"The effects of this drug on retinal health are phenomenal," Dr. Sylvia Smith, a retinal cell biologist and co-director of the Vision Discovery Institute at MCG's School of Medicine, said in a college news release.

For the study, she compared the retinas of diabetic mice treated with pentazocine and those that didn't receive the drug and found dramatic differences. The findings suggest that the drug and related compounds that bind with the sigma receptor in the eye may help treat the two leading causes of vision loss -- diabetic retinopathy and glaucoma.

The study was published in the September issue of the journal Investigative Ophthalmology & Visual Science.

Pentazocine's binding with sigma receptors didn't affect insulin levels in the diabetic mice.

"(The drug) does not solve that problem of diabetes; however, our findings do suggest that just because you are hyperglycemic does not mean you will have diabetic retinopathy," Smith said.