricts to accommodation; pupils are small, unequal in size, and irregular; seen mainly in tabes dorsalis
Cat's Eye: pupil with a white reflex when light is directed into it; most commonly associated with retinoblastoma

PUPILLARY MEMBRANCE

anomaly of the iris, usually minor, in which there is failure of the fetal papillary membrane to atrophy; often persistent strand extends between the iris collarette and the anterior lens capsule

PURKINJE SHIFT

luminosity curve of dark-adapted individual peaks at 500 nm. Whereas the luminosity curve of light-adapted individual peaks at 550 nm, indicates two types of retinal photoreceptors

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R

RECTI MUSCLES

four of the extrinsic muscles of the eye, namely, the internal, external, superior, and inferior rectus muscles

RED EYE

lay term applied to any condition with dilation of conjunctival or ciliary blood vessels

REFLEX

involuntary, invariable, adaptive response to a stimulus

Accommodation: constriction of the pupils when the eyes converge for near vision; an associated reaction and not a reflex
Auditory: brief closure of the eyelids resulting from a sudden sound
Conjunctival (lid): closure of the eyelids induced by touching the cornea (also called Corneal Reflex).
Consensual Light: constriction of the pupil when the opposite retina is stimulated with light
Direct: light contraction of the sphincter pupillae induced by stimulation of retina with light (also called Pupillary Relex)
Eyeball Compression (oculo-cardiac): decrease of heartbeat caused by pressure on the eyeball
Fixation: involuntary eye movement that positions the eye to image a viewed object on the fovea
Foveal: tiny optical reflection from the concave mirror like surface of the foveal depression in the retina. Visible with an ophthalmoscope
Red: glow of light seen to emerge from the pupil when the interior of the eye is illuminated

REFRACTION

deviation of rays of light when passing from one transparent medium into another of a different density. The optical adjustment of the eye when in a state of rest; the ability of the eye to bring parallel ray to a sharp focus on the retina; determination of the refractive errors of the eye and their correction by glasses.

REFRACTIVE MEDIA

the transparent parts of the eye having refractive power; cornea, aqueous, lens, and vitreous

RETINA

innermost coast of the eye, formed of sensitive nerve fibers and connected with the optic nerve. Thin nerve membrane by means of which we see, being an expansion of the optic nerve. It lies between the vitreous and the choroid.

RETINAL DETACHMENT

separation of the retina from the choroid

RETINAL HOLE

break in the continuity of the neural retina so that there is a communication between the vitreous cavity and the potential space between the neural retina and the retina pigment epithelium

RETINITIS PIGMENTOSA

a hereditary degeneration and atrophy of the retina. Night blindness, usually in childhood, is followed by loss of peripheral vision progressing to tunnel vision and finally blindness

RETINOBLASTOMA

common autosomal dominant malignant retinal tumor of infancy. Probably always congenital, occurs in children, sometimes in one eye, at times in both, occasionally in successive children of same family

RETINOPATHY

a disease of the retina, due to various causes

RETINOPEXY

surgical procedure to correct retinal detachment by means of diathermy (heat) or cryo (cold)

RETINOSCHISIS

retinal abnormality in which the neural retina splits at the level of the bipolar layer

RETINOSCOPE

an instrument for determining the refractive state of the eye by observing the movements of lights and shadows across the pupil by the light thrown onto the retina from a moving mirror

RETINOSCOPY

measuring an eye's refractive error by using an retinoscope

RETROBULBAR NEURITIS

inflammation of the optic nerve occurring without involvement of the optic disk

RETROLENTAL FIBROPLASIA

Obsolete term for retinopathy of prematurity. It is characterized by prematurity and oxygen concentrations exceeding 40 percent with resultant retinal degeneration and detachment. Complications such as total retinal separation, glaucoma, and atrophy may follow.

