Titanium back plate for a PMMA keratoprosthesis: Clinical outcomes

Background/Purpose: To compare the rate of retroprosthetic membrane (RPM) formation in Boston Keratoprosthesis (BKPro) with polymethyl methacrylate (PMMA) versus titanium backplates. Design: Retrospective comparative chart review. Methods: Multicenter study population: a total of 78 eyes with keratoprosthesis implants with either PMMA or titanium backplates were included in the study. To be included in the study, all subjects had to have completed a minimum of 6-month follow-up period. Incidence of RPM development at 6-month postoperative period was noted across the study population. PMMA and titanium backplates were then compared by their rate of association with subsequent RPM. Results: Twenty-three out of 55 eyes (41.8%) with PMMA backplates and three out of 23 eyes (13.0%) with titanium backplates had developed an RPM at 6 months after implantation. The titanium backplates were associated with significantly less RPM formation than PMMA backplates (p=0.014, Chi-square test). Conclusions: Titanium seems to be associated with less RPM formation than PMMA when used as a material for the BKPro back plate.