SMR analysis confirmed these relationships using eQTLGen data, showing significant associations between Cathepsin H variants and DR risk (OR = 1.0715, 95% CI: 1.0220–1.1235, P = 4.2 × 10− 3, P_HEIDI = 0.8443), PDR (OR = 1.0809, 95% CI: 1.0295–1.1349, P = 1.8 × 10− 3, P_HEIDI = 0.8063), and diabetic maculopathy (OR = 1.0996, 95% CI: 1.0168–1.1893, P = 0.0175, P_HEIDI = 0.5574). Here, CTSH is linked to diabetic maculopathy.