Cataract removal surgery
What is a cataract?
A cataract is the term used to describe cloudiness in the natural lens in the front of the eye. This can vary from a subtle opacity that causes glare and dazzle when driving to a totally white and opaque lens with severe visual impairment. The lens in the eye is really very similar to the sort of lens you would get in any camera. It focuses light onto the retina (film in the camera) and this is how you see.
What is the treatment?
There is no effective medical therapy for cataracts. Treatment involves a short surgical procedure to remove the cloudy lens and replace it with a tiny foldable lens implant that will take over the focussing of the eye.
Do I need cataract surgery?
If your optometrist has seen you and confirmed that you have cataracts you will probably have been referred to an eye specialist for assessment. An initial consultation will take about half an hour. This involves a thorough history and examination to establish whether you actually need cataract surgery at this stage. The eye will be carefully examined with particular emphasis on the general health of the eye including the state of the retina. Measurements of the eyeball will be taken with a laser to determine the precise power of the lens that will be needed to correct your sight.
Types of lens implant
Until quite recently all patients who had cataract surgery had a standard lens implant that nearly always corrected vision for distance. This meant that the distance vision without glasses was nearly always excellent but patients struggled to read or use a computer without the help of reading glasses.
In the last few years, lens implant technology has improved substantially and the decision about which sort of lens to use can be quite confusing. Options include monovision, where one eye is corrected for distance and the other for near. This strategy has been successfully used in contact lens patients for many years. However, it is not suitable for everyone. Other options include multifocal lenses which correct for near and distance at the same time. These lenses can be extremely successful but they don't suit everybody and can cause some optical side effects such as glare when driving at night.
The newer multifocals such as the Comfort lens aim to correct a bit of near vision without some of the side effects of the earlier multifocals. Often the Comfort lens will be combined with a bit of monovision for optimal results. Many patients have astigmatism (this is where the cornea, which is the clear window at the front of the eye is shaped more like a rugby ball than a football). Toric lens implants are designed to counteract the optical effects of astigmatism. They are very similar in appearance to a standard lens but are carefully rotated into a precise position during the surgery according to detailed calculations carried out beforehand.
Traditionally multifocal lenses were not suitable for anyone with significant astigmatism but even that has now been overcome with the arrival of multifocal toric lenses. So, the decision about the lens implant that you might choose is now more complex. Your consultant has long standing experience with all these types of lenses and will help guide you towards an option that will maximise the visual success of your surgery.
What does cataract surgery involve?
Cataract surgery nowadays is always carried out as a daycase procedure. In fact, most patients are only in the hospital for about two or three hours.
The vast majority of patients are done under local anaesthetic but general anaesthesia is also available if required. Even patients who are rather anxious about the prospect of having eye surgery whilst awake usually cope very well once they understand what is involved and that the surgery itself is essentially painless. However, if you are just plain 'terrified' by the prospect of being awake during an eye operation, then a general anaesthetic would be the kindest and safest option and can still be done as a day case. You would typically stay in the hospital for a period of around six hours.
On admission, your surgeon will come and see you again to run through any last minute questions you might have before your surgery. The pupil needs to be dilated for cataract surgery. This used to involve a lot of drops going into the eye and they could sting a bit. However, our surgeons tend to use a small pellet called a Mydriasert which is about the size of half a grain of rice and which is placed in the little 'cul de sac' behind the lower eyelid about half an hour before your operation. Once it is in position you cannot feel it and the pupil will dilate extremely well.
Once you are in theatre the eye will be anaesthetized. A few drops of anaesthetic are applied and the eye surface will become numb. At this stage a tiny nick is made in the conjunctiva and a small amount of anaesthetic solution is applied around the eye. This is done with a very tiny blunt metal tube called a cannula. It may be a relief to know that no needles are involved in this process! The vast majority of patients either feel very little when this is done or a few moments of mild discomfort. At that point the eye will become totally numb and 'the worst is over'. Patients who are extremely relaxed and not that anxious about having an eye operation can have their operation done with just anaesthetic drops. This is known as topical anaesthesia. The benefits of this are that the vision recovers much more quickly after the procedure and the eye remains completely white, without the temporary bloodshot appearance associated with the cannula method. The disadvantages are that, although there is no sharp pain, a certain amount of pressure may be felt during parts of the procedure and, because the optic nerve is not 'asleep', you will be able to see some bits of what is taking place.
