Effectiveness and Safety of Contact Lens-Assisted Collagen Cross-Linking in Thin Corneas with Progressive Keratoconus: A Prospective Interventional Study

Abstract

Background: Conventional corneal collagen cross-linking (CXL) is limited to corneas with a minimum thickness of 400 μm, restricting its use in advanced keratoconus. Contact lens-assisted collagen cross-linking (CACXL) has emerged as a potential alternative for thin corneas.

Aim: To evaluate the effectiveness and safety of CACXL in progressive keratoconus with thin corneas.

Methods: This hospital-based interventional study included 75 eyes of 48 adult patients with progressive keratoconus and corneal thickness between 350–440 μm. CACXL was performed using riboflavin-soaked soft contact lenses followed by ultraviolet-A irradiation. Patients were evaluated preoperatively and at 1, 6, and 12 months postoperatively. Outcomes included corneal thickness, maximum keratometry (Kmax), endothelial cell count, and best-corrected visual acuity (BCVA). Statistical analysis was performed using paired t-test.

Results: Mean preoperative corneal thickness was 407.91 ± 23.15 μm, with no significant change at 12 months (408.36 ± 23.22 μm; p=0.433). Kmax remained stable (58.99 ± 5.36 D preoperatively vs. 58.82 ± 5.45 D at 12 months; p=0.111). Endothelial cell count showed no significant reduction (p>0.05). BCVA improved significantly from 0.65 ± 0.30 to 0.60 ± 0.29 (p=0.002).

Conclusion: CACXL is a safe and effective procedure for halting keratoconus progression in thin corneas, without significant endothelial damage. It offers a practical alternative to conventional CXL.