Blurry Vision

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Like some thirty per cent of North Americans, I suffer from myopia or near sightedness, where distant objects are blurry.  The problem is that my eyeball is elongated, so that light focuses in front of the retina rather than directly on it.

Now scientists have confirmed the genetic basis of myopia.  Using non-invasive techniques researchers have measured the size of the eyeballs of two hundred and eighty sets of fraternal adult twins, and two hundred and twenty six sets of identical twins.  By analyzing the difference in the eye sizes, researchers found that genes accounted for eighty nine per cent of near sightedness and far sightedness.

Researchers also scanned the entire genome of the fraternal twins and found four sections linked to eye problems.  The most strongly linked segment contains 44 genes, including one which is fundamental to eye growth in nearly all the species that scientists have examined.

Now scientists are debating to what extent environment and lifestyle affects eyesight as well as genetics.  Some studies have shown that an increased literacy rate in a population is usually followed by a significant rise in the rate of myopia.  To what extent children who inherit a genetic propensity to myopia trigger it by reading is still an open question.

So next time things look blurry, be thankful that external lenses can quickly clear up the problem.