The operation commences as soon as the eye is anaesthetized. A clear plastic drape is placed over the eye. This is to keep the area of surgery as sterile as possible and also to catch the water that is continuously flowing around the eye during the procedure. A bar with cool air flowing through it is placed above the mouth and nose to keep the drape off that part of the face. If you are worried that you might be claustrophobic please advise your surgeon who can then attach the drape to the microscope so that you are able to see out with the other eye. A nurse will usually be available to hold your hand throughout the operation if you would find this helpful. Should you have any concerns you can squeeze their hand and then the surgeon can pause and sort out whatever might be bothering you.
Modern cataract surgery has evolved tremendously over the last 20 years. The whole operation is performed through an opening of less than 3mm. This is about an eighth of an inch.
If you think of your lens as being like a 'Smartie' sweet, the procedure involves making a tiny circular opening in the coloured part of the Smartie at the front. The 'chocolate' is then broken into tiny pieces with an ultrasound probe and then removed from the eye.
You are then left with a very thin transparent capsule that formed the outer lining of the natural lens and it is into this space that the new lens implant is placed. Lenses nowadays are foldable so that they can be inserted through the tiny opening in the front of the eye. A typical lens is about the size of a baby's fingernail. This lens is folded over in half and now resembles a tiny pitta bread. The 'legs' that will stabilize it and hold it in place are folded over inside the 'pitta' and the lens is then placed inside a cartridge and very carefully inserted into the eye.
At this point the procedure is nearly over. The position of the lens is carefully checked and antibiotic solution is placed inside the eye.
Typically the surgery itself takes around ten minutes but the overall time in theatre is about 20 minutes.
After the operation you will return to the ward and usually have a cup of tea. As soon as you are ready you can go home. The vision will be very 'weird' for a few hours. Blurred, double vision and everything will seem very bright. This is mainly due to the large pupil but the anaesthetic also takes an hour or so to wear off. The eye may feel scratchy and slightly irritable for a couple of hours but normally settles pretty quickly.
There are no specific restrictions on physical activity after your operation. You should however take it fairly easy for a few days. Obviously you should not vigorously rub the eye for at least a couple of weeks and you won't be able to drive until the vision has settled. A day or so in most cases. Check that you can easily read a number plate at the required distance (about 25 yards) before driving.
You will be given two lots of drops to use after the operation. If you have someone who can do this for you, all the better, but the nurses on the ward can demonstrate the technique if you are going to be on your own.
You will usually see your surgeon a few days after your operation to check the eye and find out how you are doing, alternatively some patients may be discharged back to their optometrist and this will be discussed at your consultation.
When will I recover?
You should be able to go home a few hours after the surgery and you will need to use the prescribed eye drops and be careful not to rub or press on your eye. Your normal daily life can be resumed although you should avoid strenuous exercise for a couple of weeks.
Your vision should improve over the first 24 - 48 hours and we will normally see you again within the first week after the operation to check on your progress and provide any advice and support you need.
You should see your optician four to five weeks after surgery to check your requirement for glasses - this delay allows your eye to fully settle before being assessed. The operation is designed to ensure you have good unaided distance vision though it can mean that reading glasses may be needed depending upon your normal quality of vision.
What risks should I know about?
Cataract removal is a regularly performed operation worldwide and is considered to be quite safe. Most patients do not suffer any complications or side effects but we should mention those complications that can occur, even though it is in less than 0.1% of occasions. Other risks can include:
- Bleeding at the back of your eye which can disturb vision
- Some pain after the operation which can be helped by over the counter pain medication
- Infection inside the eye
- Tearing of the very delicate lens membrane that holds the new lens
- Retinal detachment
Although these conditions are potentially treatable, they could, in some very extreme cases, result in loss of vision in the affected eye.