Eyes 1&2 Flashcards
Accommodation
Adjustment of the eye for various distances through modification of the lens curvature.
Amsler Grid
A set of charts with various geometric shapes in black and white, used for detecting defects on the central visual field.
Anisocoria
Inequality of the diameter of the pupils; may be normal or congenital. Often normal if inequality is within 1 mm.
Aphakia
Condition in which part or all of the crystalline lens of the eye is absent, usually due to surgical removal for cataract treatment.
Aqueous Humor
Watery transparent liquid containing trace albumin and small amounts of salts produced by the iris, ciliary body, and cornea. Circulates through the anterior and posterior chambers of the eye.
Astigmatism
Abnormal condition in which the light rays cannot be focused clearly in a point on the retina because of an irregular curvature of the cornea or lens.
Cataracts
Opacity of the lens; most commonly resulting from denaturation of the lens protein caused by aging.
Chalazion
Small, hard tumor analogous to sebaceous cyst developing on the eye lids, formed by the distention of a meibomian gland with secretion.
Choriod
Middle vascular tunic of eye lying between the retina and the sclera. Dark brown vascular coat of the eye between the sclera and retina, extending from ora serrate to optic nerve. Consists of blood vessels united by connective tissue containing pigmented cells and is made up of five layers.
Ciliary Body
Thickened part of the vascular tunic of the eye that joins the iris with the anterior portion of the choroid. Consist of three zones: ciliary disk, ciliary crown, and ciliary muscle.
Cones
Photosensitive, outward-directed, conical process of cone cell essential for sharp vision and color vision; cones are the only photoreceptor in the fovea centralis and become interspersed with increasing numbers of rods towards the periphery of the retina.
Confrontation
Test for estimating peripheral vision.
Conjunctiva
Mucous membrane investing the anterior surface of the eyeball and the posterior surface of the lids.
Conjunctivitis
Inflammation of the conjunctiva caused by infectious agents or by allergies; commonly called pinkeye.
Cornea
Clear, transparent anterior portion of the fibrous coat of the eye comprising about one sixth of its surface.
Corneal Arcus
Opaque white ring about the corneal periphery, seen in many individuals older than 60 years of age.
Cotton Wool Spot
Ill-defined yellow areas due to infarction of the nerve layer of the retina.
Depth Perception
Perception of spatial relationships; three dimensional perception. Visual ability to judge depth or distance.
Diabetic Retinopathy (Background)
Characterized by dot hemorrhages or microaneurysms and the presence of hard and soft exudates.
Diabetic Retinopathy (Proliferative)
Development of new vessels as a result of anoxic stimulation; vessels grow out of the retina toward the vitreous humor.
Diopter
Refractive power of the lens with focal distance of 1 meter, used as unit of measurement in refraction.
Diplopia
Condition in which a single object is perceived as two objects (double vision).
Drusen
Tiny yellow or white deposits in the retina of the eye or on the optic nerve head.
Ectropion
Eversion (outward rolling) of an edge or margin; as the edge of the eyelid.
Episcleritis
Inflammation of the superficial layers of the sclera located in front of the insertion of the rectus muscle.
Entropion
Inversion (inward rolling) of an edge or margin; especially the margin of the lower eyelid.
Exophthalmos
Increase in the volume of the orbital content, causing a protrusion of the globes forward. May be unilateral or bilateral. Most common cause of bilateral is Grave’s disease (thyroid disease), but when unilateral protrusion is noted a retro-orbital tumor must be suspected.
Farsightedness
Error of refraction in which, with accommodation completely relaxed, parallel rays come to focus behind the retina.
Glaucoma
Disease of optic nerve wherin the nerve cells die, producing increased cupping appearance of the optic nerve. An abnormal condition of elevated pressure within an eye resulting from obstruction of the outflow of aqueous humor.
Hemianopia
Blindness for half the field of vision in one or both eyes.
Hordeolum (sty)
Suppurative inflammation of the sebaceous gland of the eyelid.
Hyperopia (farsightedness)
Refractive error in which light rays entering the eye are focused behind the retina.
Hypertelorism
Eyes spaced widely apart.
Hyphema
Blood in the anterior chamber of the eye in front of the iris.
Iris
Colored contractile membrane suspended between the lens and cornea in the aqueous humor of the eye, separating the anterior and posterior chambers of the eyeball and perforated in the center by the pupil. By contraction and dilatation it regulates the entrance of light.
Iritis
Inflammation of the iris.
Legal Blindness
In the U.S., a person is usually considered legally blind when vision in the better eye, corrected by glasses, is 20/200 or less, or in the case of a constricted field of vision: 20 degrees or less in the better eye.
Macula (also known as fovea)
Site of central vision.
Mydriasis
Pupillary dilation.
Miosis
Abnormal contraction of pupils.
Myopia (nearsightedness)
Condition resulting from a refractive error in which light rays entering the eye are brought into focus in front of the retina.
Night Blindness
Decreased ability to see in reduced illumination. Seen in patients with impaired rod function; often associated with a deficiency of vitamin A.
Nystagmus
Involuntary rhythmic movements of the eye; the oscillations may be horizontal, vertical, rotary, or mixed.
Papilledema
Edema of the optic disc resulting in loss of definition of the disc margin; the cause often is increased intracranial pressure.
Peripheral Vision
Vision resulting from retinal stimulation beyond the macula.
Pinguecula
Harmless yellowish triangular nodule in the bulbar conjunctiva on either side of the iris that stops at the limbus.
Presbyopia
Hyperopia (farsightedness) and impaired near vision from loss of lens elasticity, generally developing during middle age.
Ptereygium
Triangular (patch like) thickening of the bulbar conjunctiva that grows slowly to the outer surface of the cornea, usually from the nasal side, and may cover a portion of the cornea.
Ptosis
Drooping of one or both upper eyelids.
Punctum
Tiny aperture (opening) in the margin of each eyelid that opens to the lacrimal duct.
Red Reflex
Response caused by light illuminating the retina.
Refraction
The act of determining the nature and degree of the refractive errors in the eye and correction of them by lenses.
Retina
Sensory network of the eye that transforms light impulses into electrical impulses, which are transmitted through the optic nerve.
Retinitis Pigmentosa
Chronic progressive disease, may occur in childhood, characterized by degeneration of the retinal neuroepithelium.
Retinoblastoma
Embryonic malignant glioma arising from the retina usually during the first two years of life. Initial diagnostic finding is usually a yellowish or white light reflex seen at the pupil (Cat’s eye reflex).
Rods
Photosensitive, outward-directed process of rhodopsin-containing rod cell in the external granular layer of the retina; many millions of such rods, together with cones, form the photoreceptive layer of rods and cones.
Sclera
Tough white fibrous tissue which covers the so-called white of the eye. Extends from the optic nerve to the cornea.
Scleritis
Superficial and deep inflammation of the sclera.
Strabismus
Condition in which both eyes do not focus on the same object simultaneously, however, either eye can focus independently.
Uveitis
Inflammation of the iris, ciliary body, and choroid, or the entire uvea.
Vitreous Body
Transparent jellylike substance that fills the cavity of the eyeball, enclosed by the hyaloid membrane; it is composed of a delicate network (vitreous stroma) enclosing in its meshes a watery fluid (vitreous humor).
Xanthelasma
Elevated plague commonly found on the nasal portion of the eyelid due to elevated cholesterol.
