Objective: To define the true risk of hydroxychloroquine (HCQ) retinal toxicity by studying the largest single group yet evaluated.
Methods: Retrospective chart review of all patients in the Kaiser Permanente Medical Care Program, Southern California Region, who had HCQ prescriptions filled from 1991 through 1993 (1,556 patients in 11 medical centers). Of 1,207 charts of patients who took HCQ and had documented ophthalmologic examinations, initial screening identified 21 charts (1.7%) that indicated possible HCQ toxicity.
Results: We identified 1 patient with definite toxicity (1 of 1,207; 0.08%) and 5 other patients with indeterminate but probable toxicity (5 of 1,207; 0.4%). The incidence of definite HCQ retinal toxicity in patients treated with HCQ at <6.5 mg/kg/day was 0.
Conclusion: In HCQ-treated patients whose renal function is normal, routine ophthalmic screening is not indicated if the daily dosage is <6.5 mg/kg. In patients whose daily dosage is >6.5 mg/kg or who have taken HCQ continuously for > 10 years, annual screening may be appropriate.