Many retinal diseases begin long before patients experience noticeable vision loss.Clinicians frequently manage patients with early age-related macular degeneration, diabetes or glaucoma who maintain normal visual function despite underlying disease processes.This clinical reality raises an important question: Are we detecting retinal disease at the point at which we have the greatest opportunity to preserve vision?Emerging evidence suggests that structural retinal damage often represents a relatively late stage of disease progression. Functional abnormalities and metabolic stress regularly