What is a cataract?
A cataract is clouding of the lens in your eye. This is usually due to old age but can also occur due to trauma, diabetes, or due to medications.
Cataract surgery is done when the lens in your eye has become cloudy making it difficult for you to see well enough to carry out your usual daily activities. If the cataract is not removed, your vision may stay the same, but it will probably gradually get worse. Waiting for a longer period of time may make the operation more difficult. If you are considering surgery, please let the doctor know if you are taking the following medications: Flomax (Tamsulosin), Doxazosin, Asprin, or any blood thinning drugs like Warfarin, Plavix or Ticlid (Dipyradimole). These medications may need to be stopped before surgery.
You can listen to Dr Fong talking about cataract surgery.
The purpose of the operation is to replace the cataract with a plastic lens (implant) inside your eye. This usually done under local anesthesia. With a local anaesthetic you will be awake during the operation. You will not be able to see what is happening, but you will be aware of a bright light. Just before the operation, you will be given eye drops to enlarge the pupil. After this, you will be given an anaesthetic to numb the eye. This may consist simply of eye drops or injecting local anaesthetic solution into the tissue surrounding the eye. During the operation you will be asked to keep your head still, and lie as flat as possible. The operation normally takes 15 minutes, but may take up to 45 minutes. Most cataracts are removed by a technique called phacoemulsification, in which the surgeon makes a very small cut in the eye, softens the lens with sound waves and removes the cataract through a small tube. The back layer of the lens is left behind. An artificial intraocular lens (IOL) is then inserted to replace the cataract. At the end of the operation, a shield is put over your eye to protect it.
After the operation
If you have discomfort, you can take a pain reliever such as paracetamol every 4-6 hours. It is normal to feel itching, sticky eyelids and mild discomfort for a while after cataract surgery. Some fluid discharge is common. After a few days even mild discomfort should disappear. In most cases, healing will take about two to six weeks, after which new glasses can be prescribed by your optician. You will be given eye drops to reduce inflammation. The hospital staff will explain how and when to use them. Please don’t rub your eye. You will have to put a clear plastic shield over your eye while you are sleeping for 1 week after the operation.
Certain symptoms could mean that you need prompt treatment, including: excessive pain, loss of vision and increasing redness of the eye. Should you develop any problems after surgery, please seek urgent medical attention.
The vast majority of patients have improved eyesight following cataract surgery
After the operation you may read or watch TV almost straight away, but your vision may be blurred. The healing eye needs time to adjust so that it can focus properly with the other eye, especially if the other eye has a cataract. Please note that if you have another condition such as diabetes, glaucoma or AMD, your quality of vision may still be limited even after successful surgery.
Benefits and risks of cataract surgery
The most obvious benefits are greater clarity of vision and improved colour vision. Because lens implants are selected to compensate for existing focusing problems, most people find that their eyesight improves considerably after surgery but will need to replace their glasses. Reading glasses are usually needed after cataract surgery. However, you should be aware that there is a small risk of complications, either during or after the operation.
What type of intraocular lens should you have in your eye?
The most common type of IOL used is a monofocal lens that allows you to see far without glasses. The main problem is that you will need to wear reading glasses to see small print. Another type of IOL available is the multifocal lens which allows you to see far and near without glasses. The main side effect of this type of lens is that you will see bright rings (Haloes) in your vision and get glare when you drive a car at night. This can take up to 3 months to get used to. Multifocal IOLs are also more expensive. You will need to discuss with your eye doctor about the best IOL for your cataract surgery.
Possible complications during the operation
- Tearing of the back part of the lens capsule with disturbance of the gel inside the eyes that may sometimes result in reduced vision.
- Loss of all or part of the cataract into the back of the eye requiring a further operation which may require a general anaesthetic.
- Bleeding inside the eye.
Possible complications after the operation
- Bruising of the eye or eyelids.
- High pressure inside the eye.
- Clouding of the cornea.
- Incorrect strength or dislocation of the implant.
- Swelling of the retina – macular oedema.
- Detached retina which can lead to loss of sight. This is rare.
- Infection in the eye (endophthalmitis) which can lead to loss of sight or even loss of the eye. This is very rare.
- Allergy to the medication used.
Complications are rare and in most cases can be treated effectively. In a small proportion of cases, further surgery may be needed. Very rarely some complications can result in blindness. One of the long-term effects following cataract operation is called ‘posterior capsular opacification’. It may come on gradually after months or years. When this happens, the back part of the lens capsule, which was left in the eye to support the implant, becomes cloudy. This prevents light from reaching the retina. To treat this, the eye specialist uses a laser beam to make a small opening in the cloudy membrane in order to improve the eyesight. This is a painless outpatient procedure which normally takes only a few minutes.
Cataract surgery is now very effective and safe. It is done as a day care procedure and most patients are very satisfied.