title: Confocal microscopy after implantation of intrastromal corneal ring segments.
abstract: OBJECTIVE
  Confocal in vivo real-time microscopy was used to study the corneal morphologic features in eyes after Intrastromal Corneal Ring Segments (ICRS; now called KeraVision INTACS, KeraVision, Inc., Fremont, CA) implantation.
  
  
  METHODS
  Noncomparative, interventional case series.
  
  
  METHODS
  The authors performed confocal real-time microscopy on a total of 21 eyes from 11 patients. Seventeen eyes from 10 patients (five female, five male; mean age 32.3 years; range 22-42 years) underwent uncomplicated ICRS surgery to correct myopia and were examined after surgery (average 8.6 months; range 2-15 months). Three patients had the ICRS implanted into only one eye, and those eyes were compared with the untreated fellow eyes. One eye of another patient was examined 1 and 6 months after ICRS removal.
  
  
  METHODS
  Flying slit-confocal microscopy was performed with water immersion objectives in the corneal center and near the nasal or temporal ICRS. Corneal optical sections were recorded in real time without further digital processing and were reviewed frame by frame.
  
  
  METHODS
  Video frames selected from all corneal layers were evaluated qualitatively and quantitatively.
  
  
  RESULTS
  In the central cornea, we found normal morphologic features at all layers. In peripheral sections, epithelial cells with highly reflective nuclei in the basal cell layer were observed in six of 17 eyes (35%) implanted with ICRS. We found an intact corneal nerve plexus and undisturbed corneal endothelium immediately underneath the ICRS. Around the ICRS, moderate fibrosis was seen. In one eye, linear structures in bamboo-like orientation were detected after ICRS removal in the last keratocyte layer underneath the collapsed tunnel.
  
  
  CONCLUSIONS
  Whereas the central corneal zone appears unchanged, the corneal stroma adjacent to the ICRS displays a slight, but distinct, activation of wound healing. Epithelial cells with highly reflective nuclei in this region may be an indicator for an increased biologic stress caused by the device.
authors.affiliation: Landesklinik für Augenheilkunde und Optometrie, Salzburg, Austria. Department of Ophthalmology, University of Bern, Bern, Switzerland. j.ruckhofer@lks.at
authors.forename: J
authors.initials: J
authors.lastname: Ruckhofer
authors.forename: M
authors.initials: M
authors.lastname: Böhnke
authors.forename: E
authors.initials: E
authors.lastname: Alzner
authors.forename: G
authors.initials: G
authors.lastname: Grabner
mesh_terms: D000328:Adult; D001672:Biocompatible Materials; D003319:Corneal Stroma / Q000294:innervation / Q000473:pathology* / Q000601:surgery; D020878:Device Removal; D004847:Epithelial Cells / Q000473:pathology; D005260:Female; D005355:Fibrosis; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D009216:Myopia / Q000473:pathology* / Q000601:surgery; D019904:Polymethyl Methacrylate; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D014741:Video Recording; D014945:Wound Healing
chemical_list: D001672:Biocompatible Materials; D019904:Polymethyl Methacrylate