Introduction: To measure the prevalence of hydroxychloroquine retinopathy in patients attending a hydroxychloroquine monitoring service using 2018 Royal College of Ophthalmologists diagnostic criteria.
Methods: A service evaluation audit of a hydroxychloroquine retinopathy monitoring service was undertaken. Results of Humphrey 10-2 field tests, spectral-domain optical coherence tomography and fundus autofluorescence were collected with data on dose, weight, duration of treatment, estimated glomerular filtration rate, and concurrent tamoxifen therapy. Visual field tests were assessed as reliable or unreliable, and classified as normal, hydroxychloroquine-like, poor test or related to other pathology. Cases of definite and possible retinopathy were identified using the 2018 RCOphth criteria.
Results: There were 1976 attendances over two years of 1597 patients. Seven hundred and twenty-eight patients had taken hydroxychloroquine for less than 5 years and 869 had taken hydroxychloroquine for 5 years or more. Fourteen patients were identified with definite hydroxychloroquine retinopathy (1.6%), and 41 patients with possible retinopathy (4.7%). Sixty-seven per cent of 861 visual fields were performed reliably, with 66.9% classified as normal, 24.9% as poor test, 5.2% hydroxychloroquine-like and 3.0% abnormal due to other pathology.
Conclusions: The 1.6% prevalence of hydroxychloroquine retinopathy is lower than the previously reported prevalence of 7.5% as reported by Melles and Marmor JAMA Ophthalmol 132: 1453-60 (2014). This is because of a difference in the diagnostic criteria. Both definite and possible retinopathy would meet the diagnostic criteria of the Melles and Marmor study; 6.3% in our data, compared with 7.5%, a much smaller difference and likely to be explained by differences in the risk characteristics of the two groups.