[Intracorneal Ring Segments to Treat Keratectasia - Interim Results and Potential Complications]

Implantation of intracorneal ring segments (ICRS) using a femtosecond laser is a minimally invasive procedure which represents a reliable option to widen the spectrum of the stage-related therapy of keratoconus in patients with contact lens intolerance, or with post-LASIK-keratectasia or pellucide marginale degeneration (PMD).

From August 2011 to September 2015, 84 eyes of 69 patients were implanted with ICRS. 74 eyes were implanted with INTACS-SK (Intacs, Addition Technology, Inc.), and 10 eyes were implanted with KeraRing SI6 (Mediaphacos Ltda.). The indication is taken in the presence of a clear central cornea and the patients had to fulfill the corneal diagnostic tests required for implantation. Tunnel creation should nowadays only be carried out by femtosecond laser, in order to avoid intra- and postoperative complications.

Three months after surgery, the INTACS-SK group showed an increase in uncorrected distance visual acuity (logMAR) from 0.99 ± 0.35 to 0.29 ± 0.17. The KeraRing SI6 group showed an increase in uncorrected distance visual acuity (logMAR) from 0.93 ± 0.4 to 0.41 ± 0.34. The keratometric values were reduced in both groups.

Uncorrected and corrected distance visual acuity can be improved by implantation of the ICRS. Progression of ectasia seems to be retarded. Consistent follow-up visits at close intervals are necessary to identify complications at an early stage. However, larger case series and a longer postoperative observation period are required. Complications after ICRS implantation are rare, due to strict patient selection and modern surgical techniques.