Screening for hydroxychloroquine retinopathy

Editor—The editorial on screening for hydroxychloroquine retinopathy covered none of the recent publications on the subject and failed to distinguish those cases in which screening is necessary.¹

Levy et al’s review of 1505 patients found no cases of proved retinopathy in patients taking <6.5 mg/kg/day of hydroxychloroquine but one case in a patient taking a higher dose.² Silman and Shipley point out that “bull’s eye retinopathy” can occur in patients not taking hydroxychloroquine.³ Indeed, Scherbel et al reported that the incidence of maculopathy in patients with rheumatoid arthritis was greater in untreated patients than in those receiving hydroxychloroquine or chloroquine.⁴ Mavrikakis and colleagues’ study of 360 patients identified two cases of retinopathy with daily doses <6.5 mg/kg.⁵ In both of these cases the cumulative dose exceeded 700 g.

Research confirms that hydroxychloroquine is safer than chloroquine and that at a daily dose of hydroxychloroquine <6.5mg/kg the risk of retinopathy is negligible if patients are younger than 60 years with normal renal and liver function.² In these circumstances regular screening is unnecessary, although we suggest recording visual acuity before starting treatment.

We recommend ophthalmic screening in the following patients, for whom evidence suggests an increased risk of hydroxychloroquine retinopathy: patients with known retinal disease or visual impairment; with renal or liver impairment; over 60 years old; receiving a daily dose greater than 6.5mg/kg; or who have received an accumulated dose above 500 g.

Screening should take the form of an initial ophthalmic assessment and annual ophthalmic review for the duration of treatment. The best form of ophthalmic assessment is unclear and currently depends on the preferences of the screening ophthalmologist. We recommend visual acuity, automated perimetry, and funduscopy, ideally with initial fundal photographs. Fluorescein angiography should be used in elderly people to differentiate between age related macula degeneration and hydroxychloroquine toxicity when continuing treatment with hydroxychloroquine is deemed essential.

The decision to stop treatment will depend on the opinion of both the ophthalmologist and the treating physician, taking into account the likelihood that retinal and visual changes are due to hydroxychloroquine, the extent of retinal damage, and the risk of increased disease activity after stopping treatment. It should be noted that effects of stopping treatment are uncertain as both progression and reversibility have been reported.