Refractive surgery is carried out on the eye to change its focus.
It is usually performed to bring the focus into a natural zone where no glasses or contact lenses are required to see clearly. Most refractive surgery is carried out on the cornea using lasers.
Refractive laser surgery has now reached the point where it is possibly safer to have one’s vision corrected by this method than to have it corrected by wearing soft contact lenses.
People with normal vision who do not require any glasses or contacts usually have an eye that is focused either slightly myopic (shortsighted) or slightly hyperopic (longsighted).
Almost no one has a focus of zero.
However anyone who has vision in this zone can see clearly and regards themselves as independent of glasses. This is the normal state for the human eye. Very complex and poorly understood mechanisms act during the growth of the eye to bring about this state of sharp focus.
Increasingly in modern life it appears that these complex mechanisms are thrown out of balance and more and more people find that they require a correction in the form of either spectacles or contact lenses to see the distance clearly.
In the young people and up to the age of approximately 45 the human eye is naturally focused for distance and then autofocuses for intermediate and near.
This state is referred to as emmetropia.
Ametropia is the state where the eye is not in focus and requires an optical correction to see clearly. Ametropia is on the increase and in certain parts of the world such as the Far East there is what is regarded as an epidemic of myopia,
up to 85% of young people requiring a myopic correction to see clearly.
Little is known as to why this is occurring but emerging evidence seems to indicate the amount of time spent outdoors as a very young child can protect against the development of myopia. It is also possible that there are genetic factors involved so that if your parents were hyperopic or myopic your chances being so are also increased.
Fortunately, concurrently with this worldwide increase in ametropia,
laser technology has undergone enormous progress and now a huge percentage of ametropes can have
The lasers do this by reshaping the contour of the corneal surface so that it changes the focusing power. Scientifically derived nomograms are employed so that just the right amount of laser power is applied to bring that particular eye back to normal focus. And in the last few years enormous strides have been made in increasing the safety and accuracy of these procedures.