To analyze the occurrence of early hypotony after the intravitreal injection of anti-vascular endothelial growth factor (VEGF) and its risk factors.

A case-control study was performed.One hundred and twenty-seven eyes of 127 patients with fundus vascular disease who received intravitreal injections of anti-VEGF drugs were enrolled in Henan Provincial People's Hospital from January 2020 to January 2022.Of the 127 patients, there were 71 males and 56 females, with an average age of (61.85±11.53) years and a mean intraocular pressure of (15.28±3.71)mmHg (1 mmHg=0.133 kPa). All subjects were intravitreally injected with 0.05 ml of anti-VEGF drugs, including 56 cases receiving ranibizumab, 38 cases receiving conbercept and 33 cases receiving aflibercept.The intraocular pressure was measured with a non-contact tonometer at 30 minutes, 1 hour and 2 hours after the injection.The cases were grouped as hypotony group or non-hypotony group according to the intraocular pressure of subjects was less than 10 mmHg or not.The differences in sex, age, distribution of left eye and right eye, disease type, intraocular pressure before injection, injection frequency, lens status, drug type, injection timing, injection site, with or without high myopia, with or without a history of glaucoma or ocular hypertension, and with or without a history of vitreoretinal surgery were analyzed to investigate the factors with a P-value <0.05, which were used as the independent variable and the occurrence of hypotony as the dependent variable in logistic regression analysis to explore the risk factors for hypotony.This study adhered to the Declaration of Helsinki.The study protocol was approved by the Ethics Committee of Henan Eye Hospital (No.HNEEC-2022-42).

Hopotony occurred in 8 eyes within 2 hours after the injection.There were significant differences in intraocular pressure at different time points before and after injection between the hypotony and non-hypotony groups (F_group=62.177, P<0.001; F_time=25.128, P<0.001). The intraocular pressure of the hypotony group at 30 minutes, 1 hour and 2 hours after injection were lower than before injection, and the intraocular pressure of the non-hypotony group was higher at 30 minutes after injection than before injection (all at P<0.05). The average reduction of intraocular pressure of the hypotony group was 7.88, 7.63 and 7.23 mmHg at 30 minutes, 1 hour and 2 hours after the injection, and the intraocular pressure returned to baseline level at 1 day after injection.There was no significant difference in sex, distribution of left and right eyes, disease type, pre-injection intraocular pressure, injection frequency, lens status, drug type, injection timing, injection site, with or without a history of high myopia and with or without a history of glaucoma or ocular hypertension between the two groups.There were significant differences in age and with or without a history of vitreoretinal surgery between the two groups (t=8.265, P<0.001; χ²=6.907, P=0.035). Multivariate logistic regression analysis showed younger patients and having a history of vitreoretinal surgery were the risk factors for early hypotony after anti-VEGF intravitreal injection (odds ratio=88.563, P<0.001; odds ratio=20.991, P=0.009).

Patients with younger age and having a history of vitreoretinal surgery are susceptible to early hypotony after anti-VEGF intravitreal injection.

Angiogenesis inhibitors; Vascular endothelial growth factors; Intravitreal injections; Hypotony; Risk factors