Changes in anterior chamber biometry and intraocular pressure after uneventful phacoemulsification in non-glaucomatous eyes

Abstract Background: In non-glaucomatous eyes, many factors impact intraocular pressure (IOP) reduction following phacoemulsification. This study aimed to determine the relationship between changes in IOP and alterations in anterior chamber biometric measurements using the Pentacam Scheimpflug anterior segment imaging system before and after uneventful phacoemulsification in non-glaucomatous eyes. Methods: This prospective interventional study included patients with ages of ۲۰ – ۸۰ years, no known systemic diseases, and visually significant cataracts necessitating phacoemulsification with posterior chamber intraocular lens implantation. The preoperative and two-month postoperative IOPs were measured using a Goldmann applanation tonometer, and the iridocorneal angle (ICA) in four quadrants (superior, inferior, nasal, and temporal), anterior chamber depth (ACD), and anterior chamber volume (ACV) were measured using the Pentacam. Results: Forty-two eyes of ۴۲ patients with a mean (standard deviation [SD]) age of ۵۶.۸ (۱۰.۷) years were included; ۲۲ (۵۲%) were men and ۲۰ (۴۸%) were women. The eyes demonstrated statistically significant changes in postoperative IOP, ACD, ACV, and in widening of the ICA (all P < ۰.۰۵), with a mean (SD) IOP reduction of ۴.۵ (۲.۷) mmHg, ACD deepening of ۰.۷ (۰.۶) mm, ACV increase of ۳۳.۲ (۲۱.۱) mm۳, and ICA widening of ۷.۵o (۶.۴o), ۱۲.۴o (۷.۷o), ۹.۱o (۷.۱o), and ۱۱.۵o (۶.۱o) in the superior, inferior, temporal, and nasal quadrants, respectively. A significant positive correlation was detected between pre- and postoperative IOP (r = + ۰.۵۸; P < ۰.۰۰۱) and between pre- and postoperative ACD (r = + ۰.۵۰; P < ۰.۰۰۱). Significant negative correlations were detected between preoperative ACV and changes in ACV (r = - ۰.۴۲; P < ۰.۰۰۱) and between preoperative ICA and changes in ICA (r = - ۰.۰۲; P = ۰.۰۰۱). However, no significant correlations were observed between the changes in IOP and patient age (r = + ۰.۰۰۱; P = ۰.۹۵۷) and axial length of the eye (r = + ۰.۱۳; P = ۰.۲۲۱), or changes in ICA (r = - ۰.۰۱; P = ۰.۹۴۵), ACD (r = + ۰.۰۱; P = ۰.۹۴۵), and ACV (r = - ۰.۱۲; P = ۰.۵۹۹). Conclusions: We observed a significant reduction in IOP, widening of the ICA, and increases in ACD and ACV after phacoemulsification; however, there was no significant correlation between changes in IOP and other biometric variables. Further studies are required to determine the exact mechanisms underlying these effects.