Structural and microvascular retinal changes in tamoxifen users assessed by optical coherence tomography and OCT...

To investigate subclinical retinal structural, microvascular, and outer retinal reflectivity changes in women receiving tamoxifen therapy for at least 12 months without clinically apparent retinopathy.

A total of 48 eyes from 48 women who had been receiving tamoxifen therapy for at least 12 months and 52 eyes from 52 age-matched healthy female controls were included in the study. Only the right eye of each participant was analyzed to avoid inter-eye correlation. All participants underwent comprehensive ophthalmic examination, swept-source optical coherence tomography (OCT), OCT angiography (OCTA), and quantitative outer retinal reflectivity analysis using ImageJ. Retinal thickness, choroidal thickness, and OCTA-derived vessel density parameters were compared between groups. Absolute and RPE-normalized reflectivity values of the retinal pigment epithelium (RPE), ellipsoid zone (EZ), and external limiting membrane (ELM) were quantified using standardized vertical line-profile analysis.

The mean age was 45.9 ± 5.4 years in the tamoxifen group and 46.6 ± 4.7 years in the control group. Retinal thickness parameters, choroidal thickness, and OCTA-derived vessel density metrics of the superficial and deep capillary plexuses and choriocapillaris were comparable between tamoxifen users and controls (all p > 0.05). Mean and central RPE reflectivity were significantly higher in the tamoxifen group than in controls (RPEav, p = 0.037; RPEc, p = 0.003), whereas EZ and ELM reflectivity values and all RPE-normalized relative reflectivity indices did not differ significantly between groups. A localized increase in outer retinal vessel density was observed in the superior sector in tamoxifen users, without corresponding widespread microvascular alterations. No significant correlations were found between duration of tamoxifen exposure and OCT, OCTA, or reflectivity parameters.

Tamoxifen therapy for at least 12 months is associated with selective increases in RPE reflectivity despite preserved retinal structure and microvasculature. Quantitative reflectivity analysis may serve as a sensitive, noninvasive marker for early, subclinical retinal stress preceding clinically apparent tamoxifen retinopathy.