Hydroxychloroquine (Ophthalmic Toxicity Monitoring)

How it works

Hydroxychloroquine accumulates in the retinal pigment epithelium and can, with prolonged cumulative exposure, cause a characteristic bull's-eye maculopathy through disruption of retinal cell metabolism and lysosomal function, leading to irreversible photoreceptor damage.

Prescribing in practice

• Because established hydroxychloroquine retinopathy is irreversible and can progress even after stopping, baseline and regular ongoing retinal screening is essential to detect pre-symptomatic change.
• Risk rises with duration of therapy, higher weight-adjusted daily dose, concurrent tamoxifen use and significant renal impairment.
• Screening combines spectral-domain optical coherence tomography with automated visual field testing, supplemented by other modalities where available.

Monitoring

A baseline ophthalmic assessment is recommended near the start of long-term treatment, with formal annual retinopathy screening commencing after several years of therapy or earlier in higher-risk patients.

Counselling the patient

• Attend your scheduled eye-screening appointments, as early damage causes no symptoms.
• Report any new problems with central or colour vision, or difficulty reading, between visits.
• Do not exceed the prescribed dose, since the risk to the retina relates to long-term cumulative exposure.

Evidence & guidelines

Royal College of Ophthalmologists guidance sets out structured hydroxychloroquine retinopathy screening using optical coherence tomography and visual fields to detect toxicity before vision is lost.