Extended Depth of Focus (EDF) and Multifocal Lenses
The Multifocal (ReSTOR and ReZOOM) and Extended Depth of Focus (Symfony) lenses are advanced technology lenses that are designed to minimize your dependence on glasses providing acceptable vision at more than one distance. The goal of these lenses is to allow you to see more like you did when you were younger and did not need bifocals.
The Multifocal and EDF lenses provide a greater depth of focus than the standard monofocal lenses. These lenses can be associated with side effects including glare, halos, and loss of contrast sensitivity. These side effects are especially pronounced with the higher power multifocal lenses (more powerful near focus) such as the ReSTOR 4.0. The higher power multifocal lenses can also be associated with a gap in clarity between distance and near. In general, the higher the power of the multifocal, the greater the side effects.
Some people are barely aware of these side effects. For others, glare and halos are quite noticeable. If you haven't done so already, please review the Four P's to see whether it is likely that you are a good candidate for multifocal lenses.