Can contact lenses cause eyesight to deteriorate?

The question as to whether wearing contact lenses make your eyesight worse is common and understandable. However, the reassuring answer is that contact lenses do not have a detrimental effect on your vision.

It is easy to avoid restricting the oxygen supply to your eyes by following simple advice.

Contact lenses are often worn by children and young adults who have been diagnosed at their eye examinations as myopic, or short-sighted. After being prescribed with contact lenses they subsequently attend routine examinations only to discover that their short-sightedness appears to have worsened, leading to the natural assumption that the contact lenses are responsible.

However, myopia often becomes progressively worse during childhood and adolescence and even into adulthood. This affects patients who wear contact lenses and those who do not so there is no link between deteriorating eyesight and the wearing of contact lenses.

Is there scientific proof that contact lenses cause short-sightedness to worsen?

Whether a link exists between the wearing of contact lenses and worsening vision has been the subject of numerous scientific studies.

In one major study - the Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) - researchers investigated myopic progression, sometimes referred to as 'myopic creep', to try to establish whether contact lenses contributed to children's increased short-sightedness.

The study focused on a group of 484 children between the ages of 8 and 17 who had been clinically diagnosed to be suffering from myopia (between -1.00 and -6.00 Diopter) who had not regularly worn contact lenses.

The study - which lasted for a three year period - divided the participants into two groups. One half was given glasses to wear for the duration of the research project while the other children were given soft contact lenses.

At the conclusion of the investigation the myopic creep was measured in each participant and it was determined that there was no significant difference in the progression of the short-sightedness between those children who wore contact lenses and those who wore glasses.

Can contact lenses help to reduce the rate of myopic progression?

While it is scientifically accepted that contact lenses will not cause myopia to worsen, another pertinent question is whether they can reduce the rate of myopic progression or even reverse it altogether.

The question has been the focus of much scrutiny, debate and controversy for a number of years and recently the US National Eye Institute undertook a detailed research project entitled 'The Contact Lens and Myopia Progression (CLAMP) Study' in an effort to establish the truth in the matter.

148 children in the age range 8 to 11 who had short-sightedness were asked to wear prescribed contact lenses. The 116 who were able to adapt to wearing them were given either soft contact lenses or gas permeable lenses (rigid plastic lenses that allow for the transmission of oxygen to the eye). Like the ACHIEVE study, CLAMP lasted for a three year period.

The researchers concluded that the children who wore the gas permeable lenses did experience a slowdown in their myopic progression although the rate was too small to be of significance in terms of choosing these types of lenses above the soft lens equivalents.

There was also no certainty that the decline in rate of myopic progression was permanent.

Should I be concerned about using contact lenses to correct short-sightedness?

In conclusion, if you are considering purchasing contact lenses to correct short-sighted vision, the scientific evidence available does not support assertions that lenses either increase or decrease the rate of myopic progression. Short-sightedness is a natural condition which progresses with time and may eventually stabilise. Contact lenses will, in the interim, provide you with an effective and convenient way to enjoy sharper eyesight, enabling you to go about your daily life more comfortably.