Factors affecting refractive outcome after cataract surgery in primary angle-closure glaucoma.

Background: To evaluate the biometric factors associated with the accuracy of intraocular lens power predictions for cataract surgery in primary angle-closure (PAC) or primary angle-closure glaucoma (PACG) eyes.

Design: Cross-sectional study PARTICIPANTS: This study included 103 PAC or PACG patients who had undergone cataract surgery.

Methods: All participants underwent anterior-segment optical coherence tomography preoperatively. Two novel biometric factors - the relative lens vault (the ratio of lens vault to anterior vault) and the anterior vault (the sum of lens vault and anterior chamber depth) - were measured using customized software. The powers of the implanted intraocular lens and the actual postoperative refractive errors were compared. The mean refractive error and the median absolute error were calculated and compared using repeated measures ANOVA and Wilcoxon matched-pairs signed-rank test. The biometric factors associated with the postoperative refractive error were investigated by multivariate regression analysis.

Main Outcome Measures: Preoperative anterior-segment biometric factors, difference between predicted and actual postoperative refraction.

Results: The Haigis, Hoffer Q and SRK/T formulas all showed a slight tendency toward resultant hyperopia, respectively (P < 0.001, P = 0.05, P = 0.003). The Hoffer Q formula had the least prediction error (P < 0.001). In the multivariate regression analysis, the relative lens vault was the only independent factor predicting postoperative refractive error (β = 0.392, P = 0.011).

Conclusion: Intraocular lens power predictions for cataract surgery in PAC or PACG patients can be inaccurate. Such results might be associated with anterior-segment biometric factors. Preoperative relative lens vault appears to be a significant factor predicting refractive outcome after cataract surgery in patients with PAC or PACG.