R
REFRACTION
A change in the direction in which radiation is propagated, determined by variations in the propagation speed. |
RETINA
This extremely sensitive membrane, which lies fl at against the back inner wall of the eye, plays an essential role in the perception of light, colour, detail, shape and movement. (see EYE) |
RETINAL DETACHMENT
A separation of the retina from the pigmentary epithelium, resulting in a loss of vision in the area of the visual field that corresponds to the detached portion of the retina. |
RETINAL IMAGE
The image formed on the retina by the eye’s optical system. |
RODS
Photoreceptor cells that provide high sensitivity to low levels of lighting. |
|
|