Having cataract surgery

Cataract surgery

Cataract surgery usually takes about 30 minutes. You do not need to stay overnight and can leave hospital the same day.

It's usually done with local anaesthetic. This means you will be awake but you will not feel any pain.

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

Preparing for cataract surgery

To prepare, make sure you:

  • bring something to keep you entertained while you wait but leave valuables at home
  • bring with you a list of the medicines you take
  • have a trusted friend or family member escort you when you leave hospital. This is essential if you are having general anaesthetic or sedation, or surgery on both eyes
  • stop eating and drinking before surgery if you have a general anaesthetic
  • follow instructions if you have diabetes

Please allow half a day in our unit if your operation is under a local anaesthetic, and the whole day if your operation is under a general anaesthetic.

If you are having local anaesthetic, you need to be able to lie flat for about:

  • 30 minutes if you are having surgery on one eye
  • 1 hour if you are having surgery on both eyes

You also need to be able to keep your head still during the surgery, but can have a break halfway through if you are having both eyes treated. If you cannot do this, please talk to your nurse about this during your pre-assessment appointment.

Eating and drinking before surgery

If your operation is done using a local anaesthetic, you can eat and drink as normal before and after surgery.

If you are having a general anaesthetic, you cannot eat or drink anything (except water) for 6 hours before surgery. This is called fasting.

We give you clear instructions about if you need to fast and when to start fasting. It is important to follow the instructions. If there is food or liquid in your stomach during the anaesthetic it could come up to the back of your throat and damage your lungs.

Read more about having a general anaesthetic.

Your usual medicines

Do not stop any of your regular medicines before or after surgery (including eye drops), unless your surgeon asks you to.

If you are having a local anaesthetic, you should take your medicines as you usually would. If you are having a general anaesthetic, you should take your medicines with only a small sip of water.

If you take a water tablet (diuretic) in the morning, it might be better to take the tablet after surgery, instead of before.

If you take blood-thinning medicines (such as warfarin), you will need to have your INR blood test checked the week before surgery. If it is high, it might need to be repeated on the day of surgery. Depending on the result, we may need to reschedule your surgery.

Please bring a list of the medicines your take with you to the hospital.

If you have diabetes

If you are diabetic, you will be given instructions about taking your diabetic medicines before surgery.

Please bring a sweet drink with you to your appointment in case your sugar level falls low.

On the day of surgery

You should arrive at:

  • 7.30am if you have a morning appointment
  • midday if you have an afternoon appointment

Please come to the eye day case unit, 8th floor, North Wing, St Thomas’ Hospital.

If you are unable to attend, please call 020 7188 4308.

Our unit can be very busy at times. If you have a family member or friend with you, they might be asked to leave the unit and given a time to return to take you home. Or, they can leave their phone number and our staff will call them when you are ready to go home.

Time of your surgery

We cannot tell you in advance exactly what time your operation will be, as this depends on a number of different things on the day.

Please plan to be in our unit for half a day if you are having local anaesthetic, and the whole day if you are having a general anaesthetic.

During surgery

We do cataract surgery as day surgery and it usually takes about 30 minutes. We use local anaesthetic. You will have the local anaesthetic as eye drops, or as an injection around your eye.

You are awake but will not feel any pain.

You are not able to see properly during the operation, but you may notice bright lights or colours.

We ask you to keep your head still and look at a light while lying on a bed. You need to lie still during the operation. If you need to cough or adjust your position, please warn your surgeon.

We make small incisions (cuts) in the side of the eye and use small ultrasound probes. The energy from the ultrasound breaks up the cataract so it can be removed. This is called ‘phacoemulsification’ and does not involve lasers.

We replace your lens with an artificial lens.

Anaesthetic options

If you think that having the operation with local anaesthetic might be too difficult for you, speak to your medical team. It is possible to have:

  • general anaesthetic so you will be asleep during surgery
  • local anaesthetic with sedation so you will be calm and relaxed

However, because general anaesthetic has more risks, it is usually only offered in special circumstances.

Cataract surgery for both eyes

If you have cataracts in both eyes, they will usually be removed separately. You will have one surgery on one eye, and then once this eye is healed you will have surgery on the second eye. Usually, the second eye surgery can be done a few weeks after the first one.

It is possible to have both eyes treated on the same day (bilateral cataract surgery). This is not suitable for everyone, and so your surgeon will talk to you about this if it is suitable for you.

Bilateral cataract surgery is safe, and allows for a quicker recovery time from cataract surgery. This can be useful if your vision is affecting your work or other day to day activities, or if you have a high glasses prescription and surgery in one eye only would cause an imbalance.

After surgery

After your operation, you may have an eye pad and shield over your eye.

If you have surgery on both eyes, on the same day, your vision will be affected but you should be able to see well enough to walk safety. You will be taken back to the waiting area by a member of staff, and you will need a family member or friend to take you home.

Once you have recovered from the anaesthetic, you will receive:

  • eye drops
  • instructions about caring for your eye
  • details of your next appointment

You will then be discharged and can leave hospital.

Fit note for time off work

Before you leave hospital, you can ask for a fit note. The doctor will assess you and can issue a fit note to advise that you are:

  • "not fit for work" and you should have time off
  • "may be fit for work taking into account the following advice"

The hospital doctor will decide the length of time you should stay off work.

If you get a fit note while you are in hospital, you do not have to make an appointment with your GP for a fit note.

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

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