Impact of Residual Stromal Thickness on the Outcomes of Manual Deep Anterior Lamellar Keratoplasty.

PURPOSE: To analyze how postoperative outcomes of manual deep anterior lamellar keratoplasty (mDALK) in eyes affected by keratoconus are influenced by the residual stromal thickness (RST) of the recipient.

METHODS

Retrospective interventional case series. Patients underwent DALK between 2011 and 2025 at "Magna Graecia" University of Catanzaro, Italy. Big-bubble DALK was the favorite stromal dissection technique, whereas mDALK was reserved as backup strategy. Best spectacle-corrected visual acuity (BSCVA) and tomographic parameters were evaluated preoperatively (T0) and postoperatively after complete suture removal (1 year, T2). RST was assessed 1 month postoperatively (T1) using the CASIA SS-1000 anterior-segment optical coherence tomography (Tomey, Nagoya, Japan). Measurements were performed at the center of the cornea and at 12 paracentral points along 6 different meridians equally spaced at 30 degrees.

RESULTS

In total, 288 eyes underwent DALK. Of these, 234 (81.3%) underwent successful pneumatic or viscoelastic dissection, whereas 54 (18.7%) required mDALK. In this subgroup, a significant correlation was found between postoperative BSCVA and central RST [56.17 ± 15.43 μm (95% confidence interval: 52.06-60.29); ρ = 0.397, P = 0.003], but not with paracentral RST [66.75 ± 22.54 μm (95% confidence interval: 60.74-72.76); ρ = 0.24, P = 0.07].

CONCLUSIONS

Central RST presented a low-moderate yet significant correlation with postoperative BSCVA at 1 year. Corneal surgeons should aim to minimize RST compatibly with a safe stromal dissection.