Original Articles
Three-year clinical outcome after penetrating keratoplasty for keratoconus with the guided trephine system

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Abstract

PURPOSE:

To determine the long-term clinical outcome after keratoplasty with the guided trephine system in keratoconus eyes.

METHODS:

In a prospective study, all consecutive cases of penetrating keratoplasty had trephination performed with the guided trephine system, with which both donor and recipient cornea are trephined from the epithelial side with a same-sized blade. For wound closure, a double running antitorque suture technique with 10-0 nylon was used. Uncorrected and best-corrected Snellen visual acuity, subjective refraction, and astigmatism by keratometry were 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 removal to −2.35 ± 2.65 diopters 3 years postoperatively (P < .001). Mean keratometric astigmatism decreased from 4.68 ± 1.76 diopters after final suture removal to 3.57 ± 1.37 diopters 3 years postoperatively (P = .001). Furthermore, an increase in mean keratometric levels with time (P = .01) was observed and associated with myopic shift (rS = −.46, P = .008).

CONCLUSION:

With the guided trephine system, we attained favorable visual results, with prolonged improvement of visual acuity during the entire follow-up period. Our data show low and decreasing degrees of corneal astigmatism over time. During the follow-up period, a myopic shift was found after final suture removal. Nevertheless, this technique of performing same-sized grafts reduces postoperative residual myopia.

Section snippets

Methods

We prospectively evaluated the data of consecutive keratoconus eyes that had not been previously operated on and in which keratoplasty was performed by one surgeon (Dr Skorpik) at the University Hospital of Vienna between 1993 and 1995. The patients were selected for surgery if visual acuity was no longer satisfactory to them, either with contact lenses or spectacles, moreover if correction with contact lenses also became impossible. Donor material was stored in Optisol media at 4 C. All the

Results

Thirty-nine patients (39 eyes) after keratoplasty for keratoconus with the guided trephine system were followed for at least 3 years. Four patients were excluded because of inadequate follow-up. The refractive outcome of four other patients could also not be evaluated. Of these four, one had a primary graft rejection and needed an immediate retransplantation, one had a severe eye injury 13 months after surgery, and two had refractive surgery before the 3-year follow-up. Thus, 31 patients (31

Discussion

Visual rehabilitation with low and stable postoperative astigmatism is the major goal of penetrating keratoplasty. Low astigmatism and optical stability permit easy correction with spectacles or contact lenses, which is of primary concern to patients. Postoperative astigmatism, refractive changes, and residual myopia are still significant problems in the management of patients with keratoconus after penetrating keratoplasty. The causes of postoperative astigmatism are multifactorial.5, 6, 7, 8,

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