The monofocal or standard IOL is the most commonly implanted lens and if you’re undergoing cataract surgery on the NHS, you will usually be offered this option.
A monofocal lens will only offer one fixed focus, whether that’s far, intermediate or near, although it’s usually used to achieve good distance vision. You will then likely need to wear glasses for reading or close work.
Multifocal IOLs are a more recent development in lens replacement and are specially designed to achieve good near, intermediate or distance vision all in one. They use different optical strengths across different areas of the lens and designs vary from bifocal lens similar to glasses to ones with concentric circles of different focus.
These can be a good option if you suffer from presbyopia prior to the development of cataracts and wish to reduce your dependence on glasses or contact lenses.
However, they can cause some minor night vision issues and aren’t suitable for all patients. They do not correct astigmatism.