Clinical outcomes after deep anterior lamellar keratoplasty using the big-bubble technique in patients with keratoconus

PURPOSE: To report clinical outcomes of deep anterior lamellar keratoplasty (DALK) using the big,bubble technique in patients with keratoconus. DESIGN : Prospective noncomparative interventional study. METHODS: SETTING: Single hospital. PATIENTS: Eighty, one unselected consecutive patients with moderate to advanced keratoconus intolerant to contact lenses and with poor spectacle corrected visual acuity. INTERVENTION: DALK big-bubble technique. MAIN OUTCOME MEASURES: Intraoperative and postoperative complications, postoperative uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest re fraction, corneal topography, and endothelial cell density. RESULTS: Seventy-eight procedures (96%) were completed as DALK. Big-bubble was achieved in 50 cases (64%); 28 (36%) required manual intrastromal dissection. Intraoperative microperforations occurred in 11 cases (13%). Baseline mean uncorrected visual acuity was 20/500 and 20/60 two years after surgery. Average preoperative BSCVA, was 20/100 and 20/30 at the end of follow-up. Final BSCVA was better in patients in whom bi-bubble with exposure of the Descemet membrane was achieved (P < .05). Average keratometry and SD (standard deviation) refraction changed from 62.1 +/- 6.7 diopters and -10.76 +/- 5 diopters to 47.51 +/- 4.73 diopters and -1.81 +/- 3.2 diopters, respectively after surgery. Mean preoperative endothelial cell density was 2202.29 +/- 392.35 cells/mm(2) and 2034 +/- 438.39 cells/mm(2) two years after surgery. Two patients developed stromal rejection. CONCLUSIONS: The DALK big,bubble technique is a valuable treatment in patients with keratoconus. Visual outcome is comparable to standard penetrating kerato, plasty (PK) when formation of big-bubble with exposure of the Descemet membrane (DM) was achieved. Clinically important graft,host interface developed in some cases after manual intrastromal dissection. Stromal rejection is a rare complication.