title: Comparison of visual and topographic outcomes of deep-anterior lamellar keratoplasty and penetrating keratoplasty in keratoconus.
abstract: OBJECTIVE
  To compare visual, surgical and topographic outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) for keratoconus (KC).
  
  
  METHODS
  In this multicenter, prospective, randomized clinical trial 76 eyes of 71 KC patients operated between January 2011 and July 2014 in 2 tertiary referral hospitals were included. Consecutive patients were alternately selected to receive one of the two surgical methods. Thirty eight eyes underwent DALK with the big-bubble technique and 38 eyes underwent PK.
  
  
  RESULTS
  Mean best spectacle corrected visual acuity (BSCVA) at the first postoperative week (P=0.012) and the first postoperative month (P<0.001) was statistically significantly higher in DALK group. The mean BSCVA at 12mo was not significantly different for DALK (0.30±1.99 logMAR) versus PK (0.40±0.33 logMAR) (P=0.104). The 76.3% of the eyes had a BSCVA over 0.5 in DALK and 47.4% in PK group (P=0.009). The 7.9% of the eyes had a BSCVA of 1.0 in DALK and 5.3% in PK group (P=0.644). Mean spherical equivalent was -2.94 D in DALK and -3.09 D in PK group. Mean topographic astigmatism was 4.62 D and 4.18 D respectively. Regular topographic patterns were observed in 31 (81.6%) of DALK and 29 (76.3%) of PK (P=0.574). The most frequent topographic pattern was oblate asymmetric bow tie, seen in 39.5% in DALK and 23.7% in PK.
  
  
  CONCLUSIONS
  Big bubble DALK provides an earlier visual improvement compare to PK. However, visual and topographic outcomes are similar to those in PK at 1y. Postoperative complications including rejection and intraocular pressure elevation are more frequent in PK. DALK is a safer alternative to PK for KC. However, intraoperative perforation of the Descemet's membrane is a significant complication.
authors.affiliation: Department of Ophthalmology, Izmir Bozyaka Training and Research Hospital, Izmir 35110, Turkey.
authors.forename: Bora
authors.initials: B
authors.lastname: Yüksel
authors.affiliation: Department of Ophthalmology, Kartal Training and Research Hospital, Istanbul 34660, Turkey.
authors.forename: Baran
authors.initials: B
authors.lastname: Kandemir
authors.affiliation: Department of Ophthalmology, Izmir Bozyaka Training and Research Hospital, Izmir 35110, Turkey.
authors.forename: Umut Duygu
authors.initials: UD
authors.lastname: Uzunel
authors.affiliation: Department of Ophthalmology, Izmir Bozyaka Training and Research Hospital, Izmir 35110, Turkey.
authors.forename: Ozan
authors.initials: O
authors.lastname: Çelik
authors.affiliation: Department of Ophthalmology, Kartal Training and Research Hospital, Istanbul 34660, Turkey.
authors.forename: Sezgin
authors.initials: S
authors.lastname: Ceylan
authors.affiliation: Department of Ophthalmology, Izmir Bozyaka Training and Research Hospital, Izmir 35110, Turkey.
authors.forename: Tuncay
authors.initials: T
authors.lastname: Küsbeci
keywords: deep anterior lamellar keratoplasty; keratoconus; penetrating keratoplasty