You will be booked in for an initial consultation, where your vision will be measured and a check will be carried out to confirm the presence of the cataract. In many cases, your optometrist will have referred you, and will send a report. This information is extremely helpful for the surgeon and can assist his decision making in terms of the best option available for you, for example reducing the need for glasses after surgery. It is also important to rule out any other eye diseases.

Your GP can also detail other medical conditions, and it is useful to have a full list of all medications that you are currently taking. You will have the cataract operation explained to you and have a chance to ask any questions you may have.

Before surgery, a non-invasive test is carried out of both eyes. It is painless and lasts about 20 minutes. The test measures the dimensions of the eyes. Formulae are used to calculate the strength of the lens implant.

No, you will have two separate operations. The second one will be scheduled when recovery from the first is complete. It is very rare in the USA or the UK to operate on both eyes at the same time (as there are concerns about the risk of introducing infection to both eyes).

You will need to report to the hospital 2-3 hours before surgery. You will report to the nursing staff who will take a medical history, record any medications you take, and enquire about any allergies. Your blood pressure will be measured, and dilating drops will be put in the eye – these dilate the pupil to allow the surgeon to access the cataract. Mark will visit you, and answer any additional questions you may have. You will also be asked to sign a consent form, and Mark will mark the forehead above the eye to be operated on. You will then be asked to change into a gown.

Cataract operations are generally carried out under local anaesthetic. This is very safe and the recovery time from local anaesthetics is faster. The anaesthetist will place some local anaesthetic underneath the conjunctiva around the eye. The anaesthetic injection is generally felt as a small sting – a recent survey of patients at Moorfields Eye Hospital found that two-thirds of patients reported little or no discomfort. The local anaesthetic also paralyses the eye, so that you can’t see anything out of it while you’re being operated on. The eye will remain numb for about six hours, so there is no need to be concerned if surgery is delayed slightly. Occasionally, for very straightforward cataracts, local anaesthetic drops are used. The recovery time from these is even faster than for injected local anaesthetic.

Very anxious patients can be given some sedation as a intravenous injection: this makes you feel relaxed and sleepy during the operation, although you will still be awake.

You will be helped to lie flat on the operating table, made comfortable and your head will be supported. Sterile cloths will be draped around your face, covering the eye not being operated on. You may feel your eye being cleaned with cold fluid. Air will be gently blown towards your face through a pipe – this is to ensure you can breathe easily.

As the eye is anaesthetised, you do not have to worry about keeping the eye still, or blinking, as the eye is paralysed in any case. You will see little out of the eye being operated on due to the local anaesthetic, although some patients report sparkling lights or psychedelic colour patterns.

It helps if you can keep still during the operation and try not to speak. If you need anything you will be told to raise your hand. You may feel water running down the side of your face – this is just a salt water solution that the surgeon uses to keep the eye moist. You will hear the doctors and nurses moving around and the sounds of the equipment working. Music is often played in the operating theatre to help relax the patients. One famous eye surgeon of our acquaintance refused to operate unless Meatloaf's "Bat out of Hell" was playing!

People worry about this – but you will not be able to see the instruments coming towards your eye. You will see very little out of the operated eye due to the anaesthetic which has been administered. In addition, your other eye will be covered with a sterile transparent drape which is slightly frosted (see picture) – so you won’t see instruments out of your other eye, either.

Patients worry about this, but it does not matter as the eyeball being operated on is paralysed temporarily by the anaesthetic. You can blink your other eye as normal.

Mr Westcott explains what he does during cataract surgery:

“The modern operation for removal of cataract is called phakoemulsification. After the anaesthetic has been placed, I will insert a small instrument (speculum) in the operated eye to keep the eyelids open. You do not need to worry about blinking or moving the eye, as the eye will be anaesthetised. I then use a microscopic surgical instrument to make an incision into the cornea and to remove the cataract using a phakoemulsification probe. This probe uses ultrasound energy to liquidise the lens, which is then safely removed. Once the cataract has been removed, I will then insert the lens implant. This is a clear replacement lens which may be made out of an acrylic or a silicone material. The implant sits within the capsular bag. This is a very thin membrane which surrounds the original lens. Once the implant has been placed, the instruments are removed. We do not usually need to place any stitches, although occasionally, this may be necessary. Antibiotic is injected around or inside the eye.”

You will have a patch on your eye after the surgery, and patients are asked to remove this shortly after waking up on the following morning. Most patients are given a tablet of Diamox once they return to the ward (acetozolamide) to keep the pressure down in the eye.

You can go home after one to two hours after surgery. Most patients, sensibly, like to have a cup of tea and a light snack or sandwich. You should allow some time for your post-operative drops to be prepared in pharmacy, and for the nurse to go through these drops with you.

It’s a good idea to have a friend or relative with you to help you home. You will have a patch over one eye, which you will be adjusting to, and you may have been given some sedation for surgery. Public transport can be used, but for the reasons given above most patients prefer to leave hospital via car, minicab or taxi. Long journeys are best avoided.

Occasionally patients are seen the day after surgery – this is decided once surgery has taken place. You should be prepared to be able to return to the hospital the next day if asked. Patients who live a long way out of London should make plans that allow for this (either stay overnight in hospital, or in a hotel, or with a friend or relative). Please let us know if this is likely to cause problems and we can work out how best to accommodate your situation.

"You will receive drops or a pellet to dilate the pupil. If you are having femtosecond laser assisted cataract surgery, you will then be asked to lie flat on a couch. I will position the head carefully and some anaesthetic drops are instilled. I carefully place a small suction cup which engages the eye. You will feel some pressure on your eye because of the vacuum but it is not painful. I then perform some scans of the eye (this takes less than one minute), and following this apply the laser for about 20 - 30 seconds. You will see a kaleidoscope of red and green lights, which some patients have likened to the "Aurora Borealis"! After the laser has finished, I will release the cup on the eye (you will feel a little water running down the side of your face).

You will notice that the vision is very blurry in the treated eye after the laser and this is quite normal. Then the nurse will take you down to the operating room where the operation will continue

Patients who are not having femtosecond laser assisted cataract surgery will go straight into the operating theatre, where I will insert a small instrument (speculum) in the operated eye to keep the eyelids open once the anaesthetic has been administered.

You do not need to worry about blinking or moving the eye, as the eye will be anaesthetised. I then use a microscopic surgical instrument to make an incision into the cornea. The cataract is removed using a phakoemulsification probe. This probe uses ultrasound energy to liquidise the lens, which is then safely removed. Once the cataract has been removed, I will then insert the lens implant.

This is a clear replacement lens which may be made out of an acrylic polymer or a silicone material. The implant sits within the capsular bag. This is a very thin membrane which surrounds the original/ens. Once the implant has been placed, the instruments are removed. We do not usually need to place any stitches, although occasionally, this may be necessary. Antibiotic is injected around or inside the eye."