Long-term Follow-up of Intacs in Keratoconus

Purpose: To evaluate long-term follow-up of Intacs microthin prescription inserts (Addition Technology, Inc, Fremont, California, USA) for the management of keratoconus. Design: A long-term (five years) retrospective, follow-up study. Methods: Seventeen eyes of 15 patients with keratoconus ages 24 to 52 years (mean age ± standard deviation [SD], 34.0 ± 10.5 years) who had completed five years of follow-up (mean follow-up ± SD, 67.2 ± 7.5 months; range, 58 to 78 months) were included. Two Intacs segments of 0.45-mm thickness were inserted in the cornea of each eye, aiming at embracing the keratoconus area to try to achieve maximal flattening. Results: No late postoperative complications occurred in this series of patients. At five years, the spherical equivalent error was statistically significantly reduced (pre-Intacs, mean ± SD -5.54 ± 5.02 diopters [D]; range, -12.50 to 3.63 D; -3.02 ± 2.65 D; range, -8.25 to 1.88 D) (P = .01). Pre-Intacs uncorrected visual acuity (UCVA) was 20/50 or worse in all eyes (range, counting fingers to 20/50), whereas, at the last follow-up examination, 10 (59%) of 17 eyes had UCVA of 20/50 or better (range, counting fingers to 20/32). Six eyes (35%) maintained the pre-Intacs best spectacle-corrected visual acuity (BSCVA) and one eye lost 3 lines of BSCVA, whereas the rest of the 10 eyes (59%) experienced a gain of one up to 8 lines. Conclusions: After five years, intracorneal ring segments implantation improved UCVA, BSCVA, and refraction in the majority of the keratoconus patients. There was no evidence of progressive sight-threatening complications in this study.