Intracorneal ring segments for keratoconus correction:: Long-term follow-up

PURPOSE: To evaluate long-term results and stability of intracorneal ring segment (Intacs) implantation for keratoconus correction. SETTING: Vissum, Instituto Oftalmologico de Alicante and University of Miguel Hernandez, Alicante, Spain. METHODS: This retrospective study comprised 13 eyes operated on between April 2000 and December 2001 that had Intacs implantation for keratoconus correction. The outcomes were evaluated at 6, 12, 24, and 36 months in all eyes and at 48 months (6 eyes). RESULTS: Mean best spectacle-corrected visual acuity (BSCVA) increased from 0.46 (20/50) preoperatively to 0.66 (20/30) postoperatively (P <= .001). Mean decrease of inferior-superior (I-S) asymmetry was 2.81 diopters (D) (P <= .02), and the average K-value was 3.13 D (P <=.001). Mean difference between 6 and 36 months (stability) showed no significant difference regarding BSCVA (P <= .5) and I-S asymmetry (P <= .6). Although a significant increase was noticed in the average K by 1.67 D (P <= .002), at 36 months it did not reach the initial preoperative values. CONCLUSION: Intacs increased the BSCVA and decreased I-S asymmetry with stability up to 36 months. in spite of the decrease of the K-values at 6 months, a further significant increase was detected 36 months after surgery.