Effect of Shallow Anterior Chamber on Postoperative Refractive Status in Patients of Age-Related Cataract

To assess how shallow anterior chamber depth (ACD) affects refractive error (RE) after cataract surgery and compare modern intraocular lens (IOL) formulas in patients with normal axial length.

This prospective study enrolled patients undergoing phacoemulsification with IOL implantation at Jinan No. 2 People's Hospital (June 2023-December 2024). Patients were divided based on ACD into two groups. Biometrics were measured using IOLMaster 700, and IOL power was calculated with the Barrett Universal II (BUII) formula. Patients were reassessed at 1 and 3 months postoperatively. We analyzed correlations between RE and biometrics and compared BUII, Kane, EVO 2.0, and Hill-RBF 3.0 formulas.

A total of 103 patients were divided into two groups: shallow (ACD < 2.5 mm, n = 57) and normal (ACD 2.5-3.5 mm, n = 46). Group Shallow had significantly greater RE (+0.451 ± 0.328 vs. -0.002 ± 0.277 D; p < 0.001) and greater postoperative ACD deepening (2.19 ± 0.26 mm vs. 1.43 ± 0.25 mm; p < 0.001) than group normal. Hyperopic shift correlated negatively with preoperative ACD and positively with ACD change (both p < 0.001). In shallow eyes, all formulas showed a hyperopic tendency, but BUII had the lowest mean absolute error (0.470 D, p < 0.001) and highest proportion of eyes within ±0.50 D (54.39%). In normal eyes, all formulas performed comparably well.

Shallow ACD independently increases hyperopic shift risk. While all formulas are effective in normal eyes, BUII is superior in shallow chambers. Preoperative ACD and lens thickness assessment is crucial, and slight IOL power adjustment may optimize outcomes in shallow ACD cases.