The visual acuity, bifocal capability and quality of vision were evaluated in 14 patients who had implantation of a 3M diffractive posterior chamber intraocular lens (IOL). Initially, four patients had an existing monofocal IOL in the fellow eye as controls. Ten of patients had the unoperated fellow eye as controls. Three of these patients subsequently had monocular IOL implantation, bringing the number of pseudophakic monofocal IOL control eyes to seven. All but two patients noted monocular diplopia; in three patients this was so intolerable that the diffractive lens was explanted and exchanged for a monofocal lens, following which the visual acuity improved by an average of two Snellen lines and complaints of monocular diplopia disappeared. Three patients had bilateral 3M diffractive lens implantation.