Cataract
is an opacity or haziness in the lens of the eye resulting in
a greater or lesser degree of blurred vision. The lens is that
part of the eye that focuses what we see on to the light-sensitive
retina at the back of the eye. If the lens is not clear, vision
may be impaired. The commonest form of cataract is senile cataract,
resulting from a breakdown of protein within the lens and which
develops as we get older. 65% of people between the ages of
50 and 59 have some degree of cataract as do all people above
the age of 80. How well people who have cataract can see, depends
upon the severity of the opacity and, whether or not, it affects
both eyes. Some people are born with cataracts and various diseases,
such as diabetes, and some eye injuries pre-dispose to cataract
formation. The diminution of vision may be severe but in some
it is hardly noticeable. Some people only become aware of their
cataract whilst driving at night and being confronted by oncoming
headlights. In these circumstances there can be some dazzling
of vision rather like the same headlights reflecting off a misty
windscreen.
There is no effective, proven medical treatment for cataract. A well-placed reading light that provides illumination from above and behind may help the sufferer. The only effective treatment of cataract, if, indeed, treatment is needed, is surgical removal of the lens, usually these days, with its replacement by an intraocular implant. The decision whether to operate will depend upon the amount of disability the patient perceives – the younger the patient the less the tolerance to visual impairment – and the state of the rest of the eye, particularly the retina. It is not true, as is popularly believed, that cataract is a skin that can be peeled off the lens, neither do cataracts have to be “ripe” before surgery is undertaken. |