RODS

together with cones are receptors of the optic nerve; the light perceiving layer of the retina; increase in number going from the fovea toward the periphery; are not differentially sensitive to various colors; stimulation of the rods produces only discrimination gray

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S

sc (SIN CORRECTION)

without correction; that is, not wearing glasses

SAFETY GLASSES

impact resistant; available with or without visual correction for workshop or street wear protection, for both adults and children

SALMON PATCH

central area of intense vascularization that occurs in interstitial keratitis with the confluence of all blood vessels at the center of the cornea

SARCOMA

a malignant tumor

SATTLER'S VEIL

swelling and clouding of superficial layers of the cornea, particularly that following prolonged wearing of a contact lens

SCHIRMER'S TEST

test of tear formation in which filter paper is folder over the lid margin and the amount of wetting in 4 minutes is measured in millimeters

SCLERITIS

inflammation of the sclera

SCLEROMALACIA

softening and thinning of the; usually associated with severe rheumatoid arthritis

SCLEROSING KERATITIS

inflammation of the cornea in which it becomes white and opaque resembling the sclera

SCOTOMA

a blind or partially blind area in the visual field

SCOTOPIC ADAPTATION

adaptation to low levels of light at which only rod vision is operative

SEROUS CHORIORETINOPATHY

term applied to limited separation of the sensory layer of the retina from the pigment epithelium layer by fluid

SIDEROSIS BULBI

chronic inflammation of the eye due to a retrained iron foreign body within the eye

SLIT LAMP

see Biomicroscope. Provides a narrow slit beam of light like a searchlight, used with a binocular microscope for examination of the anterior portion of the eye.

SNELLEN CHART

a chart for testing central visual acuity, in which the letters or symbols are drawn to the Snellen Scale of Measurements, in such a away that the uppermost letter is designed to be read by the normal eye at 200 feet; rows of letters follow which should be at 100, 70, 50, 40, 30, 20, 15 and 10 feet

SNELLEN LETTER

letter so constructed that at a given distance from the eye it subtends an angle of 5 minutes, with each portion of the letter subtending an angle of 1 minute

SPHERICAL LENS

segment of sphere refracting rays of light equally in all meridians

SQUINT

cross-eyes (strabismus)

STAPHYLOMA

bulging of the eye surface that includes part of the uvea into an area of thin stretched sclera

STEREOSCOPE

an instrument for the fusion of two separate pictures in such a way as to produce a single picture having the appearance of solidity and length

STEROSCOPIC VISION

ability to perceive relative position of objects in space without such cues as shadow, size, and overlapping

STILES CRAWFORD EFFECT

light passing through the center of the pupil of the eye is more effective in evoking the sensation of brightness than the same amount of light passing through an equal area near the edge of the pupil

STRABISMUS

eye misalignment; failure of the two eyes to direct their gaze at the same object because of muscle imbalance

Comitant: deviation of the eyes in which there is no ocular muscle paralysis and the degree of crossing is the same in all directions of gaze
Noncomitant (incomitant): degree of misalignment varies in different positions of gaze because an extraocular muscle is paretic, paralytic, or restricted

STROMA

supporting tissues of an organ

STYE

acute inflammation of the sebaceous gland in the margin of the eyelid, due to infection and usually resulting in the formation of pus. See Hordeolum

SUBCONJUNCTIVAL HERMORRAGE

bleeding beneath the neural retina and the vitreous body; a meniscus level is often present

SUBLUXATION OF LENS

condition of the lens when a portion of the supporting zonule is absent and the lens lacks support in one or more quadrants

SUPERIOR OBLIQUE MUSCLE

one of the six extrinsic muscles of the eye; it moves the eye down and out and rotates it inward

SUPERIOR RECTUS MUSCLE

one of the six extrinsic muscles of the eye; it moves it up

SUPRESSION

physiologic mental process whereby the retinal image transmitted by one eye is ignored

SYMBLEPHARON

adhesion between palpebral and bulbar conjunctiva

SYMPATHETIC OPHTHALMIA

granulomatous uveitis that follows in the opposite eye when there are penetrating injuries of one eye; the eye secondarily affected is called the sympathizing eye, while the injured eye is called the excited or activating eye

