Color blindness as part of the retinal damage caused by diabetes. Vitamin A deficiency may also cause color blindness. Some subtle forms of color blindness may be associated with chronic solvent-induced encephalopathy (CSE), caused by long-time exposure to solvent vapors. Red–green color blindness can be caused by ethambutol, a drug used in the treatment of tuberculosis. The typical human retina contains two kinds of light cells: the rod cells (active in low light) and the cone cells (active in normal daylight). Normally, there are three kinds of cone cells, each containing a different pigment, which are activated when the pigments absorb light.
Retina in "Retina der Wirbelthiere" ("The Retina of Vertebrates"). George Wald, Haldan Keffer Hartline, and Ragnar Granit won the 1967 Nobel Prize in Physiology or Medicine for their scientific research on the retina. A recent University of Pennsylvania study calculated that the approximate bandwidth of human retinas is 8.75 megabits per second, whereas a guinea pig's retinal transfer rate is 875 kilobits per second. MacLaren & Pearson and colleagues at University College London and Moorfields Eye Hospital in London, in 2006, showed that photoreceptor cells could be transplanted successfully in the mouse retina if donor cells were at a critical developmental