Cataract & Surgery
What is a cataract?
A cataract is clouding of the focusing lens in your eye. The lens is situated just behind the pupil, in the middle of the eye. In the perfect eye, the lens is clear. As a cataract develops, the lens becomes cloudy, rather like frosted glass. Light rays cannot pass through the lens and the vision progressively worsens. A cataract is not a skin growing over the eye, as some people may think.
When does a cataract need surgery?
In the early stages of cataract formation, new glasses may improve your vision. Later, as the lens becomes thick and cloudy, glasses will not help. If your vision is poor enough to prevent you doing the things you like to do, you may need cataract surgery.
Benefits of cataract surgery
Following routine cataract surgery your vision will improve and colours will be brighter. However, if you have any other disease affecting your eye, eg. macular degeneration, diabetes or glaucoma, your vision may still be limited even after successful surgery.
You need to have an operation to have a cataract removed. Phacoemulsification is the operation of choice in majority of cases.
Cataract Surgery - Phacoemulsification.
Phacoemulsification is a technique used to perform small incision cataract extraction. Small incision cataract extraction utilises a tiny wound measuring less than 3mm to remove the cataract, the folding lens is then inserted and the wound does not usually require a stitch. The small self-sealing incision allows rapid rehabilitation following the surgery.
Cataract Surgery - Conventional Surgery (Older operation)
A large incision is made in the eye. The delicate capsule in the eye is opened. The lens is removed manually and a plastic lens is inserted. Stitches are used to seal the incision.
Cataract Surgery - The Technique for you
Most patients are suitable for small incision sutureless cataract extraction (phacoemulsification). Some patients with other eye problems are better managed by conventional large incision surgery. The technique used may be decided by the surgeon at the time of surgery or may be changed during the surgery.
Scan measurements of your eye (Biometry) will be performed - data from these measurements is used to calculate the strength of the intraocular lens implant used for your operation. In some cases, corneal topography and other tests may be performed.
If you are having a general anaesthetic, some blood tests may be needed.
Most patients have their surgery performed under local anaesthetic. This is usually done either with anaesthetic drops alone or an injection around the eye, although sometimes other techniques are used. This allows rapid recovery following your operation. You may be able to see shapes and lights and sometimes feel a pulling sensation. Injections around the eye can rarely cause bleeding around the eye or other sight threatening complications eg globe perforation which may result in postponing the operation. If you are having a local anaesthetic, you usually do not need to fast prior to surgery. If you feel any pain during the operation you should inform the surgeon during the operation. He can top up the anaesthetic.
Some patients have a general anaesthetic - this will be decided by the doctor in consultation with you, at the time that you are placed on the waiting list for surgery. General anaesthetic means that you are asleep. If you are having a general anaesthetic, you will need to fast for six hours before your operation. There are exceptions to this if there are any other general health concerns. You will be given instructions regarding fasting prior to the operation.
Cataract Surgery - Preparation
On arrival to the ward you will be seen by the nurses. The nurses will instruct you on exactly what you should do. You will be seen by the doctor before your operation. You can expect to spend almost half a day for your surgery. Your pupils will be dilated one hour prior to surgery.
You will be placed on a specialised operating trolley with a cushion for your head. The skin around your eyes is cleansed and sterile drapes are placed around your head, covering your other eye. A small clip will be placed on your finger which monitors your heart rate. A tube will be placed on your chin which will deliver fresh air to you underneath the sterile drapes.
Cataract Surgery - The Procedure
An operating microscope is used to perform cataract surgery. The operation lasts approximately 10-30 minutes. An incision is made into your eye. The envelope or capsule which contains the lens is then opened and the cataract is removed with a machine using sound waves – phacoemulsification. You may hear the noise of the equipment. The intraocular lens implant is placed in the capsular bag. Occasionally it may be necessary to put a stitch to secure the wound. An injection of antibiotic is given at the end of the operation. This can be slightly uncomfortable. A dressing is then placed on your eye.
Cataract Surgery - After surgery
The surgeon will inform you about the removal of your eye dressing. Eye drops can be started at this time as per the directions of your doctor. Following your cataract operation you will be seen within 2 weeks of your surgery by a doctor. You will need to use eye drops four times a day at least.
The day following your surgery, you should not be in any pain. The eye may be red, it may water and there may be some double vision, but these should improve within a day or two. Your vision will gradually improve over the next few days. If you are worried about your eye, you should contact us.
Will I need glasses after surgery?
Yes. You will need to change your glasses following cataract surgery. This will be after 4-6 weeks if you have had small incision surgery. If stitches have been used, you may need to have the stitches removed before glasses can be prescribed. Following cataract surgery the eye looses the ability to focus. Hence you will need reading glasses for near vision. Some patients may need a small correction for distance vision as well. However, new intraocular lens implants are available which may allow you to read at both near and distance, without glasses. Please discuss this option with your surgeon.
What are the main risks of surgery?
The vast majority of patients are delighted with the results of their cataract surgery. However, there is a small risk of potential complications following cataract surgery. Some problems are very minor and resolve very quickly but some are potentially sight threatening. A few of these complications may need another operation.
|Some complications during the surgery:||Some complications after the surgery:|
|Tearing of the lens capsule alone or combined with disturbance of the gel (vitreous) in the back compartment of your eye||Bruising of the eye or eyelids|
|Loss of part or all of the cataract into the vitreous||High pressure in the eye|
|Bleeding inside the eye||Clouding of the cornea|
|Inability to insert an intraocular lens implant||Leaking wound|
|Incorrect strength or dislocation of the implant|
|Swelling of the retina – macular oedema|
|Infection in the eye – endophthalmitis|
|Allergy to medication|
|Droopy lid (ptosis)|
|Loss of vision or even the eye (extremely rare)|
The long term
Your operated eye should be stable and you would not expect any significant change over time. You will usually be discharged from follow up following your cataract surgery. If you have stitches, these may be removed or become loose with time. You may develop a gritty sensation in your eye, if this occurs you need to be seen for removal of the stitch. This can be done very simply at the slit lamp in the clinic.
Once you have been discharged, you should see your optometrist every year. If you have an early cataract in your other eye, your optometrist can detect if your vision has fallen and may recommend a review to see if cataract surgery is now indicated.
Your optometrist may also detect if you have developed thickening of the posterior capsule. Posterior capsule thickening occurs in approximately 10% of all patients following successful cataract surgery, sometimes many years following surgery. The membrane around the lens, called the posterior capsule, is left in place at the time of surgery. It is used to support the plastic intraocular lens implant. The posterior capsule may thicken causing ‘misting’ of your vision. The thickening of the posterior capsule can be rectified by laser surgery. This laser capsulotomy can be performed painlessly as an out-patient. The laser makes a small hole in the capsule and improves the vision again.