CUSTOM ADJUSTMENTS OF CAIRS (KERANATURAL) ACCORDING TO INDIVIDUAL KERATOCONUS RESPONSE FOLLOWING INITIAL OPERATION: INSIGHTS FROM İSTANBUL NOMOGRAM

To evaluate the efficacy and feasibility of allograft corneal ring revisions to improve outcomes in the treatment of keratoconus.

Diyadin State Hospital, Agri; Turkey; Istanbul Medipol University, Faculty of Medicine, Istanbul, Turkey; Swiss Vision Clinic, Istanbul, Turkey

This retrospective case series analyses 12 keratoconus patients requiring revision from our allograft ring implantation series of 198 eyes. Patients who had previously undergone allograft corneal ring segments implantation using the Istanbul nomogram underwent various revision procedures due to unsatisfactory visual and topographic results. Uncorrected and corrected visual acuity (UDVA, CDVA), refraction, topographically derived maximum and mean keratometry (Kmax, Kmean) were analysed to evaluate the results. The time from initial surgery to revision and the revision procedures performed were also reviewed.

The surgical procedures performed included shortening in three cases, strengthening in six cases, and thinning, rotation and extension in one case each. Mean interval between the initial operation and subsequent revision was 9.86 ± 12.51 months (9 days – 40 months). No decline in visual acuity was observed in any patient following the revision procedure. In nine patients, uncorrected visual acuity increased, while in three patients, no change was observed. Corrected visual acuity increased at least one line in all patients.

Topography-guided revision of allograft rings can result in improved topographic, refractive and visual outcomes in patients with unsatisfactory initial results. Allograft rings offer the surgeon a unique opportunity to shape the cornea with their adjustable structure. A comprehensive examination of corneal topography can assist the surgeon in the creation of an effective treatment plan, ultimately leading to enhanced outcomes for both the surgeon and the patient.