Bifocal intraocular lenses (IOLs) have two focal points, providing clear vision at two distances, far and near distances. Patients choose this type of lens over a monofocal IOL when they wish to see clearly at additional distance, and become less dependent on visual aids. Bifocal IOLs allow you to see clearly and perform tasks such as reading and driving without glasses. However, you may still need to wear glasses for certain tasks in the intermediate-range (approx. 80 cm), such as computer work and cooking.
The biggest advantage of bifocal lenses is the possibility to become less dependent on glasses not only for nearby activities, but also activities requiring good far vision, such as driving. IOLs with two focal points enable you to engage in activities such as reading, sewing and other work up close without needing glasses. It means that you no longer have to switch between different kinds of glasses e.g. reading glasses and glasses for computer work, which can give you more freedom in your daily life.
If you are considering an option that allows you to additionally see objects clearly at the intermediate distance, you should discuss with your ophthalmologist if trifocal lenses are right for you. Read more about how trifocal lenses work.
Like with all innovative technologies, there are a few things to consider when choosing a bifocal lens. If you suffer from certain eye diseases, such as glaucoma, diabetic retinopathy, diabetic macular oedema, or macular degeneration, you may not be eligible for bifocal lenses. Discuss alternative options with your ophthalmologist if you suffer from any of these diseases.
One side effect connected with multifocal IOLs is a higher degree of visual disturbances and light phenomena (dysphotopsia), which are caused by the lens focusing light from multiple distances. These are normally perceived as:
Most people with multifocal lenses find these phenomena only mildly disturbing and get used to them over time. However, there is also a small group of patients who do not adapt to the lenses well or are very bothered by the glare and halos that may occur.
Decreased contrast sensitivity
Another consequence of multifocality is slightly reduced contrast and a less sharp image on the retina. This is due to the lens splitting light from different distances. Therefore, patients have to compromise a little bit on the image quality to gain the multifocal effect.