title: Visual quality after posterior chamber phakic intraocular lens implantation in keratoconus.
abstract: OBJECTIVE
  To quantify image-quality characteristics after correction of refractive error with a posterior chamber phakic intraocular lens (PC pIOL) in eyes with stable or stabilized keratoconus.
  
  
  METHODS
  Narayana Nethralaya Postgraduate Institute of Ophthalmology, Bangalore, India.
  
  
  METHODS
  Case series.
  
  
  METHODS
  Eyes with stable or stabilized keratoconus that had V4 Visian PC pIOL implantation for correction of refractive error were evaluated postoperatively for visual-quality metrics.
  
  
  RESULTS
  Ten eyes of 7 patients had PC pIOL implantation. The preoperative mean refractive spherical equivalent of -7.21 diopters (D) ± 2.25 (SD) decreased to -0.55 ± 1.53 D at 6 weeks and -0.44 ± 1.21 D at 6 months. The efficacy index was 0.72 and the safety index, 1.13. The mean modulation transfer function (MTF) was 18.96 ± 14.16 (≥ 30 cycles per degree = good), the Strehl ratio was 0.11 ± 0.07 (1 = perfect), and the objective scatter index (OSI) was 4.45 ± 3.29 (≥ 1.5 = significant scatter). The MTF correlated inversely with secondary coma (P=.026), negative vertical coma (P=.014), and the root mean square (RMS) of total aberrations (P=.010) and higher-order aberrations (HOAs) (P=.015). The OSI was directly correlated with secondary coma (P=.021), secondary trefoil (P=.016), the RMS of total aberrations (P=.032), and HOAs (P=.050).
  
  
  CONCLUSIONS
  In keratoconus, the refractive error could be corrected with the PC pIOL; however, the associated aberrations had an adverse impact on the ultimate visual quality and have to be addressed.
authors.affiliation: Narayana Nethralaya, Post-Graduate Institute of Ophthalmology, Bangalore, India. dr.mkurian@gmail.com
authors.forename: Mathew
authors.initials: M
authors.lastname: Kurian
authors.forename: Somshekar
authors.initials: S
authors.lastname: Nagappa
authors.forename: Ridhima
authors.initials: R
authors.lastname: Bhagali
authors.forename: Rohit
authors.initials: R
authors.lastname: Shetty
authors.forename: Bhujang K
authors.initials: BK
authors.lastname: Shetty
mesh_terms: D057128:Aberrometry; D000328:Adult; D057108:Corneal Wavefront Aberration / Q000503:physiopathology; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000503:physiopathology / Q000601:surgery*; D019654:Lens Implantation, Intraocular; D008297:Male; D009216:Myopia / Q000503:physiopathology / Q000601:surgery*; D054120:Phakic Intraocular Lenses; D057972:Posterior Eye Segment / Q000601:surgery*; D011446:Prospective Studies; D012029:Refraction, Ocular / Q000502:physiology; D014792:Visual Acuity / Q000502:physiology*