Multifocal intra-ocular lenses.

Multifocal intra-ocular lenses (IOLs) are designed to overcome the lack of accomodation to provide useful distance and near vision. Reduced contrast sensitivity has been reported. Refractive IOLs produce two or more focal points depending on the refractive power of the portion of the lens crossed by the light. Diffractive IOLs are strictly bifocal; each point of the lens can create both a distance and near focus. Several clinical investigations show that multifocal IOLs can be used as an alternative to monofocal lenses. However, patient selection, realistic expectations, and adequate control of surgical procedures are necessary.