The human eye has been called the most complex organ in our body. It’s amazing that something so small can have so many working parts. But when you consider how difficult the task of providing vision really is, perhaps it’s no wonder after all.
(Mouse over the words in the eye anatomy illustration below for their definitions.)
How The Eye Works
In a number of ways, the human eye works much like a digital camera:
Light is focused primarily by the cornea — the clear front surface of the eye, which acts like a camera lens.
The iris of the eye functions like the diaphragm of a camera, controlling the amount of light reaching the back of the eye by automatically adjusting the size of the pupil (aperture).
The eye’s crystalline lens is located directly behind the pupil and further focuses light. Through a process called accommodation, this lens helps the eye automatically focus on near and approaching objects, like an autofocus camera lens.
Light focused by the cornea and crystalline lens (and limited by the iris and pupil) then reaches the retina — the light-sensitive inner lining of the back of the eye. The retina acts like an electronic image sensor of a digital camera, converting optical images into electronic signals. The optic nerve then transmits these signals to the visual cortex — the part of the brain that controls our sense of sight.