Ophthalmologic considerations and testing in patients receiving long-term antimalarial therapy.

We do not as yet understand all the mechanisms involved in retinal toxicity. Such risk is lower with hydroxychloroquine than with chloroquine. The risk of true retinopathy rises with duration of therapy. The benefit/risk ratio for hydroxychloroquine is at least equal to or better than that of chloroquine, and when the currently recommended dosages of 400 mg per day of hydroxychloroquine and 250 mg per day of chloroquine are not exceeded, this ratio is medically and ophthalmologically acceptable. The most useful tests to detect retinopathy are ophthalmoscopic and/or photographic observation of the macular area for changes in pigmentation, sensitive central visual field testing, and automated computerized perimeter. These tests can be conducted by the attending physician provided that (1) baseline ophthalmologic studies are done (to exclude pre-existing ocular abnormalities); (2) such studies are conducted every six months thereafter; and (3) the patient with ocular abnormalities is immediately referred to an ophthalmologist for further evaluation, even in the absence of symptoms.