Is being short sighted genetic?

No one knows for sure exactly what causes short-sightedness but there’s ample evidence that inherited characteristics play a significant role.

As the name implies, short-sighted people can see clearly up close but have difficulty seeing objects that are farther away. Also called myopia, short-sightedness is a refractive error, not an eye disease.

Generally, it occurs because the eyeball grows too long, so light doesn’t focus on the retina but falls 'short' - thus the name. Why this happens to some people and not others is still not fully understood.

Recently, researchers gathered data from more than 250,000 individuals from Europe, Asia and North America to evaluate the influence of genetics on myopia. From this study, they were able to identify 161 genetic factors associated with myopia, most of which were previously unknown.

While each of these myopia-prone genes has only a small influence on the risk of becoming myopic, individuals who carry a large number of them have up to 10 times the risk compared with others who don't have them.

Heredity alone, however, doesn't account fully for the dramatic increase in the prevalence of myopia worldwide in recent decades. According to the Brien Holden Vision Institute at the University of NSW right here in Australia, approximately 30 percent of the global population currently is short-sighted. In some East Asian countries, 80 percent or more of their residents are short-sighted. The Institute also predicts that if current trends continue, more than half the world's population will be short-sighted by 2050.

Environmental factors also appear to play a role in the development of short-sightedness. For example, long hours spent reading or focusing on computer screens, tablets and smartphones is believed to increase the risk of myopia progression among children.

Another contributing factor is believed to be spending less time outdoors. Sunlight stimulates production of the neurotransmitter dopamine, which is a factor in controlling the elongation of the eyes. The theory is that more sun exposure means more dopamine production, leading to less elongation of the eyeballs and a reduced likelihood of developing short-sightedness.

Myopia usually begins during childhood and can worsen year after year until early adulthood, often, children who are becoming short-sighted aren't aware their vision is declining.

To monitor your child's vision, schedule an eye examination at the beginning of each school year with an optometrist near you.

READ RELATED: Is short sightedness common?

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