APR 12, 2012
Many countries, including Canada, are experiencing a critical shortage of fresh corneal donor tissue. The use of frozen corneal grafts, such as those used in tectonic grafts, would allow for greater availability of donors.. That is why the authors chose to conduct this prospective study to determine the feasibility of using the Boston keratoprosthesis (KPro) with frozen corneal donor tissue.
They randomized 37 patients to KPro surgery with fresh or frozen corneas as carriers. All surgeries were performed by the same experienced surgeon at a single center in Canada. The mean follow-up was 9.65 months.
Median preoperative visual acuity was counting fingers in the fresh cornea group and hand motions in the frozen cornea group. Median postoperative visual acuity was 20/150 in both groups. Both groups had a 100 percent retention rate.
Inflammation and retroprosthetic membrane formation were the most common complications, with similar rates between the groups. No leaks, tissue necrosis, melts or infectious endophthalmitis cases were encountered.
The authors note that most of the patients had nonautoimmune and nonchemical preoperative diagnoses and, as such, lower baseline risk for severe complications, such as melts. Furthermore, the 100 percent retention rate could be explained by preoperative selection of patients from the most favorable diagnostic categories of the well-known prognostic hierarchy for Boston KPro type 1 surgery.
They conclude that although this study demonstrates excellent device retention compared with previous reports, its limitations lie in its relatively small sample size and short follow-up period.