Clinical bottom line
Optical coherence tomography (OCT) has become an indispensable tool for early detection and monitoring of retinal toxicity induced by systemic medications such as hydroxychloroquine and others. Advances in retinal layer segmentation and angiographic imaging enhance sensitivity to subtle structural and microvascular changes before clinical symptoms arise. These improvements facilitate timely intervention to prevent irreversible vision loss. However, interpretation requires expertise and correlation with clinical context to avoid overdiagnosis. OCT should be integrated into routine screening protocols for at-risk patients on potentially retinotoxic therapies (Ahn et al., 2025; Servushan et al., 2023).
What the evidence shows
OCT enables high-resolution cross-sectional imaging of retinal architecture, allowing quantitative analysis of retinal thickness and layer integrity. Ahn et al. (2025) demonstrated that retinal thickness metrics derived from OCT can detect early retinal alterations in drug toxicity, supporting its diagnostic and monitoring roles.
Hydroxychloroquine toxicity is a well-studied example where OCT reveals parafoveal thinning and disruption of the photoreceptor inner segment/outer segment junction, often preceding visual field defects (Goldman et al., 2018; Handbook of Retinal OCT, 2022). Early identification via OCT permits drug cessation before irreversible damage.
Advancements in OCT angiography (OCTA) provide noninvasive visualization of retinal microvasculature. Sadek et al. (2024) reported that OCTA detects early microvascular changes in systemic hypertension, a model relevant to systemic medication effects on retinal circulation.
Servushan et al. (2023) reviewed recent technological improvements, including enhanced depth imaging and automated segmentation algorithms, which improve reproducibility and detection sensitivity.
Schwartz et al. highlighted the complementary role of angiography alongside OCT in pharmacologic retinal toxicity, aiding comprehensive assessment.
Caveats and uncertainty
OCT findings can be confounded by coexisting retinal diseases, age-related changes, and image acquisition variability.
Thresholds for defining toxicity-related changes lack universal consensus, complicating interpretation.
Limited longitudinal data exist on OCT changes correlating with functional outcomes across diverse medications.
OCTA is a relatively new modality; normative databases and standardized protocols are still evolving.
Clinical correlation remains essential to distinguish true toxicity from benign variations.
How this may change practice
Routine OCT screening should be standard for patients on known retinotoxic systemic agents, with baseline and periodic follow-up imaging.
Incorporation of OCTA may enhance early detection of microvascular involvement, guiding more nuanced risk stratification.
Automated retinal layer analysis tools can support busy clinical workflows and reduce interobserver variability.
Ophthalmologists and prescribing clinicians should collaborate closely to interpret OCT findings in context and adjust therapy accordingly.
Future research will refine imaging biomarkers predictive of toxicity, enabling personalized monitoring strategies.