Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber and provides most of an eye's optical power http://www.eyeglossary.net/#C. Together with the lens, the cornea refracts light and consequently helps the eye to focus. The cornea gives a larger contribution to the total refraction than the lens, but whereas the curvature of the lens can be adjusted to "tune" the focus, the curvature of the cornea is fixed. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
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~ ~ ~ ~ ~ ~ ~ ~ ~ ~ The cornea has sensitive nerve endings; touch of the cornea causes an involuntary reflex to close the eyelid. Because transparency is of prime importance, the cornea does not have blood vessels; it receives nutrients via diffusion from the tear fluid at the outside and the aqueous humour at the inside. In humans, the cornea has a diameter of about 12 mm and a thickness of 0.5 - 0.7 mm in the center and 1.0 - 1.2 mm at the periphery. ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Medical terms related to the cornea often start with "kerat-". ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
Eye: : This article refers to the sight organ. See Eye (disambiguation) for other usages.... Iris: :For uses as an abbreviation, see IRIS... Pupil: The term pupil can also mean student. See also: exit pupil... | ~ Table of Content ~
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~ Related Subjects ~Diffusion (1) - Aqueous humour (1) - Eyelid (1) - Blood vessel (1) - Student (1) - Exit pupil (1) - Human (1) - Mm (1) - Reflex (1) - Pupil (1) - Lens (1) - Eye (1) - Iris (1) - Curvature (1) - Nerve (1) -~ Community ~
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