title: Confocal microscopy analysis of corneal changes after photorefractive keratectomy plus cross-linking for keratoconus: 4-year follow-up.
abstract: OBJECTIVE
  To analyze corneal confocal microscopy changes after combined photorefractive keratectomy (PRK) plus the cross linking (CXL) procedure.
  
  
  METHODS
  Prospective interventional case series.
  
  
  METHODS
  At the Department of Basic Medical Sciences, Neuroscience, and Sense Organs of the University of Bari, Bari, Italy, 17 eyes of 17 patients with progressive keratoconus underwent confocal microscopy examination before and after 1, 3, 6, 12, 18, and 48 months following PRK plus the CXL procedure. The main outcome measures were mean superficial epithelial cell density; mean basal epithelial cell density; mean anterior, mid and posterior keratocyte density; qualitative analysis of stromal backscatter; sub-basal and stromal nerve density parameters; and mean endothelial cell density.
  
  
  RESULTS
  During the 4-year follow-up, the mean superficial epithelial cell density, mean basal epithelial cell density and mean endothelial cell density remained unchanged (P > 0.05). The anterior mid-stromal keratocyte density showed a significant decrease (P < 0.05) as compared with preoperative values, and the posterior stromal keratocyte density showed a significant increase at 1 and 3 months of follow-up. Sub-basal and stromal nerve density parameters were significantly decreased until postoperative month 6 (P < 0.05 at 1, 3, and 6 months) and then tended to increase up to preoperative values by the 18th postoperative month.
  
  
  CONCLUSIONS
  Corneal changes after the PRK plus CXL procedures seem to be pronounced and long lasting as far as keratocyte density of the anterior and mid stroma is concerned. Sub-basal nerve densities tend to reach preoperative values 6 months after surgery.
authors.affiliation: Clinica Oculistica, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, University of Bari, Bari, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Alessio
authors.affiliation: Clinica Oculistica, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, University of Bari, Bari, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: L'Abbate
authors.affiliation: Clinica Oculistica, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, University of Bari, Bari, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Furino
authors.affiliation: Clinica Oculistica, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, University of Bari, Bari, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Sborgia
authors.affiliation: Clinica Oculistica, Department of Basic Medical Sciences, Neuroscience, and Sense Organs, University of Bari, Bari, Italy. Electronic address: mariagabriella.lategola@uniba.it.
authors.forename: Maria Gabriella
authors.initials: MG
authors.lastname: La Tegola
mesh_terms: D000328:Adult; D002452:Cell Count; D003094:Collagen / Q000378:metabolism*; D003315:Cornea / Q000473:pathology* / Q000601:surgery; D003319:Corneal Stroma / Q000473:pathology; D003432:Cross-Linking Reagents / Q000627:therapeutic use*; D019573:Epithelium, Corneal / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000473:pathology / Q000628:therapy*; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008875:Middle Aged; D010778:Photochemotherapy / Q000379:methods*; D018903:Photorefractive Keratectomy; D011184:Postoperative Period; D011446:Prospective Studies; D013997:Time Factors; D014466:Ultraviolet Rays; D055815:Young Adult
chemical_list: D003432:Cross-Linking Reagents; D003094:Collagen