MIRAgel: hydrolytic degradation and long-term observations.

Objective: To analyze long-term complications of hydrogel (MIRAgel; MIRA Inc, Waltham, Mass) explants.

Design: Institutional clinical study of a retrospective, interventional case series of patients. We included 415 patients with complete reattachment of the retina 6 months after surgery and up-to-date follow-up. Patients underwent ophthalmological examination at each visit (mean follow-up, 187 months), and 6 underwent computed tomography and/or magnetic resonance imaging. Main outcome measures included the MIRAgel explant removal rate, clinical manifestations related to removal, interval from the start of discomfort to removal, mean time from implantation to removal, culture yield of the removed elements, results of histological examination of the capsule surrounding the removed explants (12 cases), and micro-Fourier transform infrared spectroscopic analysis results of 3 recovered explants.

Results: MIRAgel explant removal was necessary in 27 (6.5%) of 415 patients who received MIRAgel material and in 27 (7.6%) of 357 patients who had had it for 7 or more years. Clinical manifestations were related to swelling of the MIRAgel material, with a mean interval of 15 (range, 6-22) months from starting symptoms to removal. The infrared spectroscopic analysis demonstrated the presence of carboxylic groups in 3 recovered explants that had swollen considerably.

Conclusion: Prompt removal of MIRAgel explants when discomfort starts should be considered to avoid increased incidence of complications.