RESUMO
PURPOSE: To evaluate the efficacy and safety of a single intrastromal corneal ring segment (ICRS) (450 µm Intacs SK) in moderate to severe keratoconic eyes with an inferiorly located cone and a noninvolved center. SETTING: Ophthalmology Department, American University of Beirut Medical Center, Beirut, Lebanon. DESIGN: Retrospective case series. METHODS: The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, central and inferior maximum topographic keratometry (K) values, manifest cylinder, and spherical equivalent (SE) were recorded preoperatively and 1 week and 1, 3, and 6 months postoperatively. RESULTS: Thirty eyes were studied. The mean age was 29.6 years ± 8.0 (SD). The mean preoperative UDVA and CDVA were 20/86 and 20/42, respectively. The mean center K was 49.14 ± 4.39 diopters (D); the mean maximum K, 56.78 ± 6.02 D; and the mean center K - maximum K, -7.45 ± 5.61 D. The mean SE and cylinder were -2.24 ± 2.32 D and -4.33 ± 1.43 D, respectively, with sphere ranging from +2.00 to -18.00 D. At 6 months, the UDVA improved to 20/32. The mean SE was -1.02 ± 2.04 D (P = .0330); the mean cylinder, -1.67 ± 1.00 D (P < .00); and the mean center K - maximum K, -4.92 ± 4.36 D (P < .05). The CDVA improved more than 2 lines; no eye lost any lines. Topographic indices improved in all eyes. CONCLUSIONS: Single ICRS implantation in eyes with moderate to severe keratoconus and inferiorly located cones was safe and effective. The development of a nomogram relying more on topographic data is suggested. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
