The Human Eye: Structures and Function

Cornea

Clear, convex covering that protects the front of the eye and helps to focus incoming light.

Aqueous Humor

Clear, watery fluid that delivers oxygen and nutrients while maintaining constant pressure inside the eye.

Iris

Colored part of the eye that dilates or constricts to control the amount of light entering the eye.

Pupil

Hole in the center of the iris that allows light to enter the eye; size depends on brightness.

Lens

Focuses light onto the retina; changes shape using ciliary muscles to focus on nearby and distant objects.

Vitreous Humor

Clear, jelly-like substance that helps the eye maintain its shape and further focuses light onto the retina.

Retina

Thin, light-sensitive tissue lining the back of the eye that receives and processes light signals.

Optic Nerve

Bundle of nerve fibers that carries visual information from the eye to the brain.

Path of Light Through the Eye

Cornea -> Aqueous Humor -> Pupil -> Lens -> Vitreous Humor -> Retina