As Michael Kaleko kept running into people who were getting older and having more vision problems, he realized he could do something about it.

Early last year, he and two other scientists founded Advanced Vision Therapies Inc. of Rockville, which is developing a technology to treat back-of-the-eye diseases through gene therapy.

"If we could do something to prolong people's vision, I personally would consider that a lifetime achievement," Kaleko said.

Eye-related diseases worsen as people age, with some leading to blindness. One of the most serious and debilitating eye diseases is age-related macular degeneration, or AMD. Caused by the hardening of the arteries that nourish the retina, it is the most common cause of vision loss in the United States in those 50 and older.

As one gets older, the back of the eye wears out to some extent, creating a loss of vision, and for some patients, new blood vessels that grow in the retina are defective. This is known as dry AMD. When these fragile blood vessels leak and bleed (wet AMD), however, it can rapidly lead to blindness, Kaleko said. About 10 percent of those who suffer from AMD have wet AMD.

AVT is developing a gene transfer vector, a vehicle holding a specific gene, that would be injected into the edge of the retina. The vector is supposed to bind to the cells in that area, releasing a gene. That gene is supposed to allow the cells to produce therapeutic proteins that would bathe the retina, knock out defective blood vessels and prevent others from cropping up, Kaleko said. A second AVT product would treat dry AMD and other eye diseases by keeping alive photo receptors, which enable people to see light.

Some of the treatments now used to slow vision loss, such as lasers or repeated injections to the back of the eye -- some every four to six weeks -- are either injurious or counterproductive, he said. Kaleko said his company's treatment "will be easier to take and be more efficacious in the long run."

AVT hopes to begin clinical trials in early 2006, pending Food and Drug Administration approval. The company is also seeking venture capital.

Michael Kaleko, center, Sheila Connelly and Tianci Luo founded Advanced Vision Therapies Inc. of Rockville, a biotechnology company that seeks to treat eye diseases with gene therapy.