Metalloproteinase-9 in the ocular surface of patients with implanted Boston type 1 keratoprosthesis.

PURPOSE

To characterize the presence of ocular surface inflammation, using matrix metalloproteinase 9 (MMP-9) as a marker, in 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 InflammaDry test in both eyes of each patient. The non-KPro eye served as 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 old. Non-inflammatory 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 to a higher frequency of complications (80% of eyes) compared to a faint positive test (54%) and a negative test (33%).

CONCLUSION

The KPro device appears to increase MMP-9 levels in 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 KPro patients.