Combining Crosslinking With Corneal Intrastromal Ring Segments (Cairs) In Advanced Keratoconus , Post Lasik Ectasia And Contact Lens Intolerance Patients.

To evaluate the safety, visual outcomes and corneal topographic changes following implantation of Corneal Allogenic Intrastromal Ring Segments (CAIRS) combined with crosslinking in eyes with advanced keratoconus, post-LASIK ectasia and severe contact lens intolerance.

Tertiary eye care with advanced Cornea and Refractive services

This prospective interventional case series included eyes with Advanced keratoconus unsuitable for conventional ICRS, Post-LASIK ectasia with progressive irregular astigmatism and severe contact lens intolerance with poor spectacle-corrected vision.

All patients underwent femtosecond laser–assisted stromal channel creation followed by implantation of customized allogenic corneal ring segments. It was combined with accelerated CXL in the same sitting.

Pre- and postoperative evaluation  included:

• Uncorrected distance visual acuity (UDVA)

• Corrected distance visual acuity (CDVA)

• Manifest refraction

• Corneal topography and

• Anterior segment OCT

The case series included eyes with advanced ectatic disorders (mean preoperative Kmax >70D in  advanced keratoconus, >57 D in post-LASIK ectasia and > 60D in the case of contact lens intolerance).

Postoperatively:

• Significant improvement in UDVA and CDVA was observed in all eyes.

• Mean Kmax reduction ranged between 8- 15D

• Spherical equivalent significantly reduced

• Corneal symmetry improved on topography with reduction in coma and higher-order aberrations.

• The patient with contact lens intolerance achieved functional unaided vision and improved quality of life.

• No intraoperative or postoperative complications such as extrusion, infection, or stromal melt were noted during follow-up.

CAIRS is a safe and effective therapeutic option in complex corneal ectasia,including advanced keratoconus and post-LASIK ectasia. It provides good visual rehabilitation,significant corneal flattening and improved corneal regularity while preserving biomechanical integrity. Additionally,CAIRS offers a promising alternative in patients with contact lens intolerance, potentially delaying or avoiding keratoplasty.

CAIRS has significant advantages over the INATCS as they are allogenic and thus bio compatible,with no chances of extrusion,melts or vascularisation.It can be safely performed even in thinner or steeper corneas,can be inserted within a smaller optic zone with less photic phenomenon and can be easily customised as as per the topgraphy.