Keratoscope-guided opening of graft-host junction to treat elevated astigmatism after deep anterior lamellar keratoplasty

Aims To describe a simple surgical technique consisting of opening the vertical graft-host junction (GHJ) to manage high astigmatism following deep anterior lamellar keratoplasty (DALK) and to report postoperative visual and topographic outcomes. Methods This is a retrospective interventional case series. Patients affected by high astigmatism after DALK underwent progressive opening of the previous GHJ at the steep meridians, established with preoperative topography and intraoperative keratoscopic guidance. Evaluations were carried out with best corrected visual acuity (BCVA), refractive astigmatism (RA) and keratometric astigmatism (KA) measured with Casia (Tomey, Japan). Visits were conducted preoperatively (T0), 1 week (T1), 6 months (T2) and 1 year after surgery (T3). The Alpins Method was used to evaluate vectorial changes in KA between T0 and T3. Results Fifteen patients were included in the analysis. BCVA (median (IQR)) increased significantly from 0.70 (0.5-1.1) at T0 to 0.20 (0.1-0.3) logMAR at T3 (p=0.001). RA (mean±SD) at T3 was 2.28±1.59 dioptres (D). KA (mean±SD) varied significantly from 8.04±2.14 D at T0 versus 2.93±1.94 D at T1 versus 3.15±1.79 D at T2, versus 3.23±1.63 D at T3 (p<0.0001). Vectorial analysis showed that target induced astigmatism (mean±SD) was 8.04±2.14 D, while surgically induced astigmatism (mean±SD) was 7.89±4.27 D. Correction index (mean±SD) was 0.92±0.33. Conclusions High astigmatism after DALK can be safely and effectively managed by opening the GHJ down to the cleavage plane achieved with the previous surgery, providing low KA and RA, with an overall low tendency to overcorrection.