title: Rigid gas-permeable contact lenses and severe higher-order aberrations in postsurgical corneas.
abstract: OBJECTIVE
  Even in the absence of significant residual refractive error, patients can be highly symptomatic after corneal refractive surgery. The presence of glare, halos, monocular polyopia, and loss of contrast are principally caused by the presence of higher-order aberrations. This study investigated the efficacy of rigid gas-permeable contact lenses in reducing these higher-order aberrations.
  
  
  METHODS
  In a prospective study, 20 eyes of 10 consecutive, highly symptomatic patients who had undergone refractive surgery were fitted with semiscleral rigid gas-permeable lenses (Macrolenses). The most successful lens design for each patient was evaluated by using ray-tracing aberrometry (iTrace).
  
  
  RESULTS
  The cohort had a mean uncorrected visual acuity of 20/30 and a mean best spectacle-corrected visual acuity of 20/25. The mean visual acuity with the treatment lenses was 20/20. The contact lenses reduced the combined higher-order aberrations by a mean of 65% (range, 30%-77%), combined coma by 71% (range, 39%-93%), spherical aberration by 82% (range, 41%-100%), and trefoil by 44% (range, 90% reduction to 727% increase). Multiple linear regression showed a high correlation with preoperative levels of myopia and mesopic pupil area as independent variables and postoperative spherical aberration as the dependent variable (R(2) = 0.82, SE = 0.09, F = 31.08, P<0.0001).
  
  
  CONCLUSIONS
  Rigid gas-permeable contact lenses were shown to reduce elevated total higher order aberrations to normal levels in all cases following corneal refractive surgery. The mean reduction was 66% for total higher order aberrations and 83% for spherical aberration. Correlation was shown between high preoperative refractive error and pupil size in relation to postoperative spherical aberration.
authors.affiliation: 712 South Denton Tap Road, Coppell, TX 75019, USA. greggem@verizon.net
authors.forename: Greg
authors.initials: G
authors.lastname: Gemoules
authors.forename: Kim M
authors.initials: KM
authors.lastname: Morris
mesh_terms: D000328:Adult; D015331:Cohort Studies; D003261:Contact Lenses; D019781:Corneal Topography; D003941:Diagnostic Techniques, Ophthalmological; D005260:Female; D005740:Gases; D006801:Humans; D007498:Iris / Q000473:pathology; D020731:Keratomileusis, Laser In Situ / Q000009:adverse effects*; D054018:Lasers, Excimer; D008297:Male; D008875:Middle Aged; D009216:Myopia / Q000601:surgery / Q000628:therapy; D010539:Permeability; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D011446:Prospective Studies; D014786:Vision Disorders / Q000175:diagnosis* / Q000209:etiology / Q000473:pathology / Q000628:therapy*; D014792:Visual Acuity
chemical_list: D005740:Gases