Photoreceptors in the retina enable us to see in dim light (rods) and color (cones). In 2009, University of Washington researchers cured red-green color blindness in adult male squirrel monkeys, a species in which all males are naturally red. This is similar to red-green color blindness in humans, where they can distinguish blue from yellow and green, but struggle with differentiating red from green.
An exception is the howler monkey, which has routine trichromatic vision, similar to Old World monkeys and humans. Gene Therapy Here is one of our squirrel monkeys, Dalton, who was treated for red-green color blindness enjoying a feast of colored fruits and vegetables. The image on the left was digitally altered to simulate what the scene would look like to a person (or monkey) with red.
Female squirrel monkeys can see in color, but male monkeys are typically red. Scientists have used gene therapy to give full colour vision to adult squirrel monkeys that had been colour-blind since birth, opening up a world of formerly invisible reds and oranges, right in. Discover the fascinating world of monkey color perception and find out if these animals are truly colorblind.
Explore the latest research and understanding of how monkeys see the world through their eyes. How do researchers determine if a monkey can see color? Can monkeys with dichromatic vision distinguish between red and green? Does age affect color vision in monkeys? How does color blindness in humans compare to dichromatic vision in monkeys? What is the role of genetics in determining color vision in monkeys? Of course, a monkey can't tell you that the grass is green and a rose is red.
So to evaluate the monkeys' color vision, the Neitzes developed a computerized, touch-screen version of the test used to screen for color-blindness in humans, with shapes made of colored dots in a field of gray ones. To a colour blind monkey, this simply looks like the number '57'. Andre Dib / shutterstock Benefits of blindness But colour blind vision might actually be an advantage in some situations.
CURING COLOR BLINDNESS IN NONHUMAN PRIMATES Experiments using gene therapy in an attempt to cure congenital red-green color blindness in nonhuman primates were performed on adult squirrel monkeys (Saimiri sciureus). In this species, as in many other New World primates, there is a single opsin gene on the X chromosome, but there is allelic diversity at the locus (Jacobs 1984; Mollon et al. 1984.