Hydroxychloroquine and visual screening in a rheumatology outpatient clinic

Objective - To review 10 years' data relating to visual screening of patients taking hydroxychloroquine. Methods - Following baseline visual assessment, ophthalmic monitoring was carried out at six monthly intervals on 758 patients while on hydroxychloroquine. This consisted of corrected visual acuity, central field screening with a red Amsler grid, slit lamp examination, and retinoscopy. Results - None of the patients suffered visual impairment from retinal toxicity, though 12 reported visual disturbance. This was related to ocular muscle imbalance in four. In the remainder, none of the ocular findings was directly attributable to hydroxychloroquine. Ten patients reported defects when tested with a red Amsler grid. None was related to retinal toxicity. Seven patients developed corneal drug deposits which cleared on stopping or reducing the dose of hydroxychloroquine. Conclusions - The findings support the view that following baseline ophthalmic examination for patients receiving hydroxychloroquine, regular ophthalmic screening is not required if the daily dose is less than 6.5 mg kg(-1) and the cumulative dose is less than 200 g.