Effect of a standard paired arcuate incision and augmentation sutures on postkeratoplasty astigmatism

Abstract

Purpose To analyze the efficacy of a standardized paired arcuate incision and augmentation suture technique in the treatment of various levels of post-penetrating keratoplasty (PKP) astigmatism. Setting Lions Eye Institute, Royal Perth Hospital, Perth, Australia, and University of Dundee Department of Ophthalmology, Dundee, United Kingdom. Methods A standardized paired arcuate incision and paired augmentation suture technique was used to treat 34 eyes with post-PKP astigmatism ranging from −3.50 to −20.00 diopters (D) at the spectacle plane. The technique consisted of paired arcuate incisions of 3 clock hours, 480 μm deep in the graft–host junction, and 2 pairs of augmentation 10-0 nylon sutures. Results The mean preoperative cylinder was −9.14 D ± 4.38 (SD) and the mean postoperative cylinder, −3.59 ± 1.92 D at the corneal plane after a mean follow-up of 50 ± 43 weeks. This represents an empirical reduction in mean cylinder of 5.55 D (60.7%). The Alpins correction index (surgically induced astigmatism [SIA] divided by target induced astigmatism) was calculated for each case, and the mean was 1.01 ± 0.34, with a median of 0.91. Approximately 53.1% of cases achieved a correction index between 0.80 and 1.20, and the correction index correlated poorly with the initial magnitude of cylinder. A direct numerical relationship between SIA and the initial magnitude of cylinder was observed, although a standard surgical procedure was used in all cases. Conclusion A simple standardized technique using paired arcuate incisions in the graft–host junction with paired augmentation sutures reduces the amount of cylinder in proportion to the magnitude of the preoperative cylinder and effectively reduces post-PKP astigmatism.