Choosing a Lens for Cataract Surgery: Monofocal, Toric, Multifocal and Monovision

Cataract surgery replaces your cloudy natural lens with a permanent artificial intraocular lens, or IOL, and the type you choose shapes how you see for the rest of your life; the main options are monofocal, toric, multifocal or EDOF, and a monovision approach¹. A monofocal lens gives excellent distance vision but usually means readers, while premium lenses aim to reduce glasses use across distances at the cost of more glare and haloes for some people².

This is the lens hub within cataract surgery, and the detailed comparisons branch from here: monofocal versus multifocal lenses, toric lenses for astigmatism and whether premium lenses are worth it.

What an intraocular lens actually is

During surgery, the surgeon removes the cloudy lens and inserts a folded intraocular lens (IOL) into the lens capsule, where it unfolds and stays permanently³. It does not need cleaning or replacing, and it does not cloud over again the way your natural lens did. Because it is permanent, the choice you make at the assessment is one you live with, which is why it deserves real thought.

Monofocal lenses: the standard choice

A monofocal IOL focuses at one distance, usually set for distance vision, so most people still need glasses for reading². It is the standard NHS lens and gives excellent, predictable distance vision⁴. The trade is simple and honest: superb clarity at one distance, readers for the rest.

This is the lens I chose. Both my eyes were set for distance, and I reach for readers for the newspaper without a second thought. The colours came back so vividly after surgery that the small inconvenience of glasses for close work never bothered me.

Toric lenses: for astigmatism

A toric IOL is a monofocal lens that also corrects astigmatism¹. Astigmatism is an irregular curve of the front of the eye that blurs vision at all distances, and a standard monofocal lens does not correct it. If you have significant astigmatism, a toric lens can deliver sharper uncorrected vision, though it still focuses at one distance, so reading glasses are usually still needed.

Multifocal and EDOF lenses: reducing glasses use

Multifocal and EDOF (extended depth of focus) IOLs are premium lenses that aim to reduce dependence on glasses across distances¹. The trade-off is real: they can mean more glare and haloes at night and do not suit everyone, and they are usually a private or extra cost². For someone who drives a lot at night, the night-vision effects matter; for someone who mainly wants to read without glasses, they may be a good fit.

Monovision: a different route to less glasses

Monovision sets one eye for distance and the other for near, using monofocal lenses, as an alternative route to less glasses dependence¹. The brain learns to favour whichever eye suits the task. It works well for some people and not at all for others, so it is usually trialled or discussed carefully, and it avoids the night-vision effects associated with multifocal lenses.

How the right lens is decided

Premium lenses reduce glasses use for some people but are not automatically better; the right lens depends on your eyes, lifestyle and tolerance of night-vision effects². The choice is made at the assessment, where your eyes are measured and your priorities discussed⁴.

For me, the decision came down to what I actually do: I wanted reliable distance vision and was entirely happy to keep readers, so a monofocal lens was the obvious choice. Someone with a very different life and a strong wish to be free of glasses might weigh it differently, which is exactly the point.