title: Randomized Trial Comparing Amniotic Membrane Transplantation with Lamellar Corneal Graft for the Treatment of Corneal Thinning.
abstract: OBJECTIVE
  There are few studies comparing different surgical procedures for the treatment of corneal thinning. Lamellar corneal transplantation (LCT) has been reported to be efficient, but its results can be jeopardized by allograft rejection, opacification, or high astigmatism. Amniotic membrane transplantation (AMT) has been considered a good alternative, but it is not as resistant as LCT and the tissue can be reabsorbed after surgery.
  
  
  METHODS
  A prospective, randomized, interventional, and comparative study of consecutive patients with corneal thinning over 6 months was performed. Ophthalmological examination was performed before transplant surgery and then repeated 1, 7, 15, 30, 90, and 180 days after surgery and ultrasound biomicroscopy was performed before and then 30, 90, and 180 days after surgery to assess corneal thinning.
  
  
  RESULTS
  Herpes simplex infection was the main cause of corneal thinning (9 eyes), followed by surgery (cataract, glaucoma, 5 cases), rheumatoid arthritis (1), chemical burn (1), perforating trauma (1), previous band keratopathy treatment (1), and Stevens-Johnson syndrome (1). Although all patients showed significant increase in final thickness in the area of thinning, it was higher in those submitted to LCT at 180 days postoperatively. Regardless of the surgical technique, all patients showed epithelialization. Patients undergoing AMT showed an 89% decrease in neovascularization. Final corrected distance visual acuity was better in patients submitted to AMT.
  
  
  CONCLUSIONS
  LCT proved to be the best option for treating corneal thinning. AMT represents an alternative that allows good visual recovery but does not restore corneal thickness as efficiently as LCT.
authors.affiliation: *Ocular Surface Advanced Center (CASO); †Cornea and External Disease Unit; and ‡Ocular Ultrasound Unit, Department of Ophthalmology and Visual Sciences, Federal University of São Paulo (UNIFESP), São Paulo, Brazil.
authors.forename: Charles C
authors.initials: CC
authors.lastname: de Farias
authors.forename: Norma
authors.initials: N
authors.lastname: Allemann
authors.forename: José Á P
authors.initials: JÁ
authors.lastname: Gomes
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000650:Amnion / Q000637:transplantation*; D003315:Cornea / Q000473:pathology*; D003316:Corneal Diseases / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D063171:Corneal Pachymetry; D016039:Corneal Transplantation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011184:Postoperative Period; D011446:Prospective Studies; D014792:Visual Acuity / Q000502:physiology