Transplanting light-sensitive photoreceptor cells into mice with night blindness resulted in improved night vision. Night blindness means seeing poorly in the darkness, but seeing normally when there is enough light. In this groundbreaking research, scientists injected light-sensitive photoreceptor cells into night-blind mice’s eyes. After this treatment, the animals were able to see well enough to navigate a water maze and swim toward a visual cue in dimly lit conditions. Controls who did not receive the treatment were unable to efficiently navigate the maze.
Night blindness can have many causes, including retinitis pigmentosa, macular degeneration, rod-cone dystrophy, cataracts, vitamin A deficiency, congenital night vision disorder, diabetes, or severe short-sightedness (myopia). The mice used in the experiment lacked rod function, and were considered to be a model of congenital stationary night blindness.
Rod-photoreceptor cells are particularly important for seeing in the dark. The cells that the scientists transplanted were immature rod-photoreceptor cells. After four to six weeks, as many as 15% of the transplanted cells had formed the necessary connections and started transmitting visual information to the animals’ brain.
The researchers hope to experiment in the future with photoreceptors that come from embryonic stem cells. They already have cells, but need to find a way to transplant them efficiently. Human trials may be a while off. Transplanting rod receptors has so far been easier than transplanting cone receptors; both are needed for good vision in humans.
Night blindness should not be self-diagnosed. Symptoms include trouble driving at night, reduced vision in low lighting condition, and taking more time to adjust to the dark. A doctor should be consulted when an individual has difficulty seeing in the dark.
Note: Night vision may be improved using specific nutritional supplementation such as Bilberry, Lutein, Ginkgo Biloba, Zeaxanthin, Vitamin A, and other vitamins and minerals. See more information on night blindness.
Sources:
“Restoration of vision after transplantation of photoreceptors” by R. A. Pearson et al. Nature 485, 99–103 (03 May 2012) doi:10.1038/nature10997
“‘Blind’ mice eyesight treated with transplanted cells” BBC News Health. April 18, 2012.
