title: Predictive factors for photic phenomena after refractive, rotationally asymmetric, multifocal intraocular lens implantation.
abstract: OBJECTIVE
  To investigate the independent factors associated with photic phenomena in patients implanted with refractive, rotationally asymmetric, multifocal intraocular lenses (MIOLs).
  
  
  METHODS
  Thirty-four eyes of 34 patients who underwent unilateral cataract surgery, followed by implantation of rotationally asymmetric MIOLs were included. Distance and near visual acuity outcomes, intraocular aberrations, preferred reading distances, preoperative and postoperative refractive errors, mesopic and photopic pupil diameters, and the mesopic and photopic kappa angles were assessed. Patients were also administered a satisfaction survey. Photic phenomena were graded by questionnaire. Independent-related factors were identified by correlation and bivariate logistic regression analyses.
  
  
  RESULTS
  The distance from the photopic to the mesopic pupil center (pupil center shift) was significantly associated with glare/halo symptoms [odds ratio (OR)=2.065, 95% confidence interval (CI)=0.916-4.679,P=0.006] and night vision problems (OR=1.832, 95% CI=0.721-2.158,P=0.007). The preoperative photopic angle kappa was significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362,P=0.041). The photopic angle kappa was also significantly associated with glare/halo symptoms (OR=2.155, 95% CI=1.065-4.362,P=0.041) and with night vision problems (OR=1.832, 95% CI=0.721-2.158,P=0.007) in patients implanted with rotationally asymmetric MIOLs.
  
  
  CONCLUSIONS
  A large pupil center shift and misalignment between the visual and pupillary axis (angle kappa) may play a role in the occurrence of photic phenomena after implantation of rotationally asymmetric MIOLs.
authors.affiliation: Department of Ophthalmology, Ulsan University College of Medicine, Asan Medical Center, Seoul 05505, Korea.
authors.forename: Hungwon
authors.initials: H
authors.lastname: Tchah
authors.affiliation: Department of Physical Medicine & Rehabilitation, Dongguk University College of Medicine, Goyang 10326, Korea.
authors.forename: Kiyeun
authors.initials: K
authors.lastname: Nam
authors.affiliation: Department of Ophthalmology, Saevit Eye Hospital, Goyang 10447, Korea.
authors.forename: Aeri
authors.initials: A
authors.lastname: Yoo
keywords: dysphotopsia; kappa angle; photic phenomena; pupil center; pupil center shift; rotationally asymmetric multifocal intraocular lens