The clinical experiences with 1,500 patients receiving chloroquine or hydroxychloroquine over a 15-year period are reviewed. Forty-six patients with confirmed irreversible, bilateral, early chloroquine retinopathy have been followed prospectively since 1980. Patients presenting with normal color vision and relative paracentral scotomas appear not to progress over short-term follow-up of five years. Retinopathy in patients presenting with less than 20/20 vision, abnormal color vision, and positive fluorescein angiography may progress even if treatment with the medication is discontinued. The Amsler grid is an effective method of screening patients taking antimalarial agents for early relative paracentral scotomas. Color vision testing and fluorescein angiography are useful in elderly patients with age-related macular disease when visual field testing is unreliable.