Lens (anatomy)

The lens or crystalline lens is a transparent, biconvex structure in the eye that, along with the cornea, helps to refract light to focus on the retina. Its function is thus similar to a man-made optical lens. Also known as the aquula (Latin, a little stream, dim. of aqua, water).

In humans, the refractive power of the lens in its natural environment is approximately 15 dioptres, roughly one-fourth of the eye's total power.