title: Modified big-bubble deep anterior lamellar keratoplasty using peripheral air injection.
abstract: OBJECTIVE
  To introduce a modification to big-bubble deep anterior lamellar keratoplasty (DALK) which can decrease the risk of Descemet membrane (DM) perforation during air injection.
  
  
  METHODS
  In Anwar's big-bubble technique, a 27-guage needle is inserted from the trephination site and advanced into the corneal stroma up to the centre. The technique we introduce modifies the original technique in the following fashion. After trephination to approximately 80% of corneal thickness, a 27-guage needle is inserted into the stroma peripherally from the trephination site towards the limbus. Air is injected gently into the deep stroma until a big bubble is formed. This technique was performed in 16 consecutive keratoconic eyes undergoing DALK. Additionally, peripheral air injection was carried out in 27 eye-bank corneas using a peripheral approach.
  
  
  RESULTS
  In all (100%) eye-bank and 13 (81.3%) live corneas, a successful big bubble was easily achieved following peripheral air injection. In these 13 live corneas, all bubbles were formed at the central (n=10) or paracentral (n=3) cornea and extended centrifugally (type 1 bubble). In one of these corneas, an additional three bubbles were noted in the periphery between the DM and the pre-Descemet posterior stromal layer (Dua's layer, type 2) after a type 1 bubble was formed. In two live corneas in which peripheral air injection failed, a big bubble was successfully formed after air was injected inside the trephination site.
  
  
  CONCLUSIONS
  Air injection peripheral to the trephination site is a reproducible modification to the standard technique which can decrease the risk of DM perforation during air injection.
authors: Department of Ophthalmology, Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Sepehr
authors: S
authors: Feizi
authors: Department of Ophthalmology, Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Amir
authors: A
authors: Faramarzi
authors: Department of Ophthalmology, Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Mohammad Ali
authors: MA
authors: Javadi
authors: Department of Ophthalmology, Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
authors: Mohammad Reza
authors: MR
authors: Jafarinasab
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000388:Air; D002648:Child; D063171:Corneal Pachymetry; D003319:Corneal Stroma / Q000601:surgery*; D016039:Corneal Transplantation / Q000379:methods*; D003886:Descemet Membrane / Q000293:injuries*; D005260:Female; D006801:Humans; D056965:Injections, Intraocular; D007431:Intraoperative Complications / Q000517:prevention & control*; D007640:Keratoconus / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D014019:Tissue Donors
keywords: Cornea; Dystrophy; Experimental &#8211 laboratory; Treatment Surgery