title: Effect of recipient-donor trephine size disparity on refractive error in keratoconus.
abstract: A retrospective study was performed to evaluate the effect of recipient-donor trephine disparity on refractive error and corneal curvature post-suture removal in keratoconus. A double running suture technique was used and donor corneas were trephined from the endothelial side. When keratoconus patients with 0.25-mm larger donor than recipient trephines were compared with keratoconus patients with the same size recipient and donor trephines, a statistically significant increase in the mean keratometer value (45.4 and 43.8 diopters [D], respectively; P = 0.03) and increase in myopic spherical equivalent (-3.5 and -1.8 D, respectively; P = 0.03) was found. When keratoconus patients were compared with phakic Fuchs' dystrophy patients (both groups had 0.25-mm oversize donor trephines), the keratoconus group had a statistically significantly higher myopic spherical equivalent (-3.5 and -1.4 D, respectively; P = 0.03) despite only a 0.7-D difference in mean keratometer value which was not statistically significant (45.4 and 44.7 D, respectively). This study supports the hypothesis that the degree of post-penetrating keratoplasty myopia in patients with keratoconus can be decreased by reducing recipient-donor trephine disparity.
authors.affiliation: Department of Ophthalmology, Mayo Clinic, Rochester, MN 55905.
authors.forename: S E
authors.initials: SE
authors.lastname: Wilson
authors.forename: W M
authors.initials: WM
authors.lastname: Bourne
mesh_terms: D003317:Corneal Dystrophies, Hereditary / Q000601:surgery*; D016039:Corneal Transplantation; D005642:Fuchs' Endothelial Dystrophy / Q000601:surgery*; D006801:Humans; D007640:Keratoconus / Q000601:surgery*; D009216:Myopia / Q000209:etiology*; D011183:Postoperative Complications / Q000209:etiology*; D012029:Refraction, Ocular; D012189:Retrospective Studies; D012307:Risk Factors; D014792:Visual Acuity