"An experimental drug is showing promise against an untreatable eye disease that blinds older adults  and intriguingly it seems to work in patients who carry a particular gene flaw that fuels the damage to their vision. Agerelated macular degeneration or AMD is the leading cause of vision loss among seniors gradually eroding crucial central vision. There are different forms but more than  million people worldwide and a million in the U.S. have an advanced type of socalled dry macular degeneration that has no treatment. First patients may notice blurriness when they look straight ahead. Eventually many develop blank spots becoming legally blind.  These are seniors who are entering their golden years and now theyve lost the ability to read watch television see their loved ones said Dr. Rahul Khurana a retina specialist and spokesman for the American Academy of Ophthalmology. The experimental drug lampalizumab aims to slow the destruction of lightsensing cells in the retina creeping lesions that characterize the stage of dry AMD called geographic atrophy. When those cells die they cant grow back  the vision loss is irreversible. What the research found In an month study of  patients monthly eye injections of the drug modestly slowed worsening of the disease when compared with patients given dummy shots. Whats exciting for scientists came next when researchers from drugmaker Genentech Inc. took a closer look at exactly who was being helped. It turns out that nearly  in  of the studys participants carry a gene variation that makes part of the immune system go awry  a genetic flaw already known to increase the risk of getting macular degeneration in the first place. Those are the only patients who appeared to benefit from the drug they had  per cent less eye damage than the untreated patients the Genentech team reported Wednesday in the journal Science Translational Medicine. While the study is too small to prove if lampalizumab really helps maintain vision thats a bigger difference than the overall results suggested. Why would an immunerelated gene affect aging eyes One arm of the immune system the complement pathway helps fight infections by attracting immune cells to attack bacteria. Normally theres a barrier that keeps such cells away from the retina. But that barrier can break down with age opening sensitive eye cells to harm from the spillover explained Genentech immunologist Menno van Lookeren Campagne. Now for the gene connection Previous studies have linked macular degeneration to gene variations that remove some of that pathways natural brakes so it can become too active. The hypothesis Genentechs drug lampalizumab essentially offers a backup method for tamping down the immune reaction. An antibody it works by inhibiting a particular enzyme named factor D that helps power the immune pathway. We try to reinsert the braking ability said study lead author Brian Yaspan a Genentech senior scientist. Whats next Wednesdays study detected no safety concerns clearing the way for Genentech and its parent company Roche to open two largescale studies that aim to prove if the drug works. Results are expected later this year. The current research sheds light on how that longsuspected immune culprit might be working and is the first suggestion that there may be a treatment for geographic atrophy coming up in the future said National Eye Institute retina specialist Dr. Wai Wong who wasnt involved in the study. Its a very very exciting study said Khurana the ophthalmologist associations spokesman who also wasnt part of the research. From the basic science perspective it makes a lot of sense. Health advice for now Macular degeneration tends to occur after age  but it sometimes strikes earlier. According to the National Eye Institute its less common in people who exercise regularly avoid smoking and eat a diet high in green leafy vegetables and fish. Symptoms often arent noticeable early on. But several eye tests can detect signs of macular degeneration including a dilated eye exam and a tool called an Amsler grid with straight lines that may look wavy if the macula the centre of the retina is harmed. Macular degeneration patients often are advised to take certain vitamin combinations that may help stave off advanced disease. And its important for patients to know what type they have. While theres no treatment for the advanced dry form the wet form occurs when leaky blood vessels grow under the retina  and there are several therapies that can help those patients preserve vision."