Modified big-bubble technique compared to manual dissection deep anterior lamellar keratoplasty in the treatment of keratoconus

Karl Anders Knutsson, Paolo Rama, Giorgio Paganoni

Research output: Contribution to journalArticlepeer-review


Purpose To evaluate the clinical findings and results of manual dissection deep anterior lamellar keratoplasty (DALK) compared to a modified big-bubble DALK technique in eyes affected by keratoconus. Methods Sixty eyes of 60 patients with keratoconus were treated with one of the two surgical techniques manual DALK (n = 30); big-bubble DALK (n = 30). The main outcomes measured were visual acuity, corneal topographic parameters, thickness of residual stroma and endothelial cell density (ECD). Patients were examined postoperatively at 1 month, 6 months, 1 year and 1 month after suture removal. Results Final best spectacle-corrected visual acuity (BSCVA) measured 1 month after suture removal was 0.11 ± 0.08 LogMAR in the big-bubble group compared to 0.13 ± 0.08 in the manual DALK group (p = 0.227). In patients treated with the big-bubble technique without complications (Descemet's membrane completely bared), the stromal residue was not measureable. Mean stromal residual thickness in the manual DALK group was 30.50 ± 27.60 μm. Data analysis of the manual DALK group demonstrated a significant correlation between BSCVA and residual stromal thickness; lower residual stromal thickness correlated with better BSCVA values (Spearman ρ = 0.509, p = 0.018). Postoperative ECD was similar in both groups at all intervals, with no statistically significant differences. In both groups, ECD loss was only significant during the 1- to 6-month interval (p = 0.001 and p <0.001 in the big-bubble DALK and manual DALK groups, respectively). Conclusion Manual DALK provides comparable results to big-bubble DALK. Big-bubble DALK permits faster visual recovery and is a surgical technique, which can be easily converted to manual DALK in cases of unsuccessful 'big-bubble' formation.

Original languageEnglish
Pages (from-to)431-438
Number of pages8
JournalActa Ophthalmologica
Issue number5
Publication statusPublished - Aug 1 2015


  • big bubble
  • deep anterior lamellar keratoplasty
  • keratoconus
  • keratoplasty

ASJC Scopus subject areas

  • Ophthalmology


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