Dear Editor,
Intrastromal corneal ring segments (ICRSs; INTACSs) are approved for treating mild myopia and keratoconus. Colin et al.[1] first demonstrated their effectiveness in 2000. They flatten the central cornea by reducing arc length. Complications [Table 1], though rare, include inflammation, keratitis, vision fluctuations, perforation, and extrusion.[2,3] We present an interesting case of spontaneous INTACS extrusion one-year post-implantation, managed with Corneal Allogenic Intrastromal Ring Segments (CAIRS).
Table 1.
| Feature | INTACS (Intracorneal Rings) | CAIRS (Corneal Allogenic Intrastromal Ring Segments) |
|---|---|---|
| Effectiveness | Improves visual acuity by an arc-shortening effect. | Has an arc-shortening effect and also a volume-building procedure. |
| Planning | Has standard nomograms with a good visual outcome. | No nomograms, variable results. |
| Invasiveness | Minimally invasive, rings are inserted into the cornea. | Minimally invasive but requires donor tissue. |
| Suitability | Best for mild to moderate keratoconus. | Suitable even for more advanced keratoconus. |
| Recovery time | Fast recovery, most patients return to normal activities within days. | Recovery is also fast. |
| Risk of complications | More risk for ring migration/extrusion and intrusion. | Risk of infection but no risk of migration. |
| Availability of treatment | Available in most ophthalmic centers. | Limited availability due to the need for donor tissue. |
| Cost | Higher cost compared to CAIRS. | Lower cost. |
| Long-term outcome | Rigidity of segments gives good visual outcomes. | Offers sustained corneal stability without risk of major complications. |
A 26-year-old female with Stage 1 keratoconus (modified Krumeich classification) in both eyes presented for evaluation. Her best-corrected visual acuity (BCVA) was 6/9p in the right eye with − 1.00DS and − 4.50DC × 50. She was advised to undergo INTACS with corneal collagen crosslinking (CXL) in the right eye. Surgery was uneventful, and at two months, her BCVA was 6/6 with − 1.00DC × 20 in the right eye.
One year later, she presented with irritation in the right eye and a history of chronic eye rubbing. Slit lamp examination revealed INTACSs exposure [Fig. 1] nasally, and BCVA was 6/9. INTACS was explanted and replaced with CAIRS. The CAIRS segment was trimmed and inserted into the existing channel, sealed with fibrin glue, and a bandage contact lens was placed. Postoperatively [Fig. 2], vision remained stable at 6/9, and at 3 months follow-up, vision was 6/9 with − 1.50 cylinder.
Figure 1.
(a): Slit lamp photograph of the right eye showing INTACS extrusion nasally, (b): ASOCT image of right eye showing corneal melting with INTACS extrusion
Figure 2.
(a): Post-operative slit lamp photograph of the Right eye after CAIRS implantation, (b): ASOCT image showing the CAIRS segment well placed in the cornea
Conclusion
INTACSs are a viable treatment option for patients with keratoconus, with the added advantage of preserving corneal asphericity. The risk of complications is generally low, but extrusion, while rare, can occur, particularly in patients with a history of chronic eye rubbing. In this case, the extrusion was successfully managed with CAIRS, leading to good visual outcomes. When using INTACSs to treat keratoconus, it is crucial to educate patients on the importance of avoiding eye rubbing and to provide appropriate lubrication to minimize the risk of complications.[4,5]
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Conflicts of interest:
There are no conflicts of interest.
Funding Statement
Nil.
References
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