SYNECHIA

adhesion, usually of the iris to cornea or lens

SYNDROME

a group of symptoms and signs that occur together; disease of definite morbid process having a characteristic sequence of symptoms; may affect the whole body or any of its parts

Anton: form of anosognosia in which the patient denies his blindness; usually accompanied by confabulation, with the patient claiming to see objects in the blind field
Bassen-Kornzweig: progressive ataxic neuropathy associated with retinal pigmentary degeneration and a crenated appearance of erythrocytes (A-beta-lipoproteinemia)
Batten-Mayou: juvenile form of amaurotic familial idiocy with macular degeneration and optic atrophy
Behcet: chronic inflammation and vascular lesions in the mucous membranes of the mouth and genitalia. Eye findings include severe uveitis, optic neuritis, and iridocyclitis
Behr: macular degeneration seen in adult life
Benedikt: Paralysis of one eye accompanied by paralysis and tremor of the arm on other side of the body
Berlin: retinal edema following ocular contusion
Best: hereditary type of vitelliruptive macular degeneration characterized by a macular lesion having an ophthalmoscopic appearance of an egg fried "sunny side up" and associated in this stage with good vision; when egg is "scrambled," vision deteriorates
Bielschowsky-Jansky: diffuse nervous system, lesions in the macula, and optic nerve degeneration
Bowen: slow-growing, malignant tumor, commonly arising at multiple sites near the limbus (corneo-scleral junction) but limited to epithelial layer
Cavernous Sinus: thrombosis of the cavernous sinus with third, fourth, and sixth cranial nerve palsy and edema of the face and eyelids and infection
Cerebellopontine angle tumor: ataxia, tinnitus, deafness, ipsilateral paralysis of sixth and seventh cranial nerves, involvement of the fifth cranial nerve, vertigo, and nystagmus
Chiasmal: blind areas in the outer half of the visual field in both eyes
Coats: chronic progressive retinal abnormality characterized by retinal deposits and malformation of retinal blood vessels
Cogan: corneal disorder characterized by abnormal growth of blood vessels into mid-corneal layers, severe inflammation of iris and ciliary body, and deafness
Crocodile Tears: spontaneous lacrimation that occurs with the normal salivation of eating; follows facial nerve paralysis and is due to aberrant regenerating nerve fibers so that some destined for the salivary glands go the lacrimal gland
Crouzon: craniofacial dysostosis with eyes widely separated
Danlos-Ehlers: widespread systemic disorder with overextensibility of joints, hyperelasticity of the skin, fragility of the skin, and pseudotumors following trauma; there may be epicanthal folds, esotropia, blue sclera, glaucoma, ectopic lenses, and proliferating retinopathy
Devic: paraplegia and inflammation of both optic nerves, causing marked vision loss
Down's: eye signs include mongoloid slant, Brushfield spots in iris, cataracts, esotropia, myopia, blepharitis, and keratoconus
Duane's Retraction: eye muscle abnormality characterized by inability to move one eye outward past the midline and retraction of that eye into the orbit, with narrowing of the eyelid fissure on attempted movement of the at eye toward the nose
Eales: vasculitis of the retinal vessels characterized by inflammation, occlusion, neovascularization, and recurrent retinal hemorrhages, occurring particularly in young men
Familial Autonomic Dysfunction (Riley-Day): reduced or absent tears, postural hypotension, excessive sweating, corneal anesthesia, exotropia, and absence of taste buds
Foster Kennedy: optic atrophy on the side of the lesion and papilledema on the opposite side that occur in tumors on the frontal lobe of the brain
Foville: paralysis of the limbs on one side of the body and of the face on the opposite side together with loss of power to rotate the eyes to that side
Fuchs: inflammation of the iris and ciliary body, and secondary cataract
Gaucher's: genetic deficiency of enzyme B-glucosidase. Eye signs include yellowish-brown fleshy conjunctival deposits, corneal clouding, and macular degeneration
