Contact Lenses

Affordable Contact Lenses

It is necessary to enlighten people about some facts and fallacies regarding contact lenses.

The first contact lens came into existence in 1887. This lens was double-walled and was made of glass. The lens contained between it two walls, a substance called gelatin. At that time, however, there was no way of measuring the anterior curvature of the eye-ball. Hence the lens did not fit well on the eye and had to be discarded.

In 1932, Dr. Joseph Dallos succeeded in measuring the curvature of the eye-ball and prepared a glass contact lens accordingly. This lens, however, happened to be too heavy to be worn comfortably even for a few seconds. In 1943, plastic contact lenses made their appearance.

These lenses were made to fit on whole of the other surface of the eye-ball and were termed sclera contacts lenses. In 1948, cornel contacts lenses came into existence. Such lenses are fitted only on the transparent part of eye i.e. cornea.

Special Effect of Contact Lenses

There are a few eye-defects which are more amendable to contact lenses than to glass. Contact lenses are to great value in correcting high astigmatism (irregular sight), keretoconus (cone-shaped cornea) and high anisometropia with glasses usually results into double vision. This difficulty can be overcome with contact lenses

Certain defects arising out of the use of glasses can be overcome with contact lenses. A person can see clearly only if he sees through the centre of the glass.

Perepheral or paracentral parts of glasses give rise to defects like spherical aberration, chromatic aberration and coma.

Due to this the person has to contend with a limited field of vision. On the other hand, since the contact lenses move with the eyes, one always sees through the centres of the lenses. Hence the question of above-mentioned defects does not arise

It is said that contact lenses help to check the increase of eye-defect and the number (of spectacles) becomes steady. However, innumerable cases have been seen where the eye-defect has continued to increase even after the use of contact lenses. In fact, this point needs further elucidation.

We know that a visual defect has a tendency to grow along with the growth of the body. In many cases, the defect stops getting worse at around 17-18 years of age.

It is difficult to say whether the eye-numbers have stopped increasing as per the natural course or due to the use of contact lenses.

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