Retinal detachment is movement of the transparent sensory part of the retina away from the outer pigmented layer of the retina. In other words, the portion of the retina pulls away from the outer wall of the eyeball.

There are three layers to the eyeball: The outermost layer is the tough, white sclera; the sclera is lined by the choroid, a thin membrane that supplies nutrients to part of the retina; and the innermost layer is the retina itself--the light-sensitive membrane that receives images through the pupil and transmits them to the brain. The retina is also made up of several layers. One layer contains the photoreceptors--the rods and cones--that send the visual message to the brain. Between this photoreceptor layer (also called the sensory layer) and the choroid is the pigmented epithelium.

Filling the inner space of the eyeball itself is the vitreous, a clear...