Pneumatic Dissection for Large-Diameter (9-mm) Deep Anterior Lamellar Keratoplasty in Eyes With Previous Anterior Lamellar Keratoplasty

Purpose To evaluate the surgical and 3-year clinical outcomes of modified big-bubble 9-mm deep anterior lamellar keratoplasty (DALK) in eyes with previous ALK (ALK). Methods In this interventional case series, 21 consecutive eyes with unsatisfactory vision after ALK (superficial ALK n = 9; laser-assisted ALK n = 7; and epikeratophakia n = 5) underwent large-diameter (9-mm) DALK. The surgery involved deep trephination based on the anterior segment optical coherence tomography pachymetry measurement at 9-mm diameter, pneumatic dissection from the base of the trephination and limited stromal clearance of the optical zone (6 mm). Main outcome measures were success rates of pneumatic dissection, best spectacle-corrected visual acuity, and complication rates. Results Pneumatic dissection with type 1 bubble formation succeeded in 19 (90%) eyes. In the 2 remaining cases, the 6-mm optical zone was cleared by manual dissection. Perforation occurred in one of the latter cases; no procedure was converted to penetrating keratoplasty. One month after complete suture removal, the preoperative mean best spectacle-corrected visual acuity (0.75 ± 0.23 logMAR) improved to 0.09 ± 0.10 logMAR (P Conclusions Even in eyes with previous ALK, pneumatic dissection can be achieved through a modified DALK technique with a low risk of complications and excellent visual and refractive outcomes.