Mercy Eye Center

How the Eye Works

The eye is like a camera, with a lens to focus light and then record an image on the retina which is in the back of the eye. The eye is connected to the brain by an optic nerve.



The major structures of the eye from front to back are the cornea, iris, lens, vitreous and retina. The cornea is the clear transparent membrane directly in front of the iris. The anterior chamber behind the cornea and in front of the iris is filled with aqueous, a fluid which provides oxygen and nutrients for intraocular structures. The iris, which is immediately in front of the crystalline (eye) lens, is the structure of the eye which controls the size of our pupil, dilating in low light conditions and constricting in bright. As light passes through the pupil, it enters the lens which bends the light to foucs images through the vitreous onto the retina. The retina then transmits the image via the optic nerve through the visual pathway to the visual cortexof the brain.