The traditional intraocular lens is the monofocal lens. It allows focusing at one distance, typically for distance. The patient must then wear glasses for intermediate distance vision and for reading. The evolution of the monofocal lens is the still monofocal but toric lens. This lens is also capable of correcting astigmatism, providing patients with excellent  visual acuity, potentially without distance glasses. More modernly, even more advanced lenses have been made available on the market:

• EDOF lenses: these spherical or toric lenses also offer good correction for intermediate distance, whereas for reading it is often necessary, though not always, to use reading glasses. These are lenses that extend the depth of focus by taking it up to 80-65 centimeters away. The intermediate distance is in fact extremely widely used in everyday life: think, for example, of the car dashboard, the satellite navigation system, the cell phone and other common activities such as eating, cooking, reading a score or looking at a shop window.Such lenses can evoke slight disturbances in the evening, such as modest halos around light sources.
• Multifocal Lenses-These lenses, modernly often with difractive geometry, allow focusing for both distance, intermediate distance, and near. Their design often involves concentric rings made in small steps on the lens surface, responsible for diffraction and consequent creation of multiple foci (far, intermediate and near). Indicatively, about 50 percent of the light is focused for distance and 50 percent for middle distance and near.
  

From the geometry and characteristics of the optics descend the two factors characterizing the use of multifocal lenses, namely, the need for good illumination especially for reading and the viewing of phenomena such as halos or rays around point light sources when in the dark.

Such phenomena are usually perceived as mild disturbances and tend to be ignored within a few months thanks to neuroadaptation processes. Not all people are candidates for multifocal lens implantation. The ideal patient is the person who wishes to emancipate himself or herself from the use of spectacles even for reading and is a positive person who understands and enjoys the exceptional nature of not using them (except at rare times) and therefore willingly accepts mild discomfort or a decline in the quality of vision especially in the evening. In contrast, professional drivers such as truck drivers or cab drivers or hypercritical people are not suitable for such a facility.