Changes in Chord Mu (µ) Length Before and After Cataract Surgery

Abstract

Aim: Comparison of chord  length, a potential marker that may gain importance especially in multifocal lens implantation, before and after phacoemulsification surgery and intraocular lens (IOL) implantation in patients with cataracts. Methods: This retrospective study included 33 eyes of 33 patients who underwent phacoemulsification surgery between December 2022 and February 2023. Corneal topography (Pentacam HR, Oculus, Wetzlar, optikgerate GmbH) was performed on each patient before and after surgery. The values obtained before and at least 3 months after surgery were compared using the Student-t test. Results: There were 18 (54.5%) males and 15 (45.5%) females among the 33 patients who participated in the study. The average age was 67.27 ± 10.93 years. The postoperative mean chord μ lenght was significantly lower than the preoperative mean chord μ lenght (p=0.002). Additionally, the mean postoperative pupil size was significantly lower than the mean preoperative pupil size (p=0.000). There is a weak positive relationship between the change in chord μ length and the change in pupil size, but this relationship is not statistically significant (p>0.05). No statistically significant relationship was found between any of the other binary variables. Conclusion: Centralization is crucial in refractive surgery and multifocal IOL implantation to prevent high-order aberrations and photic phenomena. Therefore, it seems useful for surgeons to be familiar with chord μ measurements, especially regarding surgical preparation. It should be considered that changes in chord mu values may influence the development of photic phenomena. A decrease in chord mu after phacoemulsification may assist the surgeon in the preoperative decision-making process in patients at risk of photic phenomena or in patients with borderline values.