Severe retinopathy induced by low-dose tamoxifen: a 10-month follow-up analysis based on multimodal imaging

Abstract Background: Tamoxifen retinopathy (TAM-R) typically occurs with prolonged and high-dose administration. This study presents an uncommon instance of severe TAM-R following 3.75 years of low-dose tamoxifen (10mg/day) treatment, totaling 450mg cumulatively. Case Report: A 35-year-old female with obesity (BMI 47.86 kg/m²) presented with bilateral vision loss. Multimodal imaging (OCT/OCTA/FFA/FAF) revealed retinal crystal deposition, macular pseudocyst, IS/OS rupture, and deep capillary plexus loss. Despite discontinuation of medication, visual acuity remained poor (BCVA .15 right eye, .03 left eye). At the 10-month follow-up, there was partial structural improvement, yet IS/OS impairment persisted. Conclusion: This case challenges traditional TAM-R dosage thresholds, suggesting obesity may exacerbate toxicity. Baseline OCTA vascular markers correlate with irreversible visual impairment, offering novel insights for prognostic evaluation.