title: Influence of Near-Segment Positioning in a Rotationally Asymmetric Multifocal Intraocular Lens.
abstract: OBJECTIVE
  To compare visual performance and higher order aberrations (HOAs) based on the position of the near segment in eyes with rotationally asymmetric multifocal intraocular lenses (IOLs).
  
  
  METHODS
  Asymmetric multifocal IOLs (Lentis Mplus LS-313; Oculentis Optikgeräte GmbH, Wetzlar, Germany) were implanted with the near segment positioned either inferiorly, superiorly, or temporally. Uncorrected distance (UDVA), intermediate (UIVA), and near (UNVA) visual acuity, corrected distance visual acuity (CDVA), and distance-corrected intermediate (DCIVA) and near (DCNVA) visual acuity, contrast sensitivity, HOAs, and subjective symptom questionnaires were compared at 1 month postoperatively.
  
  
  RESULTS
  Forty-five eyes from 45 patients were evaluated (n = 25, 9, and 11 eyes in the inferior, superior, and temporal groups, respectively). No significant differences in UDVA, UIVA, UNVA, CDVA, DCIVA, or DCNVA were found between the three groups (P > .05). The temporal group showed the best results in UDVA, CDVA, and DCNVA, but the inferior group showed the best results in DCIVA and UNVA and the superior group showed the best results in UIVA. Contrast sensitivity and the subjective symptom questionnaire also did not demonstrate any significant differences (P > .05). Total HOA and spherical aberration did not demonstrate any statistically significant differences (P > .05), but vertical coma and horizontal coma demonstrated significant differences based on near segment position (P < .001).
  
  
  CONCLUSIONS
  The position of the near segment in eyes with rotationally asymmetric multifocal IOLs demonstrates no significant effect on visual performance.
authors.forename: In Seok
authors.initials: IS
authors.lastname: Song
authors.forename: Sam Young
authors.initials: SY
authors.lastname: Yoon
authors.forename: Jae Yong
authors.initials: JY
authors.lastname: Kim
authors.forename: Myoung Joon
authors.initials: MJ
authors.lastname: Kim
authors.forename: Hungwon
authors.initials: H
authors.lastname: Tchah
mesh_terms: D000368:Aged; D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D008875:Middle Aged; D055095:Optics and Photonics; D018918:Phacoemulsification; D011474:Prosthesis Design; D019591:Pseudophakia / Q000503:physiopathology*; D012029:Refraction, Ocular / Q000502:physiology; D012189:Retrospective Studies; D011795:Surveys and Questionnaires; D014792:Visual Acuity / Q000502:physiology*