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Med. Term. Review5
Eye Anatomy and Diseases
Question | Answer |
---|---|
cornea | Transparent layer of the eye after the sclera. Allows light to enter the eye. (most sensitive area of anterior surface of the eye). Limbus is the line between the sclera and cornea. |
iris | Circular structure of the eye with color |
pupil | Round opening in the iris that allows light rays to enter the eye |
conjunctiva | Delicate, transparent mucous membrane that covers the insides of the eyelids and the anterior surface of the eye. (produces a watery, clear mucus that traps foreign substances) |
sclera | Tough, fibrous connective tissue that forms a continuous outer layer of the eye. (white of the eye) muscles attach here |
uvea | (uveal tract) the iris, choroid, and ciliary body |
lens | Clear, flexible disk behind pupil. Suspensory ligaments attach here to the ciliary body. Thick/round - sees objects close by. Thin/flat - sees objects at a distance. |
choroid | Spongy membrane of blood vessels part of internal structure of the eye. (It is the middle layer between the sclera and retina.) |
ciliary body | Extension of the choroid. Holds lens in place behind iris. Contains muscles that contract and relax to change the lens to focus on light rays coming through the pupil. (produces aqueous humor) |
retina | Thin layer of tissue that lines the curved wall of the posterior cavity. (receives blood from the choroid which lies beneath). Also known as the fundus. |
optic disk | Bright, yellow-white circle with sharp edges in area of retina. Optic nerve enters the eye there. (cranial nerve II). There is a blind spot located here that receives no light. |
macula | Dark, yellow-orange area on retina |
fovea | A small depression in center of the macula (area of sharpest vision). |
rods | Sensitive in all levels of light and detect black and white only, not color. Located in retina. |
cones | Sensitive to color only. There are 3 types: red, green, or blue light. Located in macula of retina. |
optic chiasm | Crossing point where parts of one optic nerve join parts of the other optic nerve on the other side. |
hyperopia | Farsightedness. Light rays from a distant object focus correctly on the retina, but do not focus on near objects. *can see far away but not close. Close objects are blurry.* |
myopia | Nearsightedness. Light rays from a near object focus correctly on the retina but do not focus correctly on distant objects. *can see close (near) but not far away. Far objects are blurry.* |