The backbone of the book consists of the 16 chapters on eye anatomy and physiology ... of scallops and shrimps use mirrors rather than lenses, that spiders are almost the only other creatures ...

Scientists have come up with scenarios through which the first eye-like structure, a light-sensitive ... at the back of the human eye. Over time a lens formed at the front of the eye.

Iris Coloured part of the eye that contains muscles ... by altering the thickness and curvature of the lens. Part Ciliary muscles Structure Muscles connected to the lens by suspensory ligaments.

The lens is a structure tucked deep inside the eye that helps us focus our vision on objects near and far. Natural lenses ...