Cataract surgery

In your eye you have a lens behind the coloured part of your eye (iris). The lens focuses light so you can see objects at different distances.

The lens is a clear colour when you are young, but becomes cloudier and more yellow as you get older. This clouding of the lens is called a cataract. Cataracts can affect one, or both eyes.

Over time, the cataract can:

  • make your vision blurry
  • make you more sensitive to light

You might find that you are needing to change your glasses prescription more than usual.

Sometimes cataracts develop very slowly. Your optician that notices them during a routine eye test.

Cataract surgery replaces your cloudy lens with an artificial lens. This procedure takes about 30 minutes and is done under local anaesthetic.

Once the cataract is removed you should be able to see more clearly. How well you see colour may also improve.

Patient: Before the operation, I noticed that things were getting dimmer, blurred and yellowish. When the word 'cataract' was mentioned I thought they can correct that, I'm sure they can correct that. So I was a little bit relieved at the time. The three months before my operation, it started to progress really fast and it got really scary, I just then thought, get me sorted. On the day of the surgery, I took my tablets as normal and I came to the eye department at St Thomas'. 

Nurse: Hello, is this Mrs Bagnall? Good afternoon. 

Patient: A nurse did some checks to make sure it could all go ahead. I met the surgeon. 

Surgeon: Are you happy with that? 

Patient: I am.

Surgeon: Lovely, OK. Thank you, lovely. And then just keep looking straight ahead. 

Patient: The nurse brought me into the operating theatre. They used lots of drops to numb my eye, it stung a bit but it wasn't too bad. They told me if I wanted to move or cough, I had to warn the surgeon. They put a drape over my face and then a clip to stop me blinking. It was a bit uncomfortable but it didn't hurt. 

Surgeon: Keep your head really still for me.  

Patient: They streamed water over my eye, they told me to look into the light for the whole operation. 

Surgeon: You're staying really still for me, that's great. 

Patient: All I could see was lights and shadows.

Surgeon: OK, lovely, so the cataract's out now, I'm just going to get it ready for the new lens.  

Patient: When I was in theatre, I felt the pressure but I didn't feel any pain. I was quite surprised and then everything stopped and it's like, is that it? After the operation they put a shield over my eye. I had a rest, then they showed me how to care for my eye and we booked in my next appointment.

I expected to have some pain but everything was normal and I still can't believe how quick and how good it is. Today my eyesight is worse close up but as long as I wear reading glasses I'm fine. Other than that, my vision is great. So very, very happy, I'm very happy I did this. 

Who can have cataract surgery

Everyone develops a degree of cataract as they get older. However, it can also happen at a younger age. This might be because of:

  • an injury to the eye
  • medicines (such as steroids)
  • long-term illnesses such as diabetes

Some people are born with cataracts (congenital cataracts).

A cataract itself is not harmful to your eye, so you should only have surgery when you feel the cataract is starting to affect your vision. In the early stages of a cataract, often a change in glasses prescription is enough.

With modern surgical techniques, we can perform surgery at any stage when the cataract is affecting your daily life.

The decision to have cataract surgery depends on how your vision is affected, and if the benefits outweigh the small risks associated with having surgery.

If you are having problems reading, using a computer or driving, you might want to consider surgery. If you are not concerned about your vision, then you might want to wait and have regular eye tests.

Having surgery

Cataract surgery is done as day surgery and usually takes about half an hour. It's done under local anaesthetic, so you are awake but your eye will not feel any pain.

We remove the cataract and replace your lens with an artificial lens. This is made of plastic and stays in your eye forever, only rarely needing replacement.

We take measurements before the operation to help us decide which lens strength is right for you. Usually, we aim to make you glasses-free for distance. This means you only need glasses for reading. However, there is a chance you will need glasses for both distance vision and reading after surgery, particularly if you have a history of astigmatism or an irregularly shaped eye.

If you have had previous laser refractive surgery, please remember to tell the doctor as it can affect the calculations for the lens replacement after cataract surgery.

Read more about having surgery and how to prepare.

Risks of cataract surgery

Cataract surgery is usually very successful. Over 95 out of 100 people notice an improvement in their vision after surgery. It is important to be aware that there is always a risk of complications with any type of surgery. If you have pre-existing conditions (such as previous injury, or surgery) this might mean your eye is at higher risk. 

Your medical team will talk to you about all the possible risks, and how they might affect you, before you have surgery.

Risks during surgery

Some of the possible complications during surgery include:

  • bleeding inside the eye, though this happens in less than 1 in 1,000 people
  • damage to other structures of the eye (such as the capsule surrounding the lens) which can sometimes affect your vision
  • incomplete removal of the cataract, which might mean you need surgery again in a few days
  • part of the cataract falling into the back of the eye

Some of these complications can be dealt with during surgery, or just after.

Complications after surgery

Possible complications after surgery include:

  • bruising of the eye or eyelids
  • swelling or redness (inflammation)
  • severe infection, which can sometimes lead to vision loss
  • fluid in the layer at the back of your eye (retina)
  • the retina becomes loose, which will need surgery to repair
  • incorrect strength of artificial lens put in
  • clouding of the membrane behind the lens

These complications can sometimes happen even if the operation itself is carried out perfectly.

Many of these complications are manageable, although it may mean you need other treatments and it takes longer for you to recover.

More surgery is needed in approximately 1 in 100 cases.

The most serious complication is the risk of loss of vision, which may be temporary or permanent. The chance of severe or complete permanent loss of vision in the operated eye is less than 1 in 1,000.

In approximately 1 in 10 cases, the membrane behind the artificial lens can become cloudy making your vision more blurred again. If this happens, laser treatment may be needed sometime after surgery.

Support and information

Royal College of Ophthalmologists has information about cataracts that you might find helpful.

RNIB gives details on how to obtain their cataract information in audio format. 

Resource number: 3096/VER5
Last reviewed: November 2022
Next review: November 2025

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