A Comparison Of Topographic and Refractive Effects from Arcuate Incisions in Keratoplasty: Deep Anterior Lamellar Vs. Penetrating

Purpose: To compare the topographic and refractive effects from the arcuate relaxing incisions in treating post-keratoplasty astigmatism after deep anterior lamellar keratoplasty (DALK), penetrating keratoplasty (PKP). Setting: A one center study: Devers Eye Institute, Portland, Oregon, USA.

Design: Retrospective review of consecutive cases. Methods: The study is divided into two groups: DALK and PKP group. Each group contains 20 eyes with residual astigmatism more than 4 Diopters (D) 3 months after full suture removal. Subjects underwent arcuate relaxing incision at 90% depth of the thinnest point at the steepest hemi-meridian. The corneal and refractive astigmatism, spherical equivalent, refraction and BCSVA were compared preoperative and 3 months postoperative.

Results: Topographic astigmatism improved by 3.5 ± 3.18 D in PKP, and 3.89 ± 4.92 D in DALK group (p-value = 0.051), Refractive astigmatism improved in DALK group by 2.9 ± 3.08 D and in PKP by 1.6 ± 2.64 D, (p-value = 0.163). The mean spherical equivalent changed by -0.72 ± 1.5 D in PKP, and -1.99 ± 2.45 D in DALK group, (p-value = 0.206). The Difference Vector in DALK group was 8.44 ± 13.54 D, and in PKP, it was 4.7 ± 2.12 D.

Conclusion: The arcuate relaxing incision is an effective procedure for reducing post-keratoplasty astigmatism. There was a variation of response that may be due to the biomechanics of the healed graft; future studies should be using a Femtosecond laser in an extensive series of eyes with equivalent levels of astigmatism. This may also allow for a lower, tighter range of effect in both groups.