Association of biometric factors with anterior chamber angle widening and intraocular pressure reduction after uneventful phacoemulsification for cataract

Purpose: To evaluate anterior chamber biometric factors associated with the degree of angle widening and intraocular pressure (IOP) reduction after phacoemulsification.

Setting: University of California, San Francisco, California, USA.

Design: Case series.

Methods: Anterior chamber parameters obtained by anterior segment coherence tomography were compared preoperatively and 3 months postoperatively. Measurements included the angle opening distance 500 μm anterior to the scleral spur (AOD500), trabecular-iris space area 500 μm from the scleral spur (TISA500), iris curvature (I-Curv), anterior chamber angle (ACA), trabecular-iris space area, anterior chamber volume, anterior chamber width, and lens vault (LV).

Results: The study enrolled 73 eyes. The mean patient age was 77.45 years ± 7.84 (SD); 65.75% of patients were women. From preoperatively to 3 months postoperatively, the mean AOD500 increased significantly (0.254 ± 0.105 to 0.433 ± 0.108 mm) and the mean IOP decreased significantly (14.97 ± 3.35 to 12.62 ± 3.37 mm Hg) (P<.001). The reduction in IOP was correlated with the increase in AOD500 (r = 0.240, P=.041) and preoperative LV (r = 0.235, P=.045). After adjusting for related factors, AOD500 widening was positively correlated with LV (β = 0.458, P=.044) and I-Curv (β = 0.235, P=.043) and negatively correlated with preoperative TISA500 (β = -0.269, P=.025) and ACA (β = -0.919, P=.027).

Conclusions: Surgically induced AOD widening was significantly correlated with anterior chamber biometric factors. Preoperative LV appears to be a significant factor in angle widening and IOP reduction after phacoemulsification.