Hydroxychloroquine Retinopathy in Systemic Lupus Erythematosus: Risk Factors, Screening, and Emerging Biomarkers

Hydroxychloroquine (HCQ) is a cornerstone therapy for systemic lupus erythematosus (SLE) because of its immunomodulatory and anti-inflammatory benefits. However, long-term exposure can cause HCQ-induced retinopathy, a potentially irreversible adverse effect in which early detection is critical. This review summarizes the literature on the reported prevalence of HCQ-related retinal toxicity in SLE, highlights consistently supported risk modifiers (including higher daily dose relative to real body weight, longer duration/cumulative exposure, and renal impairment), and synthesizes current screening strategies centered on multimodal structural and functional testing. Spectral-domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF), standard automated perimetry, and multifocal electroretinography (mfERG) are frequently emphasized as complementary tools for earlier detection, while emerging approaches such as OCT angiography-derived metrics and pharmacokinetic measures remain exploratory. Real-world screening adherence is often suboptimal, underscoring the need for implementation strategies that align dosing, risk stratification, and ophthalmic monitoring. Future work should standardize diagnostic definitions, clarify optimal screening intervals across risk strata, and prospectively validate promising biomarkers and automated screening workflows.