Eye Structure

Fibrous Tunic

Outermost layer; composed of the sclera and cornea.

Cornea

Clear anterior portion; allows light to enter and provides some focus.

Sclera

The "white" of the eye; made of connective tissue for muscle attachment and shape.

Vascular Tunic

The middle layer of the eye; provides the blood supply.

Choroid

Posterior portion of the vascular tunic; black in color to absorb excess light.

Ciliary Body

Smooth muscle that holds the lens; adjusts lens thickness for focus and produces aqueous humor.

Iris

The colorful smooth muscle; controls the amount of light entering the eye by adjusting pupil size.

Lens

A clear mass that focuses the image onto the retina.

Nervous Tunic

The innermost layer; contains nerve receptors.

Retina

Thin nerve layer with photoreceptors that merge to form the optic nerve.

Aqueous Humor

Watery fluid in the anterior chamber; provides nutrients and maintains shape

Conjunctiva

Clear mucous membrane; provides moisture to decrease friction.

Vitreous Humor

Jello-like fluid in the posterior chamber; holds the retina in position and maintains shape.

Superior Rectus

Moves the eye Upward.

Inferior Rectus

Moves the eye downward

Lateral Rectus

Moves the eye Outward (away from the midline).

Medial Rectus

Moves the eye Inward (toward the midline).

Superior Oblique

Moves the eye Downward and Outward.

Inferior Oblique

Moves the eye Upward and Outward