Gurpal Virdi, MD

Cataract surgery › When to have surgery

When is it time for cataract surgery?

First sign
Glare and halos at nightoften before anything looks blurred
The test
Does it interfere with your lifedriving after dark, reading, TV, work
On a chart
No number decides itand it need not be advanced
If you wait
Vision keeps decliningand a denser cataract is harder to remove

There is no number on a chart that decides this on its own. The decision comes down to one question, and this page is about how to answer it.

What a cataract usually looks like first

Often glare and halos around headlights at night, before anything looks blurred. Many people also notice their glasses prescription stops settling, changing more often than it used to, and that reading takes more light than it once did. The lens you are born with is clear; with age it gradually clouds, and that cloudy lens is a cataract. A clear lens focuses light to a point on the retina. A cataract scatters it instead, which is why the trouble usually shows up as glare and haze before it shows up as blur.

The one question

  1. 1Notice

    Glare and halos at night. A prescription that keeps changing. Reading that needs more light than it used to.

  2. 2Ask

    Is it interfering with something you actually do: driving after dark, reading, watching television, working?

  3. 3Decide

    If yes, it is time. No number on a chart decides this on its own, and a cataract does not need to be advanced to be worth removing.

What happens if you leave it

Vision keeps declining, and a cataract left long enough will eventually take useful sight, though that takes years. A denser cataract is also technically harder to remove, which raises the complication rate somewhat. Neither point is a reason to rush, but waiting is not a neutral choice either.

What the operation involves

The cloudy lens comes out and a clear intraocular lens goes in, sitting in the same place with your prescription built into it. You are awake but comfortable. The operation itself usually takes under ten minutes, and most people are back to ordinary activity the next day. Recovery, day by day.

Before the consultation

The measurements that decide your lens are only as good as the surface they are taken through, and you can improve that surface yourself before you arrive: preservative-free artificial tears four times a day for two weeks beforehand, warm compresses nightly, and out of contact lenses for at least a week. Expect dilation at the visit, a full set of scans, and a conversation about refractive target before any lens is chosen. Why each of those matters.

This is one part of the full guide. Cataract surgery and intraocular lens (IOL) selection covers the lens choice, the measurements behind it, the risks with their numbers, and a vision simulator.

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Medically reviewed by Gurpal Virdi, MD, refractive and cataract surgeon · Last reviewed: 27 September 2026

Educational information, not medical advice. Discuss your specific eyes with a qualified ophthalmologist.