Effect of Keratoconus Severity on Clinical outcomes after Deep Anterior Lamellar Keratoplasty

Purpose: To evaluate the effect of keratoconus severity on visual and refractive outcomes and complications after deep anterior lamellar keratoplasty (DALK). Methods: This consecutive interventional case series enrolled 227 keratoconus-affected eyes that underwent DALK. The Amsler-Krumeich keratoconus classification was used to categorize the patients: stage II, 47 eyes; stage III, 60 eyes; and stage IV, 120 eyes. The outcome measures including postoperative best-spectacle corrected visual acuity (BSCVA), spherical equivalent refraction, mean keratometry, keratometric astigmatism, and complications were analyzed and compared according to keratoconus stage.Results: The mean patient age was 27.6±8.0 years and the mean follow-up period was 38.0±19.8 months. No significant differences were observed in postoperative BSCVA (P=0.55), spherical equivalent refraction (P=0.27), mean keratometry (P=0.09), and keratometric astigmatism (P=0.14) among the groups. Changes in BSCVA were significantly greater in stage III and stage IV than in stage II (P=0.04 and <0.001, respectively). The decrease in spherical equivalent was significantly greater in stages III and IV than in stage II (P=0.04 and 0.001, respectively). Mean keratometry decreased to a greater degree in stage IV than in stages II and III (P<0.001 for both comparisons). The study groups were comparable with respect to intraoperative Descemet membrane perforation, suture-related complications, and graft rejection. Conclusion: DALK is a safe and effective procedure for the treatment of keratoconus of all stages. This technique of corneal transplantation is more effective in eyes with severe keratoconus than those with moderatekeratoconus.