Long-term progression of astigmatism after penetrating keratoplasty for keratoconus: evidence of late recurrence

Abstract

The authors retrospectively reviewed progression of astigmatism in 80 eyes that underwent penetrating keratoplasty for keratoconus for which a mean follow-up of 20 years (range, 15–25 years) was available. Graft size, suture technique, and time of suture removal had no significant influence on the astigmatism at the last examination. There was stabilization of keratometric astigmatism in the first 7 years after suture removal (4.05 ± 2.29 diopters (D) at year 1, 4.39 ± 2.48 D at year 7). There was a progressive increase in keratometric astigmatism beginning in the 10th year after suture removal and continuing until the last follow-up visit (5.48 ± 3.11 D at year 10, 6.43 ± 4.11 D at year 15, 7.28 ± 4.21 D at year 20, and 7.25 ± 4.27 D at year 25). There was a significant correlation between the preoperative and final axis of astigmatism (P = .0008). The major slit-lamp finding was a peripheral crescent of thinning at the graft–host junction with absence of the Bowman layer on histopathology. The authors conclude the late onset of progressive astigmatism is related to progression of keratoconus in the host cornea.—Michael D. Wagoner