What is a cataract?
A cataract is when the lens of the eye goes cloudy. The eye is like a camera with a clear front cover ( the cornea ) a lens and a film at the back of the ( the retina). The lens is like a bag with a clear centre of lens fibres. When you are young these fibres are evenly arranged giving a clear lens but as you get the older the regular arrangement of the fibres breaks down and the lens becomes hazy.
A cataract operation is when the old hazy lens is removed and a new plastic lens is inserted inside the bag of the old lens.
The operation takes about 10-15 minutes and is performed using eye drops as anaesthetic. The pupil is dilated so that the surgeon can get access to the lens. The patient walks into the operating theatre and sits down on a dentists type of chair which then lies the patient flat. The face is covered with a plastic drape to keep the patient dry during the operation. A small 2-3mm incision is made at the edge of the cornea and a circular hole is created in the front capsule of the lens. The main part of the cataract or lens nucleus is then broken up with ultrasound so that the 10mm lens can be removed through the 2-3 mm incision. The bag of the lens is then cleaned up before inserting the new lens inside the bag of the old lens.
The new lens is rolled up and then opens inside the eye like a ship in a bottle.
At the end of the operation the small inicision snaps shut and seals without stitches and finally some antibiotic is injected into the eye to reduce the chance of infection.
After the surgery the vision will be very blurred for 24-48 hours until the pupil comes down to normal after being dilated for the operation and can take 4-5 weeks to get to its best. You will be asked to put in steroid drops three times per day for three weeks until you see the surgeon for a check up in the eye clinic. After 5 weeks you can return to see your optician to get some new glasses.
What are the risks?
The overall risk of making the vision worse following cataract surgery is about 1% making it one of the safest operations in medicine. During the surgery it is possible to damage the posterior capsule ( back layer of the bag of the lens ) and disturb the vitreous jelly that fills the back of the eye. Infection can occur in less than 1 in a thousand cases and can be very serious and potentially sight threatening. Inflammation in the retina occurs in 2-5% of patients and is treated with more steroid drops. The main long term complication is posterior capsule opacification which is when the back layer of the bag of the lens goes hazy which causes blurred vision. This occurs in about 20% of patients over 5 years but is easily treated using a laser in the outpatient clinic.
What will I see afterwards when it has settled down?
During a cataract operation the old lens is replaced by a new plastic lens. It is possible to adjust the power of the lens so that glasses are not required for distance vision in most patients even if you have been shortsighted or longsighted all your life.
The measurements that we take before surgery ( Biometry ) give the surgeon the information to choose the power of the lens but it is not an exact science so perfect distance vision cannot be guarenteed.
Will I be able to see to read without glasses?
If you have been shortsighted all your life you may prefer to remain shortsighted so that you can continue to read without glasses and continue to wear distance glasses. Please let your surgeon know if this is your preference.
Most patients will require reading glasses.
Can I have one eye for reading and one for distance?
A few patients who are usually contact lens wearers are used to having the focus set in the distance for one eye and for reading in the other. If this has worked well for you we can re-create this situation so that you do not need reading glasses. In general patients should have tried this with contact lenses before considering this option.