My lesson

sclera

the white outer layer of the eyeball. At the front of the eye it is continuous with the cornea.

cornea

The cornea is the eye's outermost layer. It is the clear, domeshaped surface that covers the front of the eye. It plays an important role in focusing your vision.

lacrimal glands

The lacrimal glands are paired, almond-shaped exocrine glands, one for each eye, that secrete the aqueous layer of the tear film. They are situated in the upper lateral region of each orbit.

Iris

is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina.

pupil

The opening of the iris. The pupil may appear to open (dilate) and close (constrict), but it is really the iris that is the prime mover;

ciliary muscles

alters the curvature of the lens

aqueous humor

the clear fluid filling the space in the front of the eyeball between the lens and the cornea.

lens

By changing its shape, the lens changes the focal distance of the eye. It also works together with the cornea to refract, or bend, light.

vitreous humor

the transparent jellylike tissue filling the eyeball behind the len

retina

a layer at the back of the eyeball containing cells that are sensitive to light and that trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.

choroid

the pigmented vascular layer of the eyeball between the retina and the sclera.

macula

an oval yellowish area surrounding the fovea near the center of the retina in the eye, which is the region of keenest vision.

fovea

a small depression in the retina of the eye where visual acuity is highest. The center of the field of vision is focused in this region, where retinal cones are particularly concentrated.

optic disk

the raised disk on the retina at the point of entry of the optic nerve, lacking visual receptors and so creating a blind spot.

blind spot

corresponds to an area in the eye where the optic nerve enters the retina.

optic nerve

each of the second pair of cranial nerves, transmitting impulses to the brain from the retina at the back of the eye.