Eye Anatomy

The Human Eye Labeled:

The eye is an incredibly intricate body part that is often overlooked for its detailed structure and function. Pictured here is a colored and labeled photo of the human eye, which clearly displays its basic makeup and vital parts. Additionally, included below are brief summaries of each labeled part's location, composition, and function (there is also a smaller section further below containing information about a few other key ocular parts/concepts not pictured).

Lastly, toward the very bottom of the page are links to a few recommended YouTube videos that further detail the overall anatomical structure and function of the eye.

Anterior Chamber

Location: outer front of the eye

Composition: aqueous humor (watery, gel-like substance)

Function: holds aqueous humor

Aqueous Humor

Location: outer front of the eye

Composition: water, amino acids, and sodium (98-99% water)

Function: Helps maintain the eye's shape

Choroid

Location: lines the middle layer of the outer wall of the eye

Composition: tissue and blood vessels

Function: supplies nutrients and regulates temperature

Ciliary Body

Location: inner front of the eye

Composition: smooth muscle fibers (a.k.a ciliary muscles)

Function: helps the eye to focus and produces the aqueous humor solution

Cornea

Location: outer front of the eye

Composition: numerous layers of tissue

Function: protects the eye from outside debris/harmful light and helps direct/focus the amount of light that enters into the eye

Fovea

Location: inner back of the eye

Composition: mostly cone cells

Function: responsible for providing sharp (well-defined) vision

Hyaloid Canal

Location: runs through the center of the eye from the lens to the optic nerve

Composition: collagen

Function: supplies blood to the lens during early development (afterwards becomes filled with lymph)

Iris

Location: outer front of the eye

Composition: two layers of smooth muscle (the amount of pigment present determines eye color)

Function: helps regulate the amount of light that can enter into the retina by controlling the pupil

Lens

Location: inner front of the eye

Composition: tissue with high protein concentration

Function: changes its shape to help focus, adjust, and clarify visual objects at varying distances for the retina

Macula

Location: outer back of the eye

Composition: photoreceptor cells (i.e., rods & cones)

Function: responsible for central vision

Optic Disc

Location: outer back of the eye

Composition: combination of numerous tissues

Function: transfers signals between photoreceptor cells and the optic nerve

Optic Nerve

Location: outer back of the eye

Composition: nerve fibers (axons of retinal ganglion cells)

Function: communicates visual signals to the brain

Posterior Chamber

Location: inner front of the eye

Composition: aqueous humor (watery, gel-like substance)

Function: holds aqueous humor

Pupil

Location: outer front of the eye

Composition: hole in the middle of the iris

Function: regulates the amount of light that can enter into the retina by changing its size (controlled by the iris)

Retina

Location: inner back of the eye

Composition: neural, glial, and photoreceptor cellular layers

Function: converting light energy into electrical energy

Retinal Blood Vessels

Location: emerge from the optic nerve (outer back of the eye)

Composition: blood/nutrients

Function: nourishes the retina

Sclera

Location: surrounds the outer part of the eye (from the cornea to the optic nerve)

Composition: numerous layers of tissue (same as cornea) and gives the eye its white color

Function: helps maintain the eye's shape and prevent injuries

Suspensory Ligaments

Location: inner front of the eye

Composition: connective tissue

Function: holds the lens in place and connects it to the ciliary body

Uvea

Location: throughout the outer wall of the eye

Composition: comprised of the choroid, iris, and ciliary body

Function: varies based on its individual parts

Vitreous Body/Humor

Location: middle of the eye

Composition: water, glucose, and charged particles (98-99% water)

Function: helps maintain the eye's shape

Other Key Parts/Concepts of the Eye (Not Labeled):

Axons of the Eye

Location: inner & outer back of the eye

Composition: retinal ganglion cells

Function: sends electrical nerve impulses from eye to brain

Eyelashes & Eyelids

Location: surrounding the outer front eye

Composition: small hair follicles (eyelashes) and skin/soft tissue (eyelids)

Function: tear lubrication (eyelids) and debris protection (eyelashes/eyelids)

Orbit & Extraocular Muscles

Location: surrounding the inner part of the eye

Composition: bony structure (orbit) and skeletal muscle (extraocular muscles)

Function: structural support/protection (orbit) and facilitates movement (extraocular muscles)

Photoreceptors (Rods & Cones)

Location: inner back of the eye

Composition: cellular material for rods and cones

Function: helps with night vision (rods) and helps with color and daytime vision (cones)

Retinal Ganglion Cells

Location: inner back of the eye

Composition: axons and dendrites

Function: helps with overall communication between the eye and the brain