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Phacoemulsification cataract surgery

These notes are a guide to your cataract surgery. They may not cover every point you want to know. If you have any more questions or uncertainties please do not hesitate to ask.

What is a cataract?

The eye can be likened to a camera. Light enters the eye through the clear cornea and is focused onto the retina by the lens. The lens is surrounded by an elastic capsule. A cataract is clouding of the lens inside the eye. Cataract is not a skin growing over the eye.

What causes cataract?

The commonest form is part of the normal age changes in an otherwise healthy eye. Cataract can also occur as a result of injury, inflammation inside the eyeball, diabetes or the use of long term steroid medication. Cataracts can also occur in newborn babies as a fault of development. Cataract is not caused by overuse of the eyes or bad lighting. People differ in the age at which cataracts start and the rate at which they progress.

What are the effects of cataract?

When the lens of the eye becomes cloudy the image formed on the retina is not as clear. This results in blurred vision. Colours may lose their normal intensity and objects appear less bright. Some types of cataract make you more sensitive to bright lights with glare and dazzle, especially a problem when driving at night. Occasionally you may see two or even more images of an object out of one eye. The development of cataract can make you more short-sighted and lead to the need for frequent change of glasses. Cataract tends to progress and lead to a gradual deterioration in vision.

When do I need an operation?

Basically when you are noticing a problem with your vision that is interfering with your life-style. People differ at the stage when they request an operation. If you do a lot of reading or fine work you may want your operation at an earlier stage than someone who spends most of their time outdoors. As surgery is becoming more advanced we tend to operate earlier than ten to fifteen years ago. You do not need to wait for the cataract to become “ripe”. Cataracts can be removed at any stage.

You need to balance of risks of cataract surgery (see later) against the benefits before deciding to go ahead with surgery.

What is phacoemulsification?

Recently there have been improvements in the technique for cataract removal. The most modern technique available today is called phacoemulsification. This uses ultrasound energy to break up or emulsify the lens inside the eye. The use of ultrasound allows the cataract to be removed through a very small incision. This means that the eye heals quickly and with minimal distortion (or astigmatism). The incision is much smaller than that used previously; the wound is stronger and glasses can be prescribed at an earlier stage.

How is the cataract removed?

Before the operation drops will be put into the eye to make the pupil of the eye larger. The surgeon looks through a microscope during the operation. A small cut is made into the eye at the edge of the cornea (the clear window of the eye). This cut is 2.8 mm in width. Very fine forceps are then introduced into the eye and a circular tear in the elastic capsule of the lens is made. A probe that delivers ultrasound is then introduced into the eye and dissolves away the cataract leaving the elastic capsule behind. The capsule is cleaned and then an intraocular implant is inserted into the capsule to take the placed of the natural lens. A foldable lens is usually used which can be put into the eye through this tiny incision. The lens unfolds inside the eye to its normal shape. Often no stitches are required as the wound is constructed in such a way that it is self-sealing. Sometimes however the surgeon may insert some stitches to make the wound more secure.

How long does the operation last?

Between 15 to 45 minutes depending on the hardness of the cataract. Your face will be covered by a special drape, which has a bag on the side to collect the fluid that is used during the operation. Don’t worry if you feel some of the fluid on the side of your face or running down into your ear. The drape is held away from your face by a pipe that delivers oxygen under the sheet so you will have no difficulty breathing.

Why does the surgeon use an implant?

The natural lens of the eye focuses light onto the retina. After the cataract has been removed an artificial lens implant is needed to do this. Before implants were used very thick glasses were needed after surgery to give clear vision. The implants are made of acrylic plastic. They are inert and are very unlikely to cause inflammation inside the eye. Implants have been used for many years now and no major long-term problems have occurred.

Will I need to stay in hospital overnight?

Not usually; most surgery is now performed as a day-case. You will need someone to take you home and bring. If you do not have anyone who can do this we may be able to organize this for you. We do not recommend using public transport.

You may be asked to come for a pre-operative assessment some time before your operation. This is usually conducted by a nurse. He or she will ask you questions about your general health. Please bring all your tablets and medications with you. Measurements of the eye are taken so that the implant strength can be calculated (see later). You will have ample opportunity to ask questions at this visit.

What kind of anaesthetic will I need?

The operation can be performed under a local or general anaesthetic.

Local anaesthesia

98% of patients have surgery under local anaesthetic. You are awake for this kind of anaesthetic. They eye is numbed by an injection using a blunt tipped canula so the eye cant be damaged by a sharp needle. This stings a little but is not usually too uncomfortable. The anaesthetic injection also affects the muscles that move the eye around so that the eye is still during surgery. The vision will be temporarily blurred so you will not see the surgical instruments during the operation.

During the operation your pulse and breathing will be monitored by an instrument on your finger. A nurse will hold your hand during the operation and you can squeeze her hand if you are uncomfortable or feel about to cough. The surgeon can then stop what they are doing and make you comfortable again before the operation. During the operation you will feel the surgeon’s hands resting lightly on your forehead or cheek. You will hear noises made by the instruments used to remove the cataract and you will hear the doctors and nurses talking quietly. Try to relax. As the operation is very delicate we ask you not to talk during the surgery.

