Intrastromal corneal ring segments for advanced keratoconus and cases with high keratometric asymmetry

Abstract

Purpose: To report the safety and efficacy of intrastromal corneal ring segment (ICRS) implantation to manage keratoconus.

Setting: Singleton Hospital Abertawe Bro Morgannwg University NHS Trust, Swansea, United Kingdom

Design: Case series.

Methods: Intacs SK ICRS were implanted manually for moderate to severe keratoconus and contact lens intolerance or ineffectiveness. Postoperative examinations were at 2 and 4 weeks; 3, 6, 9, and 12 months; and every 6 months thereafter. Outcome measures included uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, corneal topography, and slitlamp examination.

Results: This study enrolled 31 eyes (29 patients; mean age 30 years). The mean UDVA was significantly better 12 months postoperatively (0.88 logMAR) than preoperatively (1.40 logMAR) (P=.001), as was the mean CDVA (0.29 logMAR versus 0.44 logMAR) (P=.04). The mean spherical equivalent was -6.57 diopters (D) preoperatively and -2.84 D at 12 months (P=.01). The mean keratometry (K) reading decreased from 52.07 D (range 45.9 to 63.1 D) to 46.15 D (range 39.2 to 52.9 D) for K1 (P<.0001) and from 57.9 D (range 52.5 to 69.7 D) to 51.2 D (range 46.8 to 58.3 D) for K2 (P<.0001). There were no intraoperative complications; however, 6 patients had segment extrusion.

Conclusion: Implantation of ICRS was useful in managing keratoconus, producing up to 12.00 D of corneal flattening, which improved CDVA and allowed contact lens tolerance in all cases.