Changes in angle kappa and angle alpha before and after cataract surgery

To observe the distributions and changes in angle kappa and angle alpha preoperatively and postoperatively in patients with cataract who were implanted with a multifocal intraocular lens (mIOL).The First Affiliated Hospital of Northwest University, Shaanxi, China.Prospective nonrandomized noncomparative case series.Eyes that underwent phacoemulsification were included. The magnitudes and orientations of angle kappa and angle alpha preoperatively and postoperatively were compared, respectively.The study comprised 81 eyes of 70 patients. The magnitude of angle kappa significantly decreased after phacoemulsification. No significant differences were observed between preoperative and postoperative angle kappa in orientation, as well as between preoperative and postoperative angle alpha. The correlations between preoperative and postoperative angle kappa and angle alpha were significant. There were displacement vectors for angle kappa (0.15 ± 0.10) and angle alpha (0.12 ± 0.12) after phacoemulsification. Locations of angle kappa of right and left eyes were scattered mostly in the temporal side of corneal light reflection, whereas locations of angle alpha were well organized in the horizontal position on temporal sides of corneal light reflection.The distribution of angle alpha was more organized compared with angle kappa. Angle kappa may change after phacoemulsification. During preoperative evaluation for patients with cataract planning for mIOLs implanted angle alpha may be a more reliable and stable factor compared with angle kappa.