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.
Kodak Retina Reflex is coupled to the aperture ring - moving the shutter ring automatically moves the aperture ring, so that the same exposure value is maintained. In other words, when in use, the camera is normally locked into one EV setting until the aperture release tab is pressed. Needless to say this can be confusing to those unfamiliar with the camera. All the Retina Reflex cameras are remarkably complex instruments and quite heavy for their size. The Retina Reflex originally sold for $215 USD (app. $1,820 USD in 2014). Approximately 65,000 were made. The Retina Reflex can be fitted with four different