Role of microperimetry to detect early visual function deficits in patients with hydroxychloroquine retinal...

Chloroquine and its analogue hydroxychloroquine (HCQ) are antimalarial drugs used in various rheumatological and dermatological diseases. HCQ retinal toxicity (HCQ-RT) is uncommon but early detection of retinal toxicity and prompt cessation of the medication can usually prevent significant visual function (VF) losses. The risk of retinopathy from HCQ depends on the duration of drug use, cumulative exposure to the drug, age, presence of liver or renal disease and underlying retinal disease. The screening of all patients on HCQ for early detection of retinal toxicity is recommended. Routine screening tests include structural imaging with spectral domain optical coherence tomography and fundus autofluorescence and functional testing with visual fields and electrophysiology. Functional testing is challenging as it requires patient co-operation. No single test has shown high sensitivity or specificity. Microperimetry (MP) is an emerging VF measure that allows the evaluation of mesopic and scotopic macular sensitivity by the detection of early scotomas and a change in normal fixation. It employs computerized threshold perimetry with real-time fundus imaging. This is a scoping review of the literature to provide updates on recent studies that have used MP as an ancillary diagnostic test for detecting HCQ toxicity in the retina.