Eyes Flashcards
Accommodation
Accommodation: adjustment of the eye for various distances through modification of the lens curvature.
Amsler grid
Amsler grid: a set of charts with various geometric shapes in black and white, used for detecting defects of the central visual field.
Anisocoria
Anisocoria: inequality of the diameter of the pupils; may be normal or congenital. Often normal if inequality is within 1mm.
Aphakia
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.
Aqueous humor
Aqueous 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.
Astigmatism
Astigmatism: 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
Cataracts: opacity of the lens; most commonly resulting from denaturation of the lens protein caused by aging.
Chalazion
Chalazion: small, hard tumor analogous to sebaceous cyst developing on the eye lids, formed by the distention of a meibomian gland with secretion.
Choroid
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.
Ciliary body
Ciliary 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
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
Confrontation: a test for estimating peripheral vision.
Conjunctiva
Conjunctiva: the mucous membrane investing the anterior surface of the eyeball and the posterior surface of the lids.
Conjunctivitis
Conjunctivitis: inflammation of the conjunctiva caused by infectious agents or by allergies; commonly called pinkeye.
Cornea
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.
Corneal arcus
Corneal 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
Cotton wool spot: an ill-defined yellow areas due to infarction of the nerve layer of the retina.
Depth perception
Depth perception: perception of spatial relationships; three dimensional perception. The visual ability to judge depth or distance.
Diabetic retinopathy (background)
Diabetic retinopathy (background): a condition characterized by dot hemorrhages or microaneurysms and the presence of hard and soft exudates.
Diabetic retinopathy (proliferative)
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.