Systematic Review and Meta-Analysis of Clinical Outcomes of Penetrating Keratoplasty Versus Deep Anterior Lamellar Keratoplasty for Keratoconus

Abstract

Objectives: In recent years, there have been rapid advances in the field of keratoconus. Penetrating keratoplasty and deep anterior lamellar keratoplasty are the standard surgical procedures. Nevertheless, controversy remains regarding the outcomes of both procedures in the treatment of keratoconus. Therefore, we conducted a meta-analysis comparing postoperative outcome measures of penetrating keratoplasty versus deep anterior lamellar keratoplasty for keratoconus.

Materials and methods: We searched PubMed, Embase, Web of Science, and the Cochrane Database of Systematic Reviews for eligible studies comparing best-corrected visual acuity, spherical equivalent, refractive cylinder, topography cylinder, and graft rejection episodes and complications of penetrating keratoplasty and deep anterior lamellar keratoplasty. Seven risk domains from software Review Manager 5.3 (The Cochrane Collaboration, Oxford, UK) were applied as quality assessments for the eligible studies. A random-effects model was used for data synthesis.

Results: Thirteen eligible studies were included in our meta-analysis, which encompassed 530 eyes that underwent penetrating keratoplasty and 568 eyes that underwent deep anterior lamellar keratoplasty. With regard to best-corrected visual acuity, refractive cylinder, and topography cylinder, we found no significant differences in results between the 2 procedures (P = .49 and .47, respectively). However, spherical equivalent results were significantly greater in the deep anterior lamellar keratoplasty group than in the penetrating keratoplasty group (P < .001). The risk of graft rejection episodes was more prominent in the penetrating keratoplasty than in the deep anterior lamellar keratoplasty group (odds ratio = 2.69; P = .001). The odds ratio for complications was 1.79 (P = .03). Three studies showed moderate risk of bias, and the other 10 showed high risk of bias.

Conclusions: Deep anterior lamellar keratoplasty is preferred over penetrating keratoplasty for the treatment of keratoconus because of its low risk of rejection and complications.