ELZA Researchers Publish JCRS Study on Cross-Linked Allogenic Corneal Ring Segments
Researchers affiliated with the ELZA Institute have published a new peer-reviewed article in the Journal of Cataract & Refractive Surgery on the biomechanical stiffening of cross-linked allogenic corneal ring segments.
The article, titled “Biomechanical Stiffening Effect in Ultra-High-Fluence Extracorporeal Cross-Linked Corneal Allogenic Intrastromal Ring Segments,” was published online ahead of final publication by Wolters Kluwer. The study examines a laboratory-based approach to improving the mechanical properties of corneal allogenic intrastromal ring segments before implantation.
Why allogenic corneal ring segments matter
Intracorneal ring segments are used in selected patients with keratoconus and other corneal ectasias to help regularize corneal shape and improve visual quality. Earlier synthetic ring segments were made from polymethylmethacrylate, or PMMA. Although these implants can reshape the cornea, synthetic material has limitations, including tissue-related complications and reduced physiological integration.
Corneal Allogenic Intrastromal Ring Segments, or CAIRS, use donor corneal tissue rather than synthetic material. This approach is designed to improve biocompatibility and tissue integration while allowing diffusion through the implanted tissue. However, donor corneal segments are naturally soft, which can make them more difficult to insert into stromal tunnels during surgery.
What the new JCRS study examined
The new study investigated whether ultra-high-fluence corneal cross-linking could increase the stiffness of allogenic corneal tissue before implantation. This approach is known as ECO-CAIRS, which stands for Extracorporeal Corneal Allogenic Intrastromal Ring Segments.
In this experimental ex vivo study, 84 porcine corneas were divided into four groups. One group served as an untreated control, while the other groups received corneal cross-linking at total fluences of 10 J/cm², 30 J/cm², or 60 J/cm². The investigators then measured the biomechanical response of the corneal tissue using stress-strain extensiometry.
The study found that cross-linking increased tissue stiffness compared with untreated control tissue. The ultra-high-fluence groups, treated with 30 J/cm² or 60 J/cm², showed greater stiffening than the conventional high-fluence 10 J/cm² group. There was no significant difference between the 30 J/cm² and 60 J/cm² groups, suggesting that 30 J/cm² may already provide substantial biomechanical optimization in this ex vivo setting.
Why this is relevant to ECO-CAIRS
The findings support the concept that ultra-high-fluence extracorporeal cross-linking can make allogenic corneal ring segments stiffer before implantation. In practical terms, this may improve surgical handling by making the segments easier to insert and position within the corneal stroma.
Because the cross-linking is performed outside the eye, the usual in vivo concerns related to endothelial safety and postoperative haze are less relevant. The study also notes that increased stiffness may help reduce segment swelling and improve the handling properties of the tissue during surgery.
A step in translational corneal biomechanics
This study adds biomechanical evidence to the development of ECO-CAIRS as an advanced approach for keratoconus rehabilitation. The work remains experimental and ex vivo, meaning that it was performed in laboratory tissue rather than in a clinical patient cohort. Further clinical studies are needed to evaluate long-term segment behavior, tissue integration, corneal shape change, and visual outcomes after implantation.
For patients, the key message is that keratoconus treatment continues to move beyond disease stabilization alone. In selected cases, modern corneal surgery may also aim to improve corneal shape and optical quality. Treatment decisions, however, remain highly individualized and depend on corneal tomography, disease stage, corneal thickness, visual needs, and overall ocular health.
The article is available through the Journal of Cataract & Refractive Surgery.
Article DOI: 10.1097/j.jcrs.0000000000001981
