title: Refractive lens exchange in keratoconus.
abstract: OBJECTIVE
  To evaluate the visual results and complications of refractive lens exchange to correct myopia associated with early-stage keratoconus.
  
  
  METHODS
  Private practice, Siena, Italy.
  
  
  METHODS
  This prospective noncomparative interventional series comprised 34 consecutive eyes of 20 patients with stages I to II keratoconus. Mean patient age was 56.7 years +/- 10.4 (SD). Preoperative mean spherical equivalent (SE) was -11.0 +/- 4.65 diopters (D), (range -5.75 to -22). Ultrasound biometry was performed using videokeratographic central K-readings and the Holladay 2 formula. An intraoperative handheld autorefractor was used to check the power of implanted intraocular lenses.
  
  
  RESULTS
  Intraocular lens exchange due to inaccurate power occurred in 11 eyes (32%; 9 eyes intraoperative, 2 eyes postoperative). At 12 months, mean SE was -1.31 +/-1.08 D and mean defocus equivalent was 1.94 +/- 1.57 D. Twenty-two eyes (65%) were within +/-2 D of defocus equivalent, 16 eyes (47%) were within +/-1 D, and 3 eyes (9%) were within +/-0.5. Mean surgically induced astigmatism (vector analysis) was 0.54 +/- 0.43 D. Preoperative mean best spectacle-corrected visual acuity (BSCVA) was 0.55 +/- 0.20, and postoperative mean BSCVA was 0.76 +/- 0.23; the difference was statistically significant (P<.05; 95% confidence interval, 0.19 to 0.25). Postoperative mean uncorrected visual acuity was 0.48 +/- 0.25. The safety index was 1.38, and the efficacy index was 0.87. Complications were posterior vitreous detachment (9%) and dysphotopsia phenomena (15%). Corneal endothelial cell density at 12 months decreased by 6.3%.
  
  
  CONCLUSIONS
  Refractive lens exchange in keratoconic eyes predictably corrected myopia. However, ultrasound biometry was inaccurate in almost one third of eyes. Intraoperative autorefractometry is recommended to improve refractive outcome.
authors.affiliation: Ophthalmic Surgery Unit, Casa di Cura Rugani, Siena, Italy. leccisotti@libero.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Leccisotti
mesh_terms: D000368:Aged; D003315:Cornea / Q000000981:diagnostic imaging / Q000503:physiopathology; D019781:Corneal Topography; D005260:Female; D006801:Humans; D007640:Keratoconus / Q000150:complications* / Q000503:physiopathology; D019654:Lens Implantation, Intraocular / Q000379:methods*; D007910:Lenses, Intraocular; D008297:Male; D033401:Microscopy, Acoustic; D008875:Middle Aged; D009216:Myopia / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D011446:Prospective Studies; D012029:Refraction, Ocular; D012086:Reoperation; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology