To the Editor.
—The article by Tobin et al published in the January Archives (1982;100:81-83) on the safety of hydroxychloroquine sulfate recalls my experience with this drug in rheumatic diseases. During the past 15 years, I have followed up approximately 100 patients with rheumatoid arthritis and lupus erythematosus who were given hydroxychloroquine sulfate in doses of 200 to 400 mg/day. The average length of drug use was 36 months, with 12 patients using the drug up to eight years. In this whole group, no functional visual or anatomic ocular defects were noted on ocular examination.Since central vision tends to be most affected by this drug, it is my recommendation to use Amsler's charts, principally the red chart, to pick up the smallest and earliest central or paracentral defects.