Chloroquine retinopathy is an iatrogenic disease caused by chloroquine, a drug formerly used commonly in the treatment of rheumatologic diseases such as rheumatoid arthritis and systemic lupus erythematosus. In the United States and Canada, chloroquine usage has nearly vanished, but in Europe the drug continues to be used. Adjusted daily dosage based on the smaller of actual and ideal body weight and cumulative dosage of drug are the two most important factors associated with retinopathy. The characteristics of chloroquine retinopathy are similar to those of hydroxychloroquine retinopathy. Please see documents under that heading for more insight into this topic.