Eye Anatomy

Conjunctiva

Lines inside of eyelids and connects to front of eye; produces mucus

Lacrimal apparatus/gland

Produces tears which protect, moisten, and lubricate the eys

Extrinsic eye muscles

Responsible for rotating the eyeball

Sclera

Makes up most of the fibrous layer; white

Cornea

Clear anterior portion of fibrous layer

Choroid

Posterior portion of vascular layer; nutrient-rich

Ciliary body

A circular muscle that relaxes or tightens to change the shape of the lens.

Iris

Circular and radial muscles that adjust the size of the pupil

Optic disc

Where the optic nerve leaves the eye; aka "blind spot"

Rods

photoreceptive cells that are adjusted for dim light; perceive gray tones

Cones

photoreceptive cells that are adjusted for bright light; perceive colors

Fovea centralis

Part of retina with only cones; greatest visual acuity here

Cataracts

When the lens becomes hard and opaque

Aqueous humor

Between cornea and lens; supplies nutrients and maintains pressure

vitreous humor

Gel-like, between lens and posterior; maintains eye shape

Bipolar neurons and ganglion cells

Provide a pathway for visual information from photoreceptors to brain

Eyelashes

Located on the margin of the eyelids. Prevent foreign substances from entering the eye.

Macula

Area surrounding the fovea near the center of the retina in the eye, which is the region of keenest vision.

Glaucoma

a condition of increased pressure within the eyeball, causing gradual loss of sight.

Myopia

Difficulty focusing distant objects (nearsightedness)

Hyperopia

Difficulty focusing nearby objects (farsightedness)

emmetropia

normal condition of the eye.

normal, perfect vision

Rhodopsin

Light sensitive molecule/ pigment found in the rods and cones of the retina

Suspensory Ligaments

Long, thin fibers which connect the crystalline lens to the ring of ciliary muscles.

astigmatism

defective curvature of the cornea or lens of the eye

lacrimal fluid

tears; maintains moisture on the anterior surface of the eyeball

nasolacrimal duct

empties lacrimal fluid into the nasal cavity

fibrous tunic

sclera and cornea (outermost layer)

vascular tunic

choroid, ciliary body and lens, iris (middle layer)

Sensory tunic

Retina (Innermost layer)