title: Keratorefractive effect of microwave keratoplasty on human corneas.
abstract: OBJECTIVE
  To determine the change in dioptric power on excised human corneoscleral buttons after microwave keratoplasty application and to determine the qualitative effect on the cornea using histology and scanning electron microscopy.
  
  
  METHODS
  Department of Academic Ophthalmology, Rayne Institute, St. Thomas' Hospital, London, United Kingdom.
  
  
  METHODS
  Excised human corneoscleral buttons were treated with a prototype microwave keratoplasty ring applicator. A 28.12 W, 1-second application was performed on the corneas using a 6.0 mm diameter inner conductor and an 8.4 mm diameter outer conductor. Videokeratography was performed with a topographic modeling system (TMS-1) before and after microwave keratoplasty. The induced change in corneal curvature was calculated using the mean dioptric power of rings situated 2.0 to 6.0 mm from the geometrical apex of the corneas. Scanning electron microscopy and toluidine-blue light microscopy were performed to determine the effect on the corneal stroma.
  
  
  RESULTS
  Six excised corneoscleral buttons from 6 donors were used. The mean reduction in curvature after microwave keratoplasty application was 3.07 diopters +/- 2.62 (SD). Scanning and light microscopy showed microwave-induced shrinkage of corneal stromal collagen with little disturbance to the overlying epithelium.
  
  
  CONCLUSIONS
  Microwave keratoplasty reduced corneal curvature and has therapeutic potential as a noninvasive alternative to excimer laser surgical correction of myopia and as a treatment for corneal ectasia.
authors.affiliation: Department of Academic Ophthalmology, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom. abarsam@hotmail.com
authors.forename: Allon
authors.initials: A
authors.lastname: Barsam
authors.forename: Anne
authors.initials: A
authors.lastname: Patmore
authors.forename: David
authors.initials: D
authors.lastname: Muller
authors.forename: John
authors.initials: J
authors.lastname: Marshall
mesh_terms: D000369:Aged, 80 and over; D000818:Animals; D003094:Collagen / Q000378:metabolism; D003315:Cornea / Q000378:metabolism / Q000601:surgery* / Q000648:ultrastructure; D019781:Corneal Topography; D004564:Electrocoagulation / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008872:Microwaves; D008954:Models, Biological; D011489:Protein Denaturation; D054140:Refractive Surgical Procedures / Q000379:methods*; D013552:Swine; D014019:Tissue Donors
chemical_list: D003094:Collagen