Nauman Hashmani, Sharif Hashmani, Javaria Saleem
CAIRS combined with accelerated CXL demonstrated significant improvements in visual acuity, refractive error, and keratometric parameters at 6 months. These findings suggest that CAIRS may represent a promising biological alternative to synthetic intracorneal ring segments, warranting further investigation through prospective controlled studies with longer follow-up.
PURPOSE: To evaluate the visual, tomographic, and biomechanical effects of corneal allogenic intrastromal ring segments (CAIRS) combined with accelerated epithelium-off corneal cross-linking (CXL) in patients with moderate to advanced keratoconus.
METHODS: This retrospective case series included 40 eyes of 40 patients with keratoconus. CAIRS segments were prepared from donor corneal tissue stored in Netisol medium and implanted via femtosecond laser-created intrastromal channels. Accelerated epithelium-off CXL (10 mW/cm2 for 9 minutes; total energy 5.4 J/cm2) was performed immediately after CAIRS implantation; an individualized Sub400 protocol was applied in eyes with post-implantation pachymetry below 400 µm. Outcomes at baseline and 6 months included best-corrected visual acuity (BCVA), spherical equivalent, keratometric indices, pachymetry, higher-order aberrations (HOAs), and Corvis ST biomechanical parameters.
RESULTS: Median BCVA improved from 0.52 to 0.22 logMAR (p=0.005), and spherical equivalent improved from -9.3 D to -4.1 D (p=0.007). K1, K2, Km, and Kmax showed statistically significant flattening (all p<0.05). HOAs and coma did not significantly change. SP-A1 decreased from 52.7 to 51.2 mmHg/mm (p=0.015), while integrated radius showed no significant difference. One eye (2.5%) developed donor segment opacification within the first postoperative week without functional visual consequence; BCVA improved in this eye. No rejection, extrusion, or other adverse events were recorded.
CONCLUSION: CAIRS combined with accelerated CXL demonstrated significant improvements in visual acuity, refractive error, and keratometric parameters at 6 months. These findings suggest that CAIRS may represent a promising biological alternative to synthetic intracorneal ring segments, warranting further investigation through prospective controlled studies with longer follow-up.