A meta-analysis published in the American Journal of Ophthalmology has highlighted the growing clinical potential of Corneal Allogeneic Intrastromal Ring Segments (CAIRS) as a safe and effective treatment for keratoconus. The systematic review, which included data from 14 clinical studies and 442 eyes, found that CAIRS implantation leads to significant improvements in visual acuity, corneal shape, and refractive error – with fewer complications than traditional synthetic ring implants.
The meta-analysis showed a mean improvement of 0.37 logMAR in corrected distance visual acuity (CDVA) and 0.43 logMAR in uncorrected distance visual acuity (UDVA). Additionally, spherical equivalent improved by 4.59 diopters, and maximum keratometry (Kmax) was reduced by 4.49 diopters. These outcomes suggest that CAIRS provides similar or better efficacy compared to synthetic Intracorneal Ring Segments (ICRS), but with a lower risk of complications.
From the 353 patients observed, only one severe adverse event was reported, with mild complications such as implant opacification or deposits being seen in approximately 4 percent of cases. Notably, patients experienced fewer visual disturbances (like glare and halos) compared to those with synthetic implants, likely due to the superior biocompatibility of allogeneic tissue.
The University of Heidelberg-based researchers emphasize that the customizable nature of CAIRS – via femtosecond laser shaping or manual trephines – makes it a flexible tool for treating a wide range of keratoconus phenotypes. Though current evidence is based largely on non-randomized studies with short follow-up, the findings support CAIRS as a promising option for improving vision and quality of life in keratoconus patients, especially those who are not yet candidates for keratoplasty.
