Forward-direction GSMR analysis showed that Cathepsin H was positively associated with DR (OR = 1.0494, 95% CI = 1.0151–1.0849, P = 4.5 × 10− 3), proliferative DR subtype PDR (OR = 1.0581, 95% CI = 1.0225–1.0950, P = 1.2 × 10− 3), and diabetic maculopathy (OR = 1.0751, 95% CI = 1.0174–1.1360, P = 0.0101). Here, CTSH is linked to diabetic maculopathy.