Advances in Research on Ocular Adverse Effects and Mechanisms of Aromatase Inhibitors and Selective Estrogen Receptor Modulators

Aromatase inhibitors (AIs) and selective estrogen receptor modulators (SERMs) are key medications for treating estrogen receptor (ER)-positive breast cancer. AIs suppress estrogen production, while SERMs antagonize estrogen receptors, thereby downregulating the expression of proto-oncogenes such as Cyclin D1 and Cyclin-dependent kinase 4/6 (CDK4/6), ultimately inhibiting the proliferation of breast cancer cells. ERs are primarily distributed in tissues including the breast, uterus, bones, and eyes. In the eyes, ERs are present in ocular tissues such as the lacrimal glands, lens, and retina. Estrogen plays crucial roles in maintaining tear secretion, preserving lens transparency, and stabilizing the retina. Consequently, AIs and SERMs can cause ocular adverse effects, including dry eye syndrome, cataracts, and retinopathy. This review summarizes the ocular adverse effects induced by AIs and SERMs and explores their underlying mechanisms, aiming to provide references for optimizing therapeutic regimens of these drugs and developing novel anti-breast cancer drugs.