Eyes Flashcards
accomodation
adjustment of the eye for various distances through modification of the lens curvature.
Amsley Grid
a set of charts with various geometric shapes in black and white, used for detecting defects of the central visual field.
Anisocoria
inequality of the diameter of the pupils; may be normal or congenital. Often normal if inequality is within 1mm
Aphakia
a condition in which part or all of the crystalline lens of the eye is absent, usually because of surgical removal for the treatment of cataracts.
Aqeous Humor
the watery transparent liquid containing trace albumin and small amount of salts produced by the iris, ciliary body, and cornea. It circulates through the anterior and posterior chambers of the eye.
Atigmatism
an 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
Choroid
the middle vascular tunic of the eye lying between the retina and the sclera. Dark brown vascular coat of the eye between the sclera and retina, extending from ora serrata to optic nerve. Consists of blood vessels united by connective tissue containing pigmented cells and is made up of five layers.
Ciliar body
the 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
the photosensitive, outward-directed, conical process of a 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 toward the periphery of the retina.
Confrontation
a test for estimating peripheral vision
Conjunctive
the 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
the clear, transparent anterior portion of the fibrous coat of the eye comprising about one sixth of its surface. It is the chief refractory structure of the eye.
Cornea arcus
opaque white ring about corneal periphery, seen in many individuals older than 60 years of age. This is due to deposit of lipids in the cornea or to hyaline degeneration. May indicate a lipid disorder, most commonly type II hyperlipidemia if present before the 40 years of age (if seen in younger people, it is called arcus juvenilis)
Cotton wool spot
an ill-defined yellow areas due to infarction of the nerve layer of the retina
Depth Perception
perception of spatial relationships; three dimensional perception. The visual ability to judge depth or distance.
Diabetic Retinopathy (background)
a condition characterized by dot hemorrhages or microaneurysms and the presence of hard and soft exudates
Diabetic Retinopathy (proliferative)
a condition characterized by 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
the 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