Hydroxychloroquine Retinopathy - Insensitivity of Retinal Nerve Fiber Layer Thickness Measurements as a Screening Test
This 60 year old woman with rheumatoid arthritis had taken 400 mg/d of hydroxychloroquine from 1971 until 2000 when retinopathy was diagnosed and her medication stopped. She weighed 120 pounds and was 66 inches tall. Therefore, she was overdosed at 7.33 mg/kg/d. Her cumulative dose was 4234 grams. When examined in 2012, both eyes showed a bulls-eye maculopathy (left panel, white arrows), yet her retinal nerve fiber layer as measured with the Spectralis spectral domain optical coherence tomography instrument (SD-OCT ) was of normal thickness in all sectors bilaterally. The globally averaged nerve fiber layer thickness was 95 microns on the right and 88 microns on the left (right panel). Her 10-2 visual fields, macular SD-OCT line scans, fundus autofluorescence images, and multifocal electroretinograms were abnormal and typical for hydroxychloroquine retinopathy bilaterally (not shown).