What are cataracts?
The lens of the eye is situated just behind the iris, and is moved by muscles on either side to allow for clear vision in different light conditions. If the lens becomes cloudy or hazy, the condition is called a cataract. A cataract can vary from some mild cloudiness of the lens to a situation where there is no transparency whatsoever.
The sad fact of the matter is that, although cataracts are highly treatable with very effective surgery, they still remain the most common cause of blindness worldwide.
In Ireland, cataract operations are among the most common surgical procedures carried out at the major hospitals.
How do cataracts develop?
The major reason for cataract development is advancing age. With the ageing process, the lens of the eye becomes less clear. This can ultimately lead to the development of a cataract and a resulting reduction in vision.
While all older people are at risk from cataracts, there is some medical evidence to suggest that there is a slightly higher risk among the following groups:
How are cataracts diagnosed?
The optician will carry out a detailed eye examination, checking the level of vision and ensuring that the most suitable spectacles are being worn. During this examination the pupil of the eye will be dilated and the lens will be examined under magnification.
The optician will also want to know details about the lifestyle of his patient and how much their reduced vision is affecting their daily life and activities.
What are the symptoms?
There are three distinct types of cataracts, but they are not exclusive and all of them may be present in one eye at the same time. They are:
Cortical cataract: This may give rise to double vision and can cause the person to see haloes around bright lights.
Posterior subcapsular lens cataract: This can cause reduction in vision to such an extent that it is difficult to read, and there may be great sensitivity to bright lights and glare.
Nuclear cataract: This causes a gradual reduction in vision, and one of the first indications of the condition may be the fact that reading glasses have to be changed very frequently, maybe even every few weeks.
What is the treatment?
Once a cataract has formed on the lens, no drops or tablets will improve vision or reduce the cataract. The only effective method of removing vision is to have the cataract removed surgically.
What does the surgery involve?
The most common type of cataract operation is called Phacoemulsification. A small hole is made into the eye and the lens is broken up using ultrasound and removed through this hole. A plastic artificial lens is then put into the eye, and this is inserted into the original lens capsule which previously held the patient's own lens in place.
No stitches are required and, provided there are no complications, the patient will leave hospital after a day or two.
In a small minority of cases, extracapsular surgery is used to remove a cataract. This involves making a large incision in the eye, through which the lens is removed. A plastic lens is then inserted before the wound is closed using stitches. A longer hospital stay is required than with conventional cataract surgery, and the risk of post-operative infection is higher due to the eye wound.
Are there any complications of surgery?
The operation to remove cataracts is one of the most successful surgical procedures in Ireland today, with a very high level of patient satisfaction. However, like all surgical procedures there are small risks. These include a build-up of pressure behind the eye; infection; haemorrhage or retinal damage which may result in a reduction in vision or even complete loss of vision in the eye which has been operated on.
Having said that, the benefits of cataract surgery far outweigh the risks, and it is estimated that severe problems following surgery only occur in about one in every 2,000 patients.
What is the recovery time after surgery?
Patients are advised not to go swimming for the first six weeks after surgery because of the increased risk of infection. Heavy lifting, bending and vigorous exercise are not recommended in the first month or, in the case of extracapsular surgery, for the first two months.
Many patients find it very difficult to read after cataract surgery. The reason for this is because there is no focusing power in their new plastic lens. This problem is usually corrected by the wearing of good reading glasses, which will be prescribed about four to five weeks after the operation.