Preoperative Keratoconus Stage Does Not Predict DALK Surgery Outcomes

Preoperative keratoconus stage cannot provide predictive data for patients undergoing deep anterior lamellar keratoplasty (DALK) surgery, according to a report published in Cornea. Researchers say the Amsler-Krumeich keratoconus classification system does not affect postoperative outcomes or complications — thus, the timing of the surgery should be planned with the awareness that disease progression does not negatively affect outcomes.

Researchers evaluated surgery response in 137 eyes of 137 adults patients with keratoconus stage 3 or 4 (54 with stage 3, and 83 with stage 4) keratoconus, who underwent DALK from January 2013 to December 2021.

Mean patient age was 31.28±9.66 years, and follow-up time 42.20±24.36 months. Investigators retrospectively analyzed pre- and postoperative differences, excluding data for eyes with intraoperative Descemet’s membrane (DM) macroperforation.

Patients of various preoperative keratoconus stages did not significantly differ when evaluated for postoperative best-corrected visual acuity (BCVA), corneal thickness, K_mean value, spherical equivalent, or topographic astigmatism (all P >.05). No correlations arose when considering baseline BCVA, corneal thickness, K_mean value, and refractive error compared with postoperative BCVA. Overall, no statistically meaningful correlation appeared for pre- and post-surgery factors (all P >.05).

Eyes with preoperative keratoconus stage 4 experienced DM perforation and early loosening of sutures more often than those with preoperative keratoconus stage 3, but these and other complications did not show statistical significance between stages (all P >.05).

Among 43 eyes with corneal scarring after a prior hydrops, 4 had an intraoperative DM microperforation vs 3 of 94 eyes without scarring (P =.132).

“According to our outcomes, we suggest that suture-related factors, such as suture depth and tension, and also graft size can influence postoperative corneal keratometry values more than preoperative factors,” the investigators suggest.

Limitations of the investigation include possible slight differences among surgeons, and lack of data for pre- vs post-op endothelial layer characteristics. However, the new data contributes to limited information available regarding the impact of preoperative severity on DALK outcomes.