Hydroxychloroquine, dosage parameters and retinopathy.

In a study designed to determine the presence of retinopathy in patients taking hydroxychloroquine we compared 82 patients attending a rheumatology clinic who had taken hydroxychloroquine for over 1 year with controls. Outcome measurements included fundoscopy, fundus photography and automated computerized visual fields of the macular area. No patient was found to have retinopathy. No correlation could be found between indices of visual field function and total drug usage, average daily dose, dosage in mg/kg body weight or duration of treatment. Retinopathy is unlikely to occur at dosages of hydroxychloroquine of less than 6.5 mg/kg body weight with under 10 years of treatment. Present guidelines for ophthalmic screening of patients on antimalarial therapy are too rigorous and visual field testing if not of benefit. Further recommendations are made for ophthalmic supervision.