title: Apical nodular subepithelial corneal scar after retreatment in hyperopic photorefractive keratectomy.
abstract: OBJECTIVE
  To report a complication, apical nodular subepithelial corneal scar, that can occur after hyperopic photorefractive keratectomy (PRK) retreatment.
  
  
  METHODS
  Istanbul University Eye Research Center, Istanbul, Turkey.
  
  
  METHODS
  Twelve eyes of 6 patients with apical nodular subepithelial corneal scar were retrospectively studied. Mean age of the 5 men and 1 woman was 30.2 years +/- 5.4 (SD). All eyes had hyperopic PRK retreatment for regression 9.5 +/- 1.44 months after primary hyperopic PRK. Mean spherical equivalent refraction of the residual hyperopia before retreatment was +4.67 +/- 0.81 diopters (D). All patients had a corneal haze grade of less than 1+. Hyperopic PRK retreatment was performed with a 193 nm excimer laser (Chiron Technolas Keracor 116).
  
  
  RESULTS
  Apical nodular subepithelial corneal scars developed within the first month of hyperopic PRK retreatment and progressed until the third month in 12 eyes of 6 patients. The lesion was round and symmetrical in both eyes, smaller than 2.0 mm, and centrally located. During the mean 40.66 +/- 2.46 month follow-up, the lesion did not change in size or density. Mean spherical equivalent refraction after retreatment was 2.88 +/- 0.88 D (range +1.50 to +4.00 D) at 1 month and +4.36 +/- 1.83 D at last follow-up. Refraction was unmeasurable in 3 eyes. Five eyes lost 1 line of best spectacle-corrected visual acuity and 7 eyes, 2 or more lines. The surface regularity indexes were higher than 2.00 in all the eyes.
  
  
  CONCLUSIONS
  Hyperopic PRK retreatment may cause the sight-threatening complication of apical nodular subepithelial corneal scar. This complication behaves unlike corneal haze and does not resolve spontaneously over time.
authors.affiliation: Istanbul University Eye Research Center, Istanbul, Turkey.
authors.forename: B
authors.initials: B
authors.lastname: Sener
authors.forename: A
authors.initials: A
authors.lastname: Ozdamar
authors.forename: C
authors.initials: C
authors.lastname: Aras
mesh_terms: D000328:Adult; D002921:Cicatrix / Q000209:etiology* / Q000473:pathology; D003316:Corneal Diseases / Q000209:etiology* / Q000473:pathology; D019781:Corneal Topography; D019573:Epithelium, Corneal / Q000473:pathology*; D005260:Female; D006801:Humans; D006956:Hyperopia / Q000601:surgery*; D054018:Lasers, Excimer; D008297:Male; D018903:Photorefractive Keratectomy / Q000009:adverse effects*; D012029:Refraction, Ocular; D012086:Reoperation / Q000009:adverse effects; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity