SCANNING ELECTRON-MICROSCOPY OF INTRAOCULAR LENSES THAT HAD BEEN IMPLANTED IN DOGS

Scanning electron microscopy was used to evaluate changes on the surfa ces of polymethylmethacrylate (PMMA), silicone, and polyhydroxy-ethylm ethacrylate (HEMA) intraocular lenses (IOL) that had been implanted in the anterior chambers of the right eyes of 15 dogs. Five dogs receive d PMMA IOL; 5 dogs received silicone IOL; and 5 dogs received HEMA IOL . Twenty-eight days after surgery, the IOL were removed and processed for scanning electron microscopy. Nonimplanted IOL of each type were p rocessed identically for comparison. Implanted PMMA IOL had significan tly more debris and macrophages on their surfaces than did silicone IO L or HEMA IOL, Silicone IOL had significantly less fibrin deposition t han did PMMA or HEMA IOL. Silicone IOL had surface defects attributabl e to handling by surgical instruments. Implanted HEMA IOL had multiple pits that appeared to be caused by biodegradation.