Retroprosthetic membranes in AlphaCor patients - Risk factors and prevention

Purpose: To report retroprosthetic membrane (RPM) formation in association with AlphaCor and identify risk factors for their formation and strategies for prevention and management. Methods: Review of AlphaCor data and case histories and literature review. Results: RPMs occurred with AlphaCor in 14 (9.3%) cases. We find significant associations with systemic risk factors (race, hypertension, diabetes mellitus) rather than ocular history, but perioperative management may also be related to risk of RPM development. Histology demonstrates a fibrovascular tissue resembling scarred corneal tissue. Similar histologic findings have been reported for other devices. Conclusion: Retrocorneal membranes and RPMs with earlier keratoprostheses have frequently been reported without specific identifiable causes. Diabetes is known to be associated with intraocular membrane formation. This study demonstrates that systemic factors affect the risk of RPM formation with AlphaCor. In cases identified as at greater risk of membrane formation, peri- and postoperative therapies such as steroids, non-steroidals, heparin or rTPA should be considered. In our series, several therapeutic and surgical strategies appear effective but recognizing patients at increased risk preoperatively and using preventive measures where indicated is likely to be key to minimizing the incidence of this complication.