Gradenigo: palsy of the lateral rectus muscle and severe unilateral headache in supportive disease of the middle ear
Gronblad-Strandberg: angioid streaks under the retinal due to damage in Bruch's membrane, and macular hemorrhages and scarring
Hand-Shuller-Christian: overproduction of urine, forward displacement of the eyes, and skull defects. May exhibit optic nerve swelling and an inability to move the eyes, usually before age 10
Heerfordt: uveitis, fever, and parotid gland swelling; now recognized as a manifestation of sarcoidosis
Hepato-lenticular Degeneration (Wilson): abnormality of copper metabolism associated with progressive degeneration of the liver and lentate nucleus, mental retardation, and a brownish ring (Kayser-Fleisher) composed of copper at the periphery of the cornea.
Horner: sympathetic nerve paralysis with constricted pupil, droopy eyelid, reduced facial sweating
Hunter: metabolic dysfunction characterized by skeletal abnormalities, mental retardation and cloudy corneas, all after age 30
Hurler (gargoylism): characterized by dwarfism with short spinal column, short fingers, depression of the bridge of the nose, heavy, stiffness of joints, cloudiness of cornea, retinal degeneration, heart problems, and mental retardation
Laurence-Moon-Biedl: inherited disturbance of the pituitary gland characterized by obesity, underdeveloped sex organs, mental retardation, extra fingers and toes, and retinal degeneration
Leber: rapidly progressive optic nerve degeneration affecting both eyes occurring about the age of 20 years
Lindau-von Hippel: characterized by tumors of the retina, central nervous system and visceral organs. Primary eye findings are blood-filled retinal tumors bed by large, vessels
Marcus Gunn: droopy eyelid that opens wide when chewing, sucking or moving mouth to the opposite side of body
Marfan's: connective tissue disease with spidery fingers and toes, relaxed ligaments, spine and joint deformities, congenital heart disease, and dislocated lenses. May be myopic and have large corneas, cataracts, and droopy eyelids, strabismus, or incomplete choroidal formation.
Niemann-Pick: fatty deposits accumulate in organs, nerve tissue, and eyes. Retinal changes may include cherry red spots or grayish haze
Orbital Apex: limitation of eye movement, bulging eye, and decreased corneal and eyelid sensation. Optic nerve involvement causes decreased vision and visual field loss
Osteogenesis Imperfecta (Van der Hoeve): bone fragility, blue sclera, and deafness
Parinaud Oculoglandular Conjunctivitis: conjunctival lesions surrounded by follicles
Parinaud's: decreased ability to move the eyes up or down, brainstem lesion near the vertical gaze center
Purtscher: multiple retinal white patches, cotton-wool spots, hemorrhages, and swelling of the retina following sever chest trauma that causes a sudden increase in venous blood pressure
Refsum: hereditary retinal degeneration, polyneuritis, deafness, and cerebellar signs
Reiter: arthritis, urethritis, conjunctivitis, or iritis
Riley-Day: nervous system disorder with reduced tear production, decreased corneal sensation, exotropia, myopia, excessive sweating
Sjogren: connective tissue disease with dry eyes, mouth and arthritis
Stargardt: degenerative disease of the macula occurring before puberty
Stevens-Johnson: severe conjunctival disease, eye lid scarring, dry eyes, and closure of the tear ducts
Stickler's: progressive connective tissue disease that causes joint problems Mid-facial flattening, cleft palate, hearing loss, myopia, cataracts and vitreoretinal degeneration
Sturge-Weber-Dimitri: reddish pigmentation on side of face, often associated with glaucoma, large eye
Synechiae: adhesion between the iris and adjacent structures
Tay-Sachs: opaque central retina due to lipid-filled ganglion cells, fovea appears as a cherry red spot, pale optic nerve, leads to blindness and death
Vogt-Speilmeyer: diffuse nervous system disease, macular lesions, and optic nerve degeneration
Weber: paralysis of the oculomotor nerve (N III) on the same side as the lesion and spastic hemiplegia on the side opposite the lesion with increased reflexes and loss of superficial reflexes

