title: Natural history of central islands after laser in situ keratomileusis.
abstract: OBJECTIVE
  To assess the incidence and natural history of central islands following laser in situ keratomileusis (LASIK) and evaluate the association of central island characteristics with visual acuity.
  
  
  METHODS
  Department of Ophthalmology, China Medical College Hospital, Taichung, Taiwan.
  
  
  METHODS
  A consecutive series of 406 eyes of 212 patients who had LASIK was retrospectively evaluated. Uncorrected visual acuity (UCVA) was measured and corneal topography performed preoperatively and 1 week and 1, 3, 6, and 9 months postoperatively. Best spectacle-corrected visual acuity (BSCVA) was evaluated preoperatively and 1, 3, and 6 months postoperatively.
  
  
  RESULTS
  The topographic images obtained at 1 week demonstrated central islands in 23 eyes of 20 patients (5.7%). No new cases of central island formation were identified after 1 week. Of the 23 eyes with central islands, the 6 month post-LASIK maps were available in 20 eyes of 18 patients. There was a significant difference in the size and power of the central islands between 1 week and 6 months. However, the power and size decreased slowly. Within 6 months, only 5 of 20 central islands (25.0%) had resolved. Eight eyes were undercorrected, and 1 eye lost 2 lines of BSCVA. Central islands larger than 1.8 mm or 3.0 diopters (D) were significantly correlated with lower UCVA.
  
  
  CONCLUSIONS
  Most central islands that occur with LASIK persist more than 6 months. Large central islands (>/=1.8 mm or >/=3.0 D) are risk factors for lower UCVA. Preventive measures are necessary.
authors.affiliation: Department of Ophthalmology, China Medical College Hospital, (Tsai), Taichung, Taiwan.
authors.forename: Y Y
authors.initials: YY
authors.lastname: Tsai
authors.forename: J M
authors.initials: JM
authors.lastname: Lin
mesh_terms: D000328:Adult; D001251:Astigmatism / Q000601:surgery; D002681:China / Q000453:epidemiology; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D003316:Corneal Diseases / Q000453:epidemiology / Q000209:etiology / Q000473:pathology*; D019781:Corneal Topography; D006801:Humans; D015994:Incidence; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D008875:Middle Aged; D009216:Myopia / Q000601:surgery; D012189:Retrospective Studies; D014792:Visual Acuity