COMPARATIVE OUTCOMES OF CORNEAL ALLOGENIC RING SEGMENTS (CAIRS) BASED ON TOPOGRAPHIC CONE PATTERNS IN KERATOCONUS
Published 2026 - 30th ESCRS Winter Meeting
Reference: FP05.12 | Type: Free Paper | DOI: 10.82333/b9sf-qx22
Authors: Dilan Çolak 1 , Burcu Yakut* 2 , Metin Suleymanzade 3 , Sepide Lotfi 3 , Uğur Tunç 4 , Fatma Feyza Nur Keskin Perk 5 , Aylin Kılıç 3
1Ophthalmology,Beyoglu Eye Training and Research Hospital,Istanbul,Türkiye, 2Ophthalmology,Haseki Training and Research Hospital,Istanbul,Türkiye, 3Ophthalmology,Biruni University,Istanbul,Türkiye, 4Ophthalmology,Medipol University,Istanbul,Türkiye, 5Ophthalmology,Başakşehir Çam and Sakura City Hospital,Istanbul,Türkiye
Purpose
To evaluate the visual and refractive outcomes of Corneal Allogenic Intrastromal Ring Segment (CAIRS) implantation in keratoconus patients with different topographic morphologies.
Setting
Swiss Vision Clinic, İstanbul, Türkiye
Methods
This retrospective study included 215 eyes of 185 patients who underwent CAIRS implantation for keratoconus between February 2020 and January 2025. Patients were divided into three groups based on corneal topography: hemifield, asymmetric bowtie, and diffuse/central involvement. The hemifield group included eyes with inferior steepening, superior steepening, or junctional patterns. The asymmetric bowtie group comprised eyes with asymmetric bowtie with inferior steepening (AB/IS), asymmetric bowtie with superior steepening (AB/SS), and asymmetric bowtie with skewed radial axis (AB/SRAX). The diffuse/central group included eyes with symmetric bowtie, symmetric bowtie with SRAX, oval, and irregular patterns. Preoperative and postoperative uncorrected (UCVA) and corrected distance visual acuity (CDVA), refraction, keratometric parameters, and pachymetry were analyzed. All surgeries were performed by a single experienced surgeon using a femtosecond laser–assisted technique. Statistical analyses were conducted using nonparametric tests, with p < 0.05 considered significant.
Results
All groups demonstrated significant postoperative improvement in UCVA, CDVA, spherical equivalent, and keratometric values (p < 0.001). The hemifield group achieved the best postoperative UCVA and CDVA, while the diffuse/central group showed the lowest final visual acuity but the greatest visual gain (ΔCDVA: 0.67 ± 0.53 logMAR, p < 0.05). No significant intergroup differences were observed in keratometric or pachymetric changes. Anatomical and functional improvements were observed in all subgroups following CAIRS implantation.
Conclusion
CAIRS implantation using KeraNatural segments provided significant visual and refractive improvements across all keratoconus morphology types. Although patients with diffuse or central involvement achieved lower final visual acuity, they experienced the most pronounced functional gains, suggesting CAIRS may be beneficial even in advanced or diffuse keratoconus patterns.