Early High Postoperative Intraocular Pressure Improved the Predictability of Trabeculectomy in Patients with Primary Open-Angle Glaucoma: A Retrospective Cohort Study.

Introduction: The aim of this study was to investigate the effect of different levels of early intraocular pressure (IOP) on long-term outcomes of patients with primary open-angle glaucoma (POAG) who were treated with primary trabeculectomy.

Methods: This was a retrospective cohort study, with a total of 74 patients (90 eyes) with POAG who were treated with trabeculectomy surgery at a single center from 2021 to 2022. Based on IOP at 1 day after surgery, they were divided into the high IOP group (≥15 mm Hg) and the low IOP group (<15 mm Hg). The Student's t test and a chi-square test were used to compare the differences between the two groups. The generalized estimating equation model compared the included binocular data to adjust for internal correlations between the two eyes of the same subject. The Kaplan-Meier method compared the surgical success rates of the two groups. Besides, to identify the relationship between IOP at different postoperative time points and IOP at 1-year follow-up, the Spearman correlation analysis was established.

Results: A total of 90 eyes (74 patients) with POAG were included in this investigation. After a 1-year follow-up, both the qualified surgical success rates in the high IOP group and the low IOP group were 92.3% and 92.2%, respectively, and there was no statistically significant difference between them (p = 0.890). The rate of bleb massage in the high IOP group was 82.1% (32 eyes) which was significantly higher than in the low IOP group (19.6%, 10 eyes) (p < 0.001). In the Spearman correlation analysis, it was observed that in the high IOP group, the significant correlation with IOP at 1 year emerged at 1 week after surgery (r = 0.496, p = 0.002) and a higher correlation at 1 month after surgery (r = 0.515, p = 0.002). In the low IOP group, the significant correlation with IOP at 1 year emerged at 3 month after surgery (r = 0.314, p = 0.038) and a higher correlation at 6 month after surgery (r = 0.592, p < 0.001).

Conclusion: In the POAG patients with primary trabeculectomy, we demonstrated that compared with the low IOP group, the high IOP group could provide a similar surgical success rate while requiring a higher frequency of bleb massage. In addition, in the high IOP group, IOP at 1 month after surgery predicted long-term IOP control outcomes.