Upper and lower muscular folds of skin that move to cover and uncover the eyeball.
Transparent front layer of the eye that covers the iris and the pupil. Provides most of the eye's optical power.
Flat, circular membrane forming the colored portion of the eye, with an adjustable circular opening, the pupil, in the center.
Dark, circular opening in the center of the iris which varies in size to regular the amount of light reaching the retina.
Transparent, biconvex tissue that helps bring rays of light to focus on the retina.
Small depression in the retina where visual acuity is highest.
Irregularly oval, yellow-pigmented area on the central retina that contains color-sensitive rods and the region sharpest vision acuity.
Cell layers, sensitive to light, receive images produced by the lens and triggers nerve impulses that pass via the optic nerve to the brain.
Pair or cranial nerves, consisting of sensory fibers that transmit sight impulses to the brain.
Transparent, gelatinous mass which fills two-thirds of the eye between the lens and the retina.