lens

Pronunciation: lenz

Definition:

1. A transparent material with one or both surfaces having a concave or convex curve; acts on electromagnetic energy to cause convergence or divergence of light rays.
2. The transparent biconvex cellular refractive structure lying between the iris and the vitreous humor, consisting of a soft outer part (cortex) with a denser part (nucleus), and surrounded by a basement membrane (capsule); the anterior surface has a cuboidal epithelium, and at the equator the cells elongate to become lens fibers.

Synonym(s): crystalline lens

[L. a lentil]

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