[L. (tela) cornea, horny (web)]
The transparent anterior portion of the sclera, about one sixth of its surface. It is anterior to the aqueous humor, the iris, pupil, and lens of the eye. The cornea is the first part of the eye that refracts light. It is composed of five layers: an epithelial layer, Bowman's membrane (anterior limiting membrane), the substantia propria corneae, vitreous membrane, and a layer of endothelium. Beyond the edge of the cornea is the sclera (the white of the eye). The cornea has no blood vessels. Instead it derives nourishment from the tear film (in front) and the aqueous humor (behind).
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