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T

TALBOT

unit of light equal to one lumen-second

TANGENT SCREEN

a large black or gray curtain supported by a framework on which the normal central field and blind spot have been lightly outlined. This instrument is used for measuring the central field of vision

TARSORRHAPHY

operation in which the lids are sutured together

TARSUS

the framework of connective tissue which gives shape to the eyelid

TELESCOPIC GLASSES

magnifying spectacles founded on the principles of a telescope; occasionally prescribed for improving very poor vision which cannot be helped by ordinary glasses

TEMPORAL ARTERITIS

giant cell arteritis

TENSION, INTRAOCULAR

test by means of which the amount of fluid forced from the eye by a constant pressure during a constant period is determined

TONOMETER

instrument for measuring ocular tension

Applanation: instrument used to measure intraocular pressure in which the globe is not indented
Schiotz: indentation type of instrument

TOXIC AMPLYOPIA

poor vision secondary to poisoning of any kind

TOXOPLASMOSIS

severe intraocular infection caused by the presence of toxoplasma gondu organisms; transmitted through the feces of domestic animals such as cats or birds or ingestion of raw meat containing organism

TRACHOMA

a form of infectious kerato-conjunctivitis caused by a specific virus which in the chronic form produces severe scarring of the eyelids and cornea

TRICHIASIS

condition in which eye lashes turn inward toward the eyeball

TRITANOPIA

form of dichromatism in which there are but two cone pigments present and there is a complete insensitivity to blue

TROPIA

a root word denoting a manifest deviation from normal of the axis of the eyes (strabismus) used with a prefix to denote the type (hetertropia, estropia, exotropia)

TUNNEL VISION (GUN-BARREL, TUBULAR)

contraction of the visual field to such an extent that only a small area of central visual acuity remains, thus giving the affected individual the impression of looking through a tunnel

ULCER OF THE CORNEA

a loss of substance of the surface of the cornea secondary to infection

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U

UVEA: the iris, ciliary body, and choroid
UVEAL TRACT: entire vascular coat of the eyeball. It consists of the iris, ciliary body, and choroid.
UVEITIS: inflammation of the iris, ciliary body, and choroid

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V

VASCULAR

of or pertaining to the blood vessels

VERNAL CONJUNCTIVITIES

inflammation of the conjunctiva presumably due to allergy and characterized by giant papillary hypertrophy of the conjunctiva

VISION

the art of seeing; sight

Binocular: using both eyes synchronously, without diplopia
Color: ability to distinguish subjectively a large variety of wavelengths of light in the visible spectrum
Photopic: vision in bright illumination
Scotopic: vision in dim illumination or vision following the biochemical or neurologic changes occurring in dark adaptation

VISUAL ACUITY

central or direct vision for distance and near; the vision record which a person attains on a chart, usually the Snellen Chart

VISUAL ANGLE

angle that an object or details subtends at the point of observation; usually measured in minutes of arc

VISUAL FIELD

full extent of the area visible to an eye when the head and eyes are kept fixed

VISUAL LINE

that line which connects a point in space with the fovea centralis

VISUAL PURPLE

a pigmentary substance in the retina reacting to light in such a manner as to produce nervous impulses which are interpreted finally as visual sensation

VITREOUS

transparent, colorless mass of soft gelatinous material filling the eyeball behind the lens

VITREOUS OPACITIES

See "FLOATERS"

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X

XANTHELASMA FLAT: sharply circumscribed deposits of lipid in the eyelids, sometimes associated with hypercholesterolemia

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Y

YELLOW SPOT: term applied to macula lutea

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Z

ZONULE OF ZINN: the suspensory ligament of the crystalline lens

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