RALEIGH, N.C. — New research points to a single gene that may be at the heart of nearly half of all macular degeneration cases.

The macula is the central part of the eye's retina that provides central vision. When that area deteriorates with age, you see a growing dark spot. There is no cure, just treatments that slow its progression.

Duke's Dr. Margaret Paricak-Vance, along with researchers at Vanderbilt, zeroed in on a gene, which may pave the way for early detection and better treatments.

"It's a very exciting time and hopefully, you know, we'll be able to do something positive for the patients, which is what it's all about," Vance said.

The discovery could lead to early detection and better treatment. Macular degeneration already affects 15 million Americans. As baby boomers reach retirement age, that number could double.

Sidney Journigan suffers from macular degeneration. He does not expect a cure in his lifetime, but he hopes one will come in time to help those who inherit his genetic makeup.

"I have sons and grandsons and I hope that this will benefit them in the long run," he said.

Duke researchers said the next step is to search for the gene in as many patients as possible to see how widespread it is.