title: Deep anterior lamellar keratoplasty as an alternative to penetrating keratoplasty a report by the american academy of ophthalmology.
abstract: OBJECTIVE
  To review the published literature on deep anterior lamellar keratoplasty (DALK) to compare DALK with penetrating keratoplasty (PK) for the outcomes of best spectacle-corrected visual acuity (BSCVA), refractive error, immune graft rejection, and graft survival.
  
  
  METHODS
  Searches of the peer-reviewed literature were conducted in the PubMed and the Cochrane Library databases. The searches were limited to citations starting in 1997, and the most recent search was in May 2009. The searches yielded 1024 citations in English-language journals. The abstracts of these articles were reviewed, and 162 articles were selected for possible clinical relevance, of which 55 were determined to be relevant to the assessment objective.
  
  
  RESULTS
  Eleven DALK/PK comparative studies (level II and level III evidence) were identified that compared the results of DALK and PK procedures directly; they included 481 DALK eyes and 501 PK eyes. Of those studies reporting vision and refractive data, there was no significant difference in BSCVA between the 2 groups in 9 of the studies. There was no significant difference in spheroequivalent refraction in 6 of the studies, nor was there a significant difference in postoperative astigmatism in 9 of the studies, although the range of astigmatism was often large for both groups. Endothelial cell density (ECD) stabilized within 6 months after surgery in DALK eyes. Endothelial cell density values were higher in the DALK groups in all studies at study completion, and, in general, the ECD differences between DALK and PK groups were significant at all time points at 6 months or longer after surgery for all of the studies reporting data.
  
  
  CONCLUSIONS
  On the basis of level II evidence in 1 study and level III evidence in 10 studies, DALK is equivalent to PK for the outcome measure of BSCVA, particularly if the surgical technique yields minimal residual host stromal thickness. There is no advantage to DALK for refractive error outcomes. Although improved graft survival in DALK has yet to be demonstrated, postoperative data indicate that DALK is superior to PK for preservation of ECD. Endothelial immune graft rejection cannot occur after DALK, which may simplify long-term management of DALK eyes compared with PK eyes. As an extraocular procedure, DALK has important theoretic safety advantages, and it is a good option for visual rehabilitation of corneal disease in patients whose endothelium is not compromised.
authors.affiliation: Department of Ophthalmology, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Reinhart
authors.forename: David C
authors.initials: DC
authors.lastname: Musch
authors.forename: Deborah S
authors.initials: DS
authors.lastname: Jacobs
authors.forename: W Barry
authors.initials: WB
authors.lastname: Lee
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Kaufman
authors.forename: Roni M
authors.initials: RM
authors.lastname: Shtein
mesh_terms: D000047:Academies and Institutes / Q000458:organization & administration; D002452:Cell Count; D003316:Corneal Diseases / Q000503:physiopathology / Q000534:rehabilitation; D016039:Corneal Transplantation; D016208:Databases, Factual; D004728:Endothelium, Corneal / Q000473:pathology; D006084:Graft Rejection / Q000503:physiopathology*; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D015948:Keratoplasty, Penetrating; D009885:Ophthalmology / Q000458:organization & administration; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology*; D013673:Technology Assessment, Biomedical; D016896:Treatment Outcome; D014481:United States; D014792:Visual Acuity / Q000502:physiology*