Purpose: To describe the clinical results of Pentacam-based big bubble deep anterior lamellar keratoplasty (DALK) to achieve an intended 90% depth of initial lamellar trephination.
Methods: Fifty consecutive eyes of 50 patients with keratoconus, keratoglobus, and anterior stromal scars were included. DALK was performed with the big bubble technique using a 90% intended depth for initial lamellar trephination based on preoperative pachymetry by Pentacam. Main outcome measures were success of surgery, best spectacle–corrected visual acuity, endothelial cell count, refractive astigmatism at 12-month follow-up, and rate of intra- and postoperative complications.
Results: In 84% of the patients (n = 42), Pentacam-based big bubble DALK could be performed successfully. Successful big bubble formation could be achieved in 80% of the patients (n = 34). In case of macroperforation (n = 8), surgery was converted to standard penetrating keratoplasty representing a conversion rate of 16%. Intraoperative microperforation (n = 5) could be handled by an intracameral air injection at the end of operation with successful completion of the lamellar procedure. No allograft rejection was observed. Best spectacle–corrected visual acuity improved from 20/125 ± 20/160 preoperatively to 20/40 ± 20/80 at 12-month follow-up. Endothelial cell count was 2102 ± 318 cells per square millimeter preoperatively and 1735 ± 420 cells per square millimeter at 12-month follow-up. Refractive astigmatism was 7.09 ± 3.13 diopters preoperatively and decreased to 4.13 ± 2.41 diopters.
Conclusion: Pentacam-based big bubble DALK using a 90% intended depth of initial lamellar trephination seems to be a safe and effective procedure for anterior corneal stromal disorders such as keratoconus. We suggest that Pentacam-based depth assessment allows for reliably deep initial preparation and may allow more successful bubble formation in DALK surgery.