Three-year clinical outcome after penetrating keratoplasty for keratoconuswith the guided trephine system

PURPOSE: To determine the long-term clinical outcome after keratoplasty wit h the guided trephine system in keratoconus eyes. METHODS: In a prospective study, all consecutive cases of penetrating kerat oplasty had trephination performed with the guided trephine system, with wh ich both donor and recipient cornea are trephined from the epithelial side with a same-sized blade. For wound closure, a double running antitorque sut ure technique with 10-0 nylon was used. Uncorrected and best-corrected Snel len visual acuity, subjective refraction, and astigmatism by keratometry we re evaluated after final suture removal, 2 and 3 years postoperatively. RESULTS: In the 31 patients (31 eyes) enrolled, mean best-corrected visual acuity improved from 0.72 +/- 0.16 (20/30) after final suture removal to 0. 88 +/- 0.15 (20/25) 3 years postoperatively (P < .001). The mean spherical equivalent increased from -0.86 +/- 2.10 diopters after final suture remova l to -2.35 +/- 2.65 diopters 3 years postoperatively (P < .001). Mean kerat ometric astigmatism decreased from 4.68 +/- 1.76 diopters after final sutur e removal to 3.57 +/- 1.37 diopters 3 years postoperatively (P = .001), Fur thermore, an increase in mean keratometric levels with time (P = .01) was o bserved and associated with myopic shift (r(S) = -.46, P = .008). CONCLUSION: With the guided trephine system, we attained favorable visual r esults, with prolonged improvement of visual acuity during the entire follo w-up period; Our data show low and decreasing degrees of corneal astigmatis m over time. During the follow-up period, a myopic shift was found after fi nal suture removal. Nevertheless, this technique of performing same-sized g rafts reduces postoperative residual myopia. (Am J Ophthalmol 1999;127:666- 673. (C) 1999 by Elsevier Science Inc. All rights reserved.).