AIM: To investigate how angles kappa and alpha affect postoperative visual quality in patients with multifocal intraocular lens(mIOLs)implantation.

METHODS: Retrospective cases series. A total of 46 patients(46 eyes)who underwent phacoemulsification were subsumed. The correlation between Preoperative angles kappa and alpha, wave-front aberrations and objective visual quality of cornea, internal, and total eye after surgery were analyzed using iTrace.

RESULTS: The magnitude of angle kappa was negatively correlated with internal and total modulation transfer function(MTF)at 3 mm; the magnitude of angle kappa was positively correlated with astigmatism, trefoil, higher-order aberrations(HOAs)of both internal and total eye at 3 mm. The magnitude of angle alpha was negatively correlated with total MTF and total Strehl ratio at 3 mm. The magnitude of angle alpha was positively correlated with corneal coma at 5 mm, internal astigmatism at both 3 mm and 5 mm, and total spherical aberration(SA)at 3 mm. Multivariate linear regression analysis showed that, among candidate independent variables(kappa, alpha, astigmatism, SA, coma, trefoil, and HOAs), astigmatism is the only independent factor for altering corneal MTF at 3 mm and 5 mm; astigmatism and HOAs emerged as independent factors for altering internal MTF at 3 mm and 5 mm, and total MTF at 3 mm; astigmatism, SA and HOAs emerged as independent factors for altering total MTF at 5 mm.

CONCLUSION: With greater preoperative angle kappa or angle alpha, patients who accept mIOL implantation tend to have larger internal astigmatism and HOAs, which resulting in poor visual quality, especially those with small pupil size.