The present invention relates generally to the field of treatment and prophylaxis of retinal degenerative diseases. More particularly, the present invention contemplates a method for preventing, reducing the risk of development of, or otherwise treating or ameliorating the symptoms of, age-related macular degeneration (AMD) or related retinal conditions in mammals and in particular humans. The present invention further provides therapeutic compositions enabling dose-dependent or dose-specific administration of agents useful in the treatment and prophylaxis of age-related macular degeneration or related retinal degenerative conditions.