title: Modified automated lamellar therapeutic keratoplasty for keratoconus: a new technique.
abstract: OBJECTIVE
  To describe a modified automated lamellar therapeutic keratoplasty (ALTK) technique for the treatment of keratoconus.
  
  
  METHODS
  The ALTK procedure was modified to include the use of a Hanna trephine system to control donor and recipient diameters and was performed in 2 stages. The recipient corneal lamellar bed was first prepared by creating a laser in situ keratomileusis (LASIK) flap at a preset depth that was left to heal over. The second stage involved the use of a Hanna trephination system to perform central trephination within the lamellar flap and transplantation of a donor lamellar graft that was fashioned to precisely match the recipient corneal bed, again using the Hanna donor punch to create a central trephination within the lamellar button obtained with the ALTK unit.
  
  
  RESULTS
  The modified ALTK procedure effectively treated a patient with moderate keratoconus with a best-corrected visual acuity of 20/80, despite rigid gas-permeable contact lenses. Postoperatively, there was a significant reduction in the irregular astigmatism, and visual acuity improved to 20/25. There were no complications, and the ALTK interface remained clear throughout the 20-month follow-up period.
  
  
  CONCLUSIONS
  ALTK combined with Hanna trephination enables precise control of both depth and diameter of lamellar dissection during surgery, removes the need for any form of manual dissection, and may therefore improve optical and visual outcomes in lamellar keratoplasty.
authors.affiliation: Singapore National Eye Centre, the Department of Ophthalmology, National University of Singapore, and the Singapore Eye Research Institute, Singapore. snecdt@pacific.net.sg
authors.forename: Donald T H
authors.initials: DT
authors.lastname: Tan
authors.forename: Leonard P K
authors.initials: LP
authors.lastname: Ang
mesh_terms: D000328:Adult; D003315:Cornea / Q000601:surgery*; D019781:Corneal Topography; D016039:Corneal Transplantation / Q000379:methods*; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D008297:Male; D014019:Tissue Donors; D014792:Visual Acuity / Q000502:physiology