Injection therapy may hold more promise that previously thought for curing blindness. Researchers are closer to finding a way to restore sight for patients blinded by certain types of macular degeneration.

"Macular degeneration has been a condition that we haven't been able to do a lot for. For many years, we had no treatment. We had to tell people, go home, use more light, use magnification, but we really can't help you," said Dr. Sanford Feldman of Scripps Health.

Soon that could change. A team of researchers at University of California Berkeley found a temporary return of vision to blind mice by injecting an ammonium chemical.

The chemical increases the sensitivity of light to the eyes, which allowed the mice to see.

"It's the first sign that we can actually inject something into the eye that will reverse the damage done to cell called photo receptors which cause blindness," said Dr. Sanford.

The ability to inject chemicals to cure blindness is a greater step than previous research that has been more permanent, like gene therapy.

"The chemicals are gone when they're gone. So, if it doesn't work or it causes problems, the chemical is out of the eye and essentially you've turned off the treatment. You don't have to worry about what it might be doing from that point on," said Dr. Sanford.

With more than 3 million people affected from visual impairments, this step could be a way for doctors to finally help the blind patients they never could before.