[Penetrating keratoplasty with intrastromal corneal ring. A prospective randomized study].

Background: The purpose of the study was to evaluate the efficacy and safety of Krumeichs' intrastromal corneal ring following penetrating keratoplasty. Postoperative astigmatism and occurrence of complications were the main criteria of this study.
Material and Methods: A total of 20 patients were included in this prospectively randomized study (10 patients with and 10 patients without corneal ring). Follow-up examinations were performed 6 weeks, 4, 12, and 18 months postoperatively, including best corrected visual acuity and Orbscan corneal topography.
Results: The mean follow-up time is currently 18.9+/-2.8 months. The mean astigmatism (Orbscan) is 3.9 D in the group with ring and 4.0 D in the group without a ring. Spontaneous suture rupture occurred in five patients with corneal ring.
Conclusions: The use of the intrastromal corneal ring following penetrating keratoplasty caused no reduction of postoperative astigmatism. The reason for the spontaneous suture ruptures is unclear.