In one study, researchers gave 150 mg daily to 19 glaucoma patients. After one month, vision in about half of the patients improved. In another experiment, doctors at the University Eye Clinic in Basel, Switzerland, gave 121.5 mg of magnesium daily to 10 glaucoma patients. After four weeks, blood flow and vision improved. Another nutrient, L-carnosine, may also protect against glaucoma, according to an animal study conducted by Russian researchers.
Night blindness is the inability of the eyes to quickly adjust to changes in light intensity.
For example, people whose eyes cannot quickly adjust to the darkness of a movie theater, or who are temporarily blinded by the glare of headlights at night, probably have night blindness. It is often a prelude to much more serious eye disorders, such as macular degeneration. Although statistics are not available, night blindness is often regarded as an early sign of vitamin A deficiency. Vitamin A forms part of the light-sensitive pigment rhodopsin, which receives and relays images to the brain. Although some research on vitamin A and night blindness dates back 80 years, recent scientific investigations have focused on malnourished people in developing nations.