title: Deep Anterior Lamellar Keratoplasty Versus Penetrating Keratoplasty: A Meta-Analysis of Randomized Controlled Trials.
abstract: OBJECTIVE
  To evaluate the efficacy and safety of deep anterior lamellar keratoplasty (DALK) compared with penetrating keratoplasty (PK) for patients who had corneal stromal pathologies without endothelial abnormalities.
  
  
  METHODS
  We performed a meta-analysis using databases including PUBMED, EMBASE, and ClinicalTrials.gov to find relevant randomized controlled trials. Efficacy parameters were the postoperative best-corrected visual acuity, uncorrected visual acuity, and refractive error. Safety parameters were postoperative endothelial cell loss and graft rejection.
  
  
  RESULTS
  Five randomized controlled trials were selected for this meta-analysis, including 409 eyes (217 eyes in the DALK group and 192 eyes in the PK group). Postoperative logarithm of the minimum angle of resolution BCVA and UCVA were significantly better for PK than that for DALK [weighted mean difference (WMD) = 0.04, 95% confidence interval (CI), 0.01-0.07, P = 0.005 and WMD = 0.12, 95% CI, 0.05-0.18, P = 0.0007, respectively], whereas, the proportion of patients whose postoperative best-corrected visual acuity ≥ 20/40 did not differ statistically [risk ratio (RR) = 0.97, 95% CI, 0.89-1.07, P = 0.57]. There were no significant differences in terms of refractive error either by spherical equivalent or astigmatism (P = 0.11 and P = 0.25, respectively). The endothelial cell loss percentage in the PK group was significantly higher compared with the DALK group (WMD = -8.75, 95% CI, -15.25 to -2.25, P = 0.008). The DALK group was associated with a significantly lower frequency of graft rejection and endothelial rejection than the PK group (RR = 0.48, 95% CI, 0.28-0.82, P = 0.007 and RR = 0.07, 95% CI, 0.01-0.35, P = 0.001, respectively).
  
  
  CONCLUSIONS
  DALK is an alternative surgical procedure for corneal stromal pathologies without endothelial abnormalities, with lower efficacy but better safety.
authors.affiliation: *Department of Ophthalmology, Quzhou People's Hospital, Quzhou, Zhejiang, China; †The Roskamp Institute, Sarasota, FL; ‡Department of Ophthalmology, University of South Florida, Tampa, FL; and §Xiamen Eye Center of Xiamen University, Xiamen, Fujian, China.
authors.forename: Guohai
authors.initials: G
authors.lastname: Chen
authors.forename: Radouil
authors.initials: R
authors.lastname: Tzekov
authors.forename: Wensheng
authors.initials: W
authors.lastname: Li
authors.forename: Fangzheng
authors.initials: F
authors.lastname: Jiang
authors.forename: Sihong
authors.initials: S
authors.lastname: Mao
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Tong
mesh_terms: D003316:Corneal Diseases / Q000473:pathology / Q000601:surgery*; D003319:Corneal Stroma / Q000473:pathology; D016039:Corneal Transplantation / Q000379:methods*; D006801:Humans; D015948:Keratoplasty, Penetrating / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D014792:Visual Acuity / Q000502:physiology