The Effect of Phacoemulsification on the Intraocular Pressure of Patients with Open-angle Glaucoma: A Systematic Review and Meta-Analysis

Precis: There is evidence that cataract surgery can reduce intraocular pressure in patients with primary open angle-, normal tension-, or exfoliative glaucoma. The complete effect of phacoemulsification is masked by topical intraocular pressure-lowering medications. Purpose: To assess the impact of phacoemulsification and intraocular lens implantation on intraocular pressure (IOP) level in individuals with primary open-angle glaucoma (POAG), exfoliative glaucoma (XFG), exfoliation syndrome (XFS), normal tension glaucoma (NTG), ocular hypertension (OH) or healthy controls 12 months after the surgery. Methods: In July 2023, a comprehensive literature review was conducted across six databases. The analysis focused on the phacoemulsification arms of randomized controlled trials (RCTs). The primary outcome of interest was the mean IOP change observed 12 months after phacoemulsification. Results: This meta-analysis included nine arms from nine RCTs, comprising a total of 502 participants. Overall, the average IOP was reduced by 3.77 mmHg (95%CI: −5.55 to −1.99, I 2 =67.9%) 12 months after surgery. The subgroup analysis, focused on whether a washout period was employed before measuring IOP, revealed that studies with a washout period exhibited a more pronounced IOP reduction of 5.25 mmHg (95%CI: −7.35 to −3.15, I 2 =0%), while studies without a washout period exhibited a reduction of 3.13 mmHg (95%CI: −5.46 to −0.81, I 2 =75.8%). The sensitivity analysis for the latter group, excluding an outlier study, showed a reduction of 1.81 mmHg (95%CI: −2.95 to −0.67, I 2 =0%). Conclusions: The findings of this systematic review and meta-analysis indicate that cataract surgery meaningfully lowers IOP in POAG, XFG/XFS, or OH 12 months after surgery. However, the use of topical medications masks the precise impact of phacoemulsification upon postoperative IOP. Further research using appropriate washout periods is warranted.