Consistent with previous studies, our results indicated not only that GPX4 and SLC7A11 protein expression was remarkably decreased, but also that ACSL4, FTH1, and NCOA4 protein levels were dramatically increased in HG-induced 661W cells and in mouse photoreceptor cells, suggesting that photoreceptor ferroptosis began as early as 1 month after diabetes induction. The gene discussed is NCOA4; the disease is diabetes mellitus.