Indications for intrastromal corneal ring segments in ectasia after laser in situ keratomileusis

PURPOSE: To evaluate clinical results of intrastromal corneal ring segments (ICRS) in a large series of post-laser in situ keratomileusis (LASIK) ectasia and determine which clinical parameters were related to the success of this technique. SETTINGS: Vissum Corporation and Clinica Baviera Group, Alicante, Spain. DESIGN: Case series. METHODS: Intrastromal corneal ring segments were implanted to correct the spherocylindrical error and improve visual acuity. Based on a previously described grading system, the best indications for ICRS implantation to treat post-LASIK ectasia were evaluated. The variables related to favorable outcomes over a 12-month follow-up were determined. RESULTS: Patients who lost 2 or more lines due to post-LASIK ectasia had a mean gain of +2.89 lines of corrected distance visual acuity (CDVA) after ICRS implantation (P<.001) and a mean CDVA of 0.81 (95% confidence interval, 0.74-0.88). In contrast, patients who did not lose vision after ectasia had a mean loss of -2.00 lines of CDVA after the ICRS implantation (P<.001). The odds ratio of a gain of at least 1 line of CDVA was 18 times greater for those who had lost 2 or more lines of CDVA after ectasia. CONCLUSIONS: The best indications for ICRS were a loss of 2 or more lines of CDVA after ectasia and post-LASIK ectasia grade 4. Patients who do not have vision loss after ectasia and those classified as grade 1 should not be considered candidates for ICRS implantation.