title: Deep anterior lamellar keratoplasty versus penetrating keratoplasty for keratoconus: a clinical trial.
abstract: OBJECTIVE
  To compare deep anterior lamellar keratoplasty (DALK) using the big-bubble technique to penetrating keratoplasty (PK) in patients with keratoconus.
  
  
  METHODS
  In this clinical trial, patients with moderate to advanced keratoconus with poor spectacle-corrected visual acuity and intolerant to contact lens wear were enrolled. DALK was performed using the big-bubble technique, and a full-thickness donor cornea without Descemet membrane was sutured to the recipient bed. PK was performed conventionally with a Hessburg-Barron suction trephine. Three types of suturing were used for both groups. Postoperative refractive errors, best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and higher order aberrations (HOAs) were compared between the study groups.
  
  
  RESULTS
  The study included 81 eyes of 81 patients. Forty-six eyes underwent DALK from which 4 were excluded because of failure to achieve bared Descemet membrane. Thirty-five eyes received PK. Mean patient age was 26.91 ± 7.9 versus 30.89 ± 10.3 years in the DALK and PK groups, respectively (P = 0.06). Mean follow-up period was 22.0 ± 7.9 months in the DALK group and 24.6 ± 3.5 months in the PK group (P = 0.32). Mean postoperative spherical equivalent refractive error was -3.23 ± 3.4 diopters in the DALK group versus -2.22 ± 4.6 diopters in the PK group (P = 0.28), and mean postoperative BCVA was 0.18 ± 0.08 and 0.15 ± 0.10 logarithm of the minimum angle of resolution, respectively (P = 0.12). CSF and total aberrations and HOAs were comparable in the study groups.
  
  
  CONCLUSIONS
  DALK is an effective alternative surgical procedure for patients with keratoconus; the outcomes are comparable to PK in terms of refractive errors, BCVA, CSF, and HOAs.
authors.affiliation: Ophthalmic Research Center and Department of Ophthalmology, Labbafinejad Medical Center, Shahid Beheshti University, Boostan 9 St., Pasdaran Avenue, Tehran, Iran. ma_javadi@yahoo.com
authors.forename: Mohammad Ali
authors.initials: MA
authors.lastname: Javadi
authors.forename: Sepehr
authors.initials: S
authors.lastname: Feizi
authors.forename: Shahin
authors.initials: S
authors.lastname: Yazdani
authors.forename: Firooz
authors.initials: F
authors.lastname: Mirbabaee
mesh_terms: D057128:Aberrometry; D000293:Adolescent; D000328:Adult; D015350:Contrast Sensitivity / Q000502:physiology; D016039:Corneal Transplantation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D015948:Keratoplasty, Penetrating; D008297:Male; D008875:Middle Aged; D012029:Refraction, Ocular / Q000502:physiology; D012030:Refractive Errors / Q000503:physiopathology; D013536:Suture Techniques; D016896:Treatment Outcome; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult