Known frequent ocular toxicities include lacrimal drainage obstruction caused by S-1, corneal disorders caused by cytarabine and S-1, and retinal detachment caused by mitogen-activated protein kinase (MEK)-inhibitors, and other ocular toxicities caused by ICIs, fibroblast growth factor receptor (FGFR) inhibitors, anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibodies, and some ADCs [1, 2]. The gene discussed is ERBB2; the disease is retinal detachment.