Pseudoaccommodation with the 3M diffractive multifocal intraocular lens: a refraction study of 52 subjects

A refraction study was performed of 52 pseudophakic subjects implanted with a 3M diffractive intraocular lens (IOL). Twenty patients implanted with conventional monofocal IOLs from 3M were used as controls. The refraction for distance and near was determined, corresponding to the refractive (distance vision) and diffractive (near vision) foci. Pseudoaccommodation amplitude was measured relative to the variation of visual acuity as a function of "fogging" obtained with plus and minus lenses over any required spherical cylindrical power. Results showed that the 3M diffractive IOL acted as a bifocal lens in all subjects except those whose IOLs had decentered markedly. The dioptric range allowing good vision for distance and near is much wider with the diffractive IOL than it is with a monofocal IOL. Almost perfect vision, and the satisfaction of the patients, was achieved when the distance refraction was near to emmetropia and astigmatism was minimal. However, hyperopic biometric inaccuracies were less disturbing than myopic inaccuracies.