Objective To observe and analyze the risk factors of secondary intraocular hypertension in diabetic macular edema (DME) patients after treatment with dexamethasone vitreous cavity implant (DEX). MethodsA retrospective observational study. A total of 352 patients with type 2 diabetes mellitus (T2DM) secondary macular edema diagnosed by ophthalmic examination and treated with DEX in Department of Ophthalmology of Harbin 242 Hospital from January 2016 to March 2022 were included in the study. Among them, 221 were males and 131 were females, with the mean age of (55.56±8.09) years. There were 194 patients with disseminated macular edema, 158 patients with cystoid macular edema. All patients underwent vitreous cavity implantation of DEX. Intraocular pressure (IOP) was measured once a month for 3 months after treatment, with IOP over than 25 mm Hg (1 mm Hg=0.133 kPa) or higher than 10 mm Hg from baseline as secondary intraocular hypertension. The relevant clinical data were collected, and the risk factors of secondary intraocular hypertension in DME patients after DEX treatment were analyzed by binary logistic regression. ResultsAmong 352 patients, 116 patients (32.95%, 116/352) were in the intraocular hypertension. Among them, 29 patients (25.00%, 29/116), 69 patients (59.48%, 69/116) and 18 patients (15.52%, 18/116) occurred intraocular hypertension at 1, 2 and 3 months after treatment, respectively. Compared with the normal IOP group, the IOP in the intraocular hypertension group increased significantly at 1, 2 and 3 months after treatment, with statistical significance (t=10.771, 21.116, 13.761; P＜0.001). Compared with normal IOP group, the patients in the intraocular hypertension group had younger age (t=6.967), longer duration of diabetes (t=5.950), longer axial length (AL) (t=14.989), higher proportion of DME grade 3 (Z=6.284), higher proportion of DEX implantation in pars plana (χ2=23.275), and higher HbA1c level (t=10.764), the differences were statistically significant (P＜0.05). Logistic regression analysis showed that longer AL [odds ratio (OR)=1.428, 95% confidence interval (CI) 1.054-1.934], DEX implantation in pars plana (OR=1.358, 95%CI 1.063-1.735), and higher HbA1c (OR=1.702, 95%CI 1.225-2.366) were the risk factors for secondary intraocular hypertension in DME patients after DEX treatment (P＜0.05), older age was a protective factor (OR=0.548, 95%CI 0.380-0.789, P＜0.05). ConclusionsLong AL, DEX implantation in pars plana and high HbA1c are the risk factors for secondary intraocular hypertension after DEX treatment in DME patients, older age is a protective factor.