Which part of the eye do we actually see out of? Like if we covered our pupils could we still see a bit with our irises and the whites? And whats the purpose of the iris?

Question

Which part of the eye do we actually see out of? Like if we covered our pupils could we still see a bit with our irises and the whites? And whats the purpose of the iris?

In: Biology

Answer 1

Light enters your eye from the pupil (after passing through the cornea, the transparent layer) which is “just” a hole. Then the light hits the retina, a special tissue with photoreceptors that transforms light in electrical impulses that the optical nerve can transfer to the brain, responsible of converting those impulses into the images you see.

If you cover the pupil, light in normal conditions can’t hit the retina so your brain won’t get any signal.

The iris is a membrane that controls the size of the pupil, allowing more or less light to enter the eye. Is made of two layers: the upper one, made by the stroma and a sphincter muscle responsible for contorlling the size of the pupil and a lower one, made by pigmented cells that blocks the light, so it can pass only through the pupil.