Metalloproteinase-9 on the Ocular Surface of Patients With Implanted Boston Type 1 Keratoprosthesis

Abstract

Purpose: The aim of this study was to characterize the presence of ocular surface inflammation, using matrix metalloproteinase-9 (MMP-9) as a marker, on the ocular surface of eyes with implanted Boston keratoprosthesis type 1 (KPro). Methods: Patients with implanted KPro at a single tertiary center were recruited to assess ocular inflammation. MMP-9 was measured using the InflammaDry test in both eyes of each patient. The non-KPro eye served as the control. Rate of positivity of MMP-9 was compared between groups. Possible associations between ocular surface inflammation and the development of postoperative complications were evaluated using univariate statistical analysis. Results: Fifty eyes from 25 patients were included. The mean age was 50 years. Noninflammatory indications for KPro were predominant among patients. Eighty-eight percent of KPro eyes had a positive test for MMP-9 while only 25% of control eyes were positive (P < 001). The most common complications were retroprosthetic membrane, epithelial defects, and sterile corneal melt. The presence of a strong positive result was associated with a higher frequency of complications (80% of eyes) compared with a faint positive test (54%) and a negative test (33%). Conclusions: The KPro device seems to increase MMP-9 levels on the ocular surface. High MMP-9 levels may be associated with higher risk of complications. MMP-9 testing can be useful to assess subclinical ocular surface inflammation with a potential role in the postoperative care of patients with KPro.