Genentech's Lucentis helps prevent vision loss due to diabetic macular edema, a phase three clinical trial sponsored by the National Eye Institute found. The trial, which included 691 patients or 854 eyes (as not everyone had both eyes treated), found that 3 to 4 percent of Lucentis-treated eyes had visual loss after the one year while 13 percent of those treated with lasers did, reports the New York Times.