For the Color Blind, a Ray of Hope

ByABC News
September 16, 2009, 2:18 PM

Sept. 17 -- WEDNESDAY, Sept. 16 (HealthDay News) -- For color-blind people, new research in monkeys raises the possibility of a world in which they see colors like just about everyone else.

Scientists say they've used a form of gene therapy to eliminate red-green color blindness in monkeys, with no ill effects.

The treatment isn't for the squeamish, and there's no guarantee that it will work in humans. But study co-author Jay Neitz is optimistic.

"The great challenge of finding a way to cure color blindness is solved," said Neitz, a professor of ophthalmology at the University of Washington. "Now, the great problem is transforming this technology so it can be used on humans and be perfectly safe."

An estimated one in 12 men and one in 230 women have some form of inherited color blindness. They have trouble differentiating between some colors because receptors in their eyes lack the ability to perceive the full difference between them. Two percent of men have the most severe form of color blindness.

Color blindness can be inconvenient, leading people to pick clashing colors in clothes or be unable to read graphs and charts. In more severe cases, it can be dangerous. For example, people with red-green color blindness may see the two colors as gray and have trouble distinguishing red from green in traffic lights.

"Those people have a very different color experience than the rest of us," Neitz said. "The biggest challenge is jobs. That's where there's a real headache. You can't be a police officer, fireman, bus driver or pilot if you have red-green color blindness."

Nor, he said, can they be ophthalmologists. In fact, he said, medical students are occasionally disappointed to find that they can't be eye doctors.

There is no treatment for color blindness, although people can wear special glasses or contact lenses to better distinguish between colors.

In the new study, Neitz and colleagues inserted a missing gene into the eyes of red-green color-blind monkeys through an injection. The gene piggybacked on a virus that had been defanged so it no longer caused illness.