Cataract Surgery: What It Is, When You Need It, and What to Expect

Cataract surgery removes the eye’s cloudy natural lens and replaces it with a clear plastic intraocular lens that stays in permanently; it is a day case, usually under local anaesthetic, with the operation itself taking about 15 to 30 minutes per eye, and around 9 in 10 people achieve improved vision afterwards¹. It is one of the most common and most successful operations performed, and it is the only proven treatment for a cataract, since the clouding cannot be cleared with drops or glasses².

This is the pillar that ties the whole topic together. If you are still at the start, read what is a cataract and cataract symptoms first. From here, each section below links to a deeper guide on that step.

What cataract surgery is

Cataract surgery removes the cloudy natural lens and replaces it with a clear plastic intraocular lens (IOL) that stays in the eye permanently¹. The standard technique is phacoemulsification, often shortened to phaco: through a tiny self-sealing incision of around 2 to 3 mm, usually with no stitches, an ultrasound probe breaks the cloudy lens into fragments and removes them, and the folded IOL is inserted into the lens capsule where it unfolds².

A newer option, laser-assisted surgery (FLACS), uses a femtosecond laser for some steps but is more expensive and has not been shown to give better outcomes than standard phaco for routine cases³. We compare them fully in laser vs standard cataract surgery, and the step-by-step method is set out in how cataract surgery works.

When you need it

There is no fixed level of cloudiness that triggers surgery and no need to wait until a cataract is ripe, which is an outdated idea³. Surgery is offered when the cataract affects daily life: driving, reading, work, hobbies, or falls risk.

The decision is shared between you and your surgeon, weighing how much your vision limits you against the small risks of surgery⁴. For help with timing, see when to have cataract surgery and who needs cataract surgery. Everything starts with a proper cataract assessment.

Choosing your lens

The implant choice shapes how much you will rely on glasses afterwards. A monofocal (standard) lens focuses at one distance, usually set for distance vision, so most people still need glasses for reading; it is the standard NHS lens and gives excellent, predictable distance vision¹. A toric lens is a monofocal that also corrects astigmatism, while multifocal or extended depth of focus lenses aim to reduce glasses use across distances but can cause more glare and haloes at night and do not suit everyone².

Premium lenses reduce glasses use for some people but are not automatically better. Our detailed guides cover choosing a lens for cataract surgery, monofocal vs multifocal lenses, and whether premium lenses are worth it.

On the day and recovery

Cataract surgery is a day case, one eye at a time, usually under local anaesthetic with numbing drops and the patient awake¹. Most people go home the same day and need someone to take them. On the day the eye may be gritty, watery and sensitive to light, with vision blurry at first that clears over the next day or two, and a clear shield is worn at night for about a week.

Eye drops (antibiotic and anti-inflammatory) are used for about 2 to 4 weeks on a tapering schedule¹. Most people notice clearer, brighter, less yellow vision within days, with vision settling over a few weeks and new glasses prescribed around 4 to 6 weeks². The two eyes are normally done on separate visits, commonly a few weeks apart. See what happens on the day of cataract surgery, cataract surgery recovery, and having the second eye done.

When my turn came, the operation on my first eye was over before I had finished worrying about it, and by the next morning the difference in brightness was startling. I had the second eye done a few weeks later, and only then did I realise how yellow and dim everything had been for years.

Risks and what can go wrong

Serious, sight-threatening complications are uncommon: the risk of a serious complication that threatens sight is often quoted as roughly 1 in 1,000, varying with the eye and any other conditions¹. Around 9 in 10 people achieve improved vision, assuming no other eye disease, which is why globally the operation is so valued in reversing avoidable blindness⁵.

The most common later issue is posterior capsule opacification, where the capsule behind the implant clouds; it is not the cataract coming back and is fixed in minutes with a painless YAG laser treatment in clinic². For the full picture, read cataract surgery risks and complications and posterior capsule opacification.

What it costs

On the NHS, cataract surgery with a monofocal lens is funded when clinical criteria are met; premium lenses and faster private routes are not covered³. UK private surgery is commonly roughly £2,000 to £3,500 per eye with a standard lens, more with toric or multifocal lenses. In the US, Medicare and most insurers cover medically necessary cataract surgery with a standard lens, while self-pay is often around $3,500 to $7,000 per eye, with extra cost for premium lenses².

Prices vary widely by country, lens choice, and what the quoted package includes. For a full breakdown see how much cataract surgery costs, and to weigh the value see is cataract surgery worth it.