title: Outcomes of deep anterior lamellar keratoplasty following successful and failed 'big bubble'.
abstract: OBJECTIVE
  The most popular technique for deep anterior lamellar keratoplasty (DALK) is the 'big bubble' (BB) technique wherein air is injected in the cornea to create a bubble that separates Descemet's membrane (DM) from the stroma. An attempt to create a BB often results in the cornea being filled with numerous small bubbles without the formation of a BB. Manual dissection is then required to complete the procedure. The aim of the study is to compare these two groups, successful BB versus failed bubble (FB) dissection to determine whether the clinical outcomes were different.
  
  
  METHODS
  In this retrospective comparative study, 46 patients out of 52 who underwent DALK for various corneal stromal diseases such as keratoconus, stromal dystrophy or corneal scarring (caused by different conditions) were included in the analysis. BB was achieved in 25 patients and in the remaining 21 patients a BB separation of the DM was not possible necessitating manual lamellar dissection of stroma to get as close to the DM as possible.
  
  
  RESULTS
  The authors compared best-corrected visual acuity, contrast sensitivity, astigmatism, interface densitometry and Scheimpflug pachymetry in the two groups. Postoperative corneal thickness was higher in the 'small bubbles' group (mean 628.9 vs 564.1 μm; p<0.0005), but there was no significant difference in best-corrected visual acuity, astigmatism, contrast sensitivity and densitometry between the groups.
  
  
  CONCLUSIONS
  In DALK, manual lamellar dissection is a reasonable alternative when BB separation of the DM is not achieved.
authors: Department of Ophthalmology, Queens Medical Centre, Nottingham, UK.
authors: Uday K
authors: UK
authors: Bhatt
authors: Usama
authors: U
authors: Fares
authors: Imran
authors: I
authors: Rahman
authors: Dalia G
authors: DG
authors: Said
authors: Senthil V
authors: SV
authors: Maharajan
authors: Harminder S
authors: HS
authors: Dua
mesh_terms: D000328:Adult; D000867:Anterior Chamber / Q000601:surgery*; D002921:Cicatrix / Q000601:surgery; D003316:Corneal Diseases / Q000601:surgery; D003319:Corneal Stroma / Q000601:surgery*; D016039:Corneal Transplantation / Q000379:methods*; D003886:Descemet Membrane / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D016896:Treatment Outcome; D014792:Visual Acuity