The CAPT is a multi-center, prospective, randomized clinical trial designed to assess the safety and effectiveness of low-intensity laser treatment in preventing vision loss among patients with large drusen in both eyes. A total of 1052 participants were enrolled in the study. Participants had one eye randomly assigned to laser treatment performed by a CAPT-certified ophthalmologist. The other eye was not treated. Both eyes were observed carefully for any changes for a period of five years. The effectiveness of the treatment was assessed using the following criteria: