Descemetic DALK and Predescemetic DALK: Outcomes in 236 Cases of Keratoconus

Purpose: To report the outcomes of our experience with deep anterior lamellar keratoplasty (DALK) in patients with keratoconus.

Methods: A retrospective evaluation of 236 eyes of 198 patients that have undergone DALK between 2000 and 2006 using the Tsubota, Sugita, Melles, or Anwar technique. We analyzed the frequency of true Descemet membrane exposure, which we termed dDALK, and the number of eyes in which a predescemetic plane was achieved, which we termed pdDALK. Pre- and postoperative visual acuity, endothelial cell count, and central corneal thickness were evaluated on 120 eyes followed in our department.

Results: A total of 139 of 236 (59%) eyes were classified as dDALK, with the Anwar technique showing the highest incidence of exposure of Descemet's membrane (127 of 164, 77%). Descemet ruptures occurred in 25 of 236 cases (10.5%). Three ruptures were converted to penetrating keratoplasty (PK). There was no difference in visual acuity between the pdDALK and dDALK groups at an average follow-up of 30.4 months, although the eyes in the dDALK group seemed to have faster visual recovery. Best spectacle corrected visual acuity postoperatively was at least 20/30 in 80-85% of eyes at the patient's last visit. Endothelial cell loss was 11-13%, with most of the loss occurring in the first 6 months.

Conclusions: Performing DALK, we had the greatest likelihood of reaching Descemet's membrane with the Anwar Big Bubble technique. The visual outcomes are comparable to standard PK, avoiding the risk of endothelial rejection. Endothelial cell loss was low and the cell count was stable after 6 months.