Clinical outcomes of Bowman-Stromal inlay and corneal collagen crosslinking in contralateral eyes in patients with progressive keratoconus.

PURPOSE: This study aims to report the outcomes of Bowman-Stromal Inlay (BSI) versus corneal collagen crosslinking (CXL) in patients with progressive keratoconus.

METHODS: A retrospective, nonrandomized, interventional, comparative study included 16 patients (n = 32 eyes) with bilateral keratoconus. We analyzed the medical records of patients who had undergone CXL in one eye and BSI in the other, with a minimum follow-up period of 12 months. The medical records were reviewed for outcomes in the form of refractive and tomographic parameters.

RESULTS: A total of 16 patients (32 eyes; 16 CXL, 16 BSI) were included in the study. The mean follow-up period was 30.64 ± 6.14 months in the CXL group and 29.5 ± 5.9 months in the BSI group (range: 6 - 61 months). The visual improvement after surgery was better in the BSI group compared to the CXL group, although the changes were not statistically significant (P (UCVA) = 0.25, P (BCVA) = 0.56). No change was observed in the post-operative Kmax and Kmean values throughout the follow-up period in both groups. The postoperative corneal thickness increased significantly in the BSI group (P < 0.001), while it remained unchanged in the CXL group (P = 0.14). After these initial postoperative changes, the pachymetry remained stable throughout the follow-up period. The BSI group showed a significant improvement in asphericity (P = 0.02) postoperatively, whereas asphericity remained unchanged after CXL (P = 0.89). Topographic astigmatism did not show significant changes in either group after surgery compared to the preoperative values. Neither group had any eyes showing the progression of tomographic parameters.

CONCLUSION: Both CXL and BSI demonstrated efficacy in preventing the progression of ectasia in keratoconus. BSI showed additional benefits of improved asphericity and increased pachymetry compared to CXL.