Hydroxychloroquine Toxicity - Symmetry of Changes

Series of static macular perimetry tests of the both eyes of a 78 year old woman with rheumatoid arthritis taking 400 mg/d of hydroxychloroquine for 15 years. She was 5 feet tall and weighed 100 pounds. Her daily dose was 8.8 mg/kg/d. No visual fields were available before 2008, when she already showed signs of a paracentral scotoma. These fields were interpreted as normal by her ophthalmologist each year. In rough terms, the development of toxicity is symmetric, although the left eye seems accelerated relative to the right eye over the 4 year period of follow-up. Great asymmetry is a characteristic that would tend to make a clinician question the diagnosis of hydroxychloroquine retinopathy.