Two years' experience of screening for hydroxychloroquine retinopathy

The Royal College of Ophthalmologists (RCOphth) recently produced new guidelines for the screening of hydroxychloroquine (HCQ) retinopathy. New imaging techniques have suggested an increased prevalence of retinopathy (7.5%) compared with previous studies (0.5%).

We collected prospective data from all patients referred to Sunderland Eye Infirmary, Sunderland for HCQ screening. Patients were screened according to RCOphth guidelines. In addition to retinal images, the data recorded included visual acuity, visual fields and multifocal electroretinography as appropriate, the patient's age, diagnosis, weight, renal function and use of tamoxifen.

Of the 678 patients screened, 333 were categorised to be at risk (251 patients had been on HCQ >5 years, 117 had an estimated glomerular function rate <60 ml/min/1.73 m², and 46 were on a dose >5 mg/kg/day). Eighty patients had multiple risk factors, 31 had been on doses of >5 mg/kg/day for >5 years. One hundred and sixty-eight of these patients have now been screened twice. The prevalence of HCQ retinopathy was 2/678 (0.3%) of all screened, 2/333 (0.6%) of patients at risk.

Our results show a far lower rate of retinopathy compared to the widely reported figure taken as standard by the RCOphth. This may be multifactorial: this prospective analysis has fewer patients taking higher doses of HCQ and shorter follow up, the comparison of serial images may highlight more cases and in addition, there are significant numbers of patients yet to be referred. Finally, the RCOphth's diagnostic criteria is more exacting than that of the recent literature.