Increasingly, life is becoming a blur for an increasing number of Americans, with a population-based study indicating soaring rates of myopia i. e. difficulty seeing distant objects. The same trend has been observed in many other countries, which has made eye doctors question as to what could be causing a decline in human vision.

There of some of them, who believe increasing close-up work i. e. time spent on the computer, including a decrease in time spent out of doors, to be the reason.

The National Eye Institute, a part of the National Institutes of Health found, rates of both mild to severe myopia or nearsightedness in people aged between 12 to 54, from 25% in 1971-72 increased to 41.6% in 1999-2004.

A childhood condition that continues to worsen until early adulthood, myopia occurs if the eyeball is too long, or if the cornea (the front cover of the eye) is curved too much. This makes it difficult for the eye to focus the light entering the eye correctly, which makes distant objects look blurred.

The survey findings are based on data from 4,436-Americans from 1971 to 1972, including 8,339-Americans from 1999 through 2004. The survey data was from both blacks and whites, with a dramatic increase in the rates of myopia amongst the blacks i. e. from 13% to 33.5%.

While, hereditary greatly influences the risk of developing myopia, environmental factors also contribute to it. Long periods of close-up work, such as, reading can alter the shape of the eye. Close-up work causes the eye to grow longer; while looking away into the distance relaxes it.

Societal trends also play a part, as children today spend far more time in front of computers than on baseball fields tracking balls hit from far.

The current study has been published in the Archives of Ophthalmology.

Although glasses or contact lenses are used to treat myopia, they increase the risk of other eye diseases like glaucoma, retinal detachment and blindness.

‘People think myopia is benign, but it's a major cause of blindness,’ Dr. Friedman said. ‘With longer, thinner eyes, the retina becomes thin and is prone to breaks and tears.’