Anterior chamber intraocular lenses were implanted in phakic cynomolgus monkey eyes and followed clinically over two years. Significant observations included erosion and/or uveal envelopment of the haptic and a decrease in endothelial cell counts. There was good positional stability, no significant inflammation, initial ocular hypotension that returned to normal intraocular pressure, and no evidence of cataracts or cystoid macular edema.