General Anaesthesia

Some people prefer to go to sleep for their operation. You may still be able to go home the same day if you are up and have had something to eat and drink. Modern general anaesthesia is very safe but if you have other medical problems such as a bad chest or heart disease your surgeon may recommend a local anaesthetic.

The choice if an individual one and you and your surgeon or anaesthetist will decide together.
Patients having a general anaesthetic should not eat for six hours before the operation. You may have clear fluids up to two hours before the operation (not containing milk). You do not need to fast before a local anaesthetic but please avoid a heavy meal before your operation. Please take your medications as normal. If you are diabetic and having a general anaesthetic you may be asked to omit your diabetic tablet or insulin on the morning of the operation. Again you will be given full details before the operation; if you are unsure do not hesitate to ask.

What happens following the operation?

The eye will have a plastic shield taped over it immediately following the operation. This can be removed the following morning. You will be asked to return to have the eye examined a week or so after the operation. Drops are prescribed four times a day for a month. The drops help to reduce inflammation and allow the eye to settle down quickly. The eye is not usually uncomfortable although you may experience mild irritation for a few days.

What can and can’t I do after the operation?

You can get back to your normal routine within a couple of days. There are no restrictions regarding reading or watching TV. You cannot damage your eyes by using them. You should avoid rubbing or touching the eye for a couple of weeks. When washing, gently wash around the eye using a clean flannel or cotton wool and then dab dry avoiding pressure on the eye. Have your hair washed with your head leaning backwards. You should avoid heavy lifting or strenuous exercise for two weeks. You can bend down as normal. It is wise to avoid swimming for a couple of weeks. If you have sedentary job you can back to this when you feel ready, usually after a day or two. If you have a manual job it is better to have a couple of weeks off work.

What about glasses?

Glasses can be prescribed once the eye has healed. This may be anywhere between three and four weeks after the operation. You can get your new glasses as soon as one week after the operation although there is a chance that they may need to be changed again as the healing process continues. Again you will be able to discuss this with your surgeon or optometrist.

Will I always need glasses?

Before the cataract is removed the length of the eyes and the curvature of the front of the eye (the cornea) are measured. This allows the surgeon to calculate the strength of the implant that will be inserted into the eye. The surgeon usually chooses a strength that aims to give you clearest vision in the distance. Some people may not therefore need distance glasses in many situations, although for clearest possible vision glasses will improve fine detail. Even if the distance vision is good without glasses you will need glasses for reading and close work.

If you are short-sighted or long-sighted before the cataract is removed, this may be reduced again by choosing an implant of appropriate strength. Patients with astigmatism are likely to need glasses for all distances after the operation unless a special astigmatism correcting implant is used.
In any biological situation there is inevitably some variability and unfortunately the strength of glasses needed cannot be guaranteed.
If you are unexpectedly long or short-sighted after the operation this can often be dealt with by putting an additional lens implant in or exchanging the original implant.

Freedom  from Glasses (Multifocal lens implants)

Recently there have been advances in intra-ocular lens design and the aim now can be to give patients freedom from glasses for both near and distance. These are called multifocal intra-ocular lenses. Lens implants are also available to treat astigmatism. Multifocal lens implants are not available soon the NHS but are available through self funding or possibly private insurance. See section on multifocal lens implants.

What are the risks?

No surgical operation has 100% success rate. Fortunately modern phacoemulsification cataract surgery has a low rate of complications. Most complications can be successfully managed.

The chance of the vision not being as good after the operation as it was before is in the region of 1 in 100. There are various reasons why the operation may not be a success. These include clouding of the cornea, cystoid macula oedema (inflammation of the central retina), retinal detachment, bleeding inside the eye and infection (1 in 1000) Sometimes there is a tear in the bag which holds the lens in place during the operation. This often results in the jelly behind the lens (vitreous gel) coming forward and this will need to be removed at the time of surgery. If this occurs, stitches are usually needed to close the wound and the procedure takes longer than usual. Very occasionally part of the cataract can fall backward into the eye and require further surgery to remove it at a later date. If this occurs the surgeon may elect not to put an implant in although this can usually be done at a later date.

My doctor said that he could not guarantee that removing the cataract would improve my vision. Why was that?

There are many other conditions that can occur in the eye alongside cataract. The most common of these is ageing change at the back of the eye (macula degeneration). Other causes may be glaucoma or blockage of one of the blood vessels in the eye. In these situations your doctor may be cautious about promising too much improvement in vision following surgery. In these situations it can be difficult to predict if the vision will improve until after the cataract has been removed.

Will my cataract grow back after the operation?

No, once the cataract has been removed it will not return. Sometimes after a few months or even years the capsule that the intraocular lens sits in becomes thickened. This may result in reduced vision again. It is a simple matter to treat this with laser. This splits the thickened capsule and usually returns the vision to what it was before the thickening occurred. This is called a YAG laser capsulotomy and only takes a few minutes. A numbing drop is put into the eye before the procedure and then a contact lens placed temporarily on the front of the eye. It is not uncomfortable.