Enhanced Insertion Of Corneal Allogenic Intrastromal Ring Segments (Cairs) With Extended Dehydration And A Pointy Tip Modification

To evaluate the effectiveness of combining extended dehydration with a pointy tip modification in facilitating the insertion of corneal allogenic intrastromal ring segments (CAIRS). This study compares the modified technique with the standard dehydration method, assessing its impact on insertion ease, surgical time, and the need for rescue incisions. By optimizing segment rigidity and shape, this approach aims to improve implantation efficiency while ensuring precise anatomical placement and clinical outcomes.

A retrospective comparative study of 24 consecutive cases, including 12 cases using the standard dehydration technique and 12 cases with the pointy tip modification. All surgeries were performed by a single surgeon, (JA). CAIRS were prepared from donor corneas using Soosan Jacob trephines. After trephination, segments were dehydrated for 60 minutes in the Awwad drying mold and trimmed with Wescott scissors to create a pointy distal tip. Segments were implanted into femtosecond laser-created tight tunnels, with 500 µm thick segments placed in 700 µm width tunnels and 750 µm thick segments placed in 900 µm width tunnels. Outcomes included insertion ease, the need for a rescue incision, and insertion time.

The combination of extended dehydration and pointy tip modification significantly improved CAIRS insertion ease and speed. No cases in the modified group required a rescue incision, versus 50% in the standard dehydration group. The mean insertion time was 36 ± 6.9 seconds in the modified group, significantly shorter than 182 ± 227.8 seconds with standard dehydration (p < 0.05). Postoperative Ms39 AS-OCT confirmed proper segment positioning in both groups, with no significant differences in final placement within the corneal stroma.

Combining extended dehydration with a pointy tip modification significantly improves CAIRS insertion by reducing resistance during placement, shortening surgical time, and eliminating the need for rescue incisions. While extended dehydration enhances segment rigidity in both groups, the pointy tip facilitates smoother insertion into tight tunnels. Postoperative segment positioning was comparable between the two techniques, confirming that the modification does not alter the intended placement.