Changes in intraocular pressure following intravitreal dexamethasone implant in patients with history of glaucoma filtration surgery

Purpose This study aimed to evaluate changes in intraocular pressure following intravitreal dexamethasone implant injection, specifically in patients undergoing glaucoma filtration surgery. Methods The degree of increase in intraocular pressure was compared retrospectively among three groups. Group 1 comprised patients who underwent prior glaucoma filtration surgery (54 eyes). Group 2 included patients with or suspected glaucoma without such surgical history (20 eyes). Group 3 included patients without glaucoma (33 eyes). Pressure measurements were taken before the injection and at 1, 2, 3, and 6 months post-injection. A subgroup analysis was performed for pressure > 35 mmHg, > 30 mmHg, > 25 mmHg, and a difference > 10 mmHg between the peak and baseline pressure. Results Group 1 consistently displayed lower pressures compared with Group 2, with significant difference at both 1- and 6-month post-injections (15.09 mmHg vs. 18.10 mmHg, P = 0.042 and 13.91 mg vs. 17.25 mmHg, P = 0.040). The proportion of patients in Group 1 and Group 3 with pressures > 25 mmHg, > 30 mmHg, and a difference > 10 mmHg did not significantly differ (15.6% vs. 9.5%, P = 0.231; 3.1% vs. 2.3%, P = 0.867; and 17.1% vs. 7.1%, P = 0.231). Notably, Group 2 exhibited a significantly higher proportion within each category (> 25 mmHg, 24.0%; > 30 mmHg, 20.0%; > 10 mmHg difference, 28.0%). Conclusion Intravitreal dexamethasone implant did not increase the risk of elevated intraocular pressure in patients with a history of glaucoma filtration surgery compared with patients with suspected glaucoma; the risk was similar to those without glaucoma.