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Nearsightedness – protective effect of the sun
Posted on January 13, 2014 | by Dr. Jeff Goodhew Updated: January 13, 2014
Nearsightedness or myopia occurs when objects in the distance are difficult to see. We often see children in our office for eye exams who are struggling to see the board at school. Nearsightedness or myopia occurs when the eye has grown too long from from to back.
The normal eye is to top image. The lower image shows that distance viewed objects are focused in front of the retina leaving them blurry and out of focus.
The focal point typically moves in front of the retina when the eye grows too long from front to back. It only takes .25mm to 0.5mm of extra length for a child to then require glasses for distance.
Parents will often ask us what caused the myopia or nearsightedness. The most common thought is that prolonged use of various devices such as computers, video games and handhelds are the culprits. There is however no evidence in the literature to back that up.
A joint study by the University of Sydney (Australia) and The University of Singapore discovered that time spent outdoors reduced significantly the prevalence of nearsightedness. Ethnicity was removed as a factor because the study group were 6 and 7- year old children of Chinese ethnicity living in Sydney and Singapore.
The study showed that the prevalence of this condition contrasted sharply: 3.3% among those living in Sydney versus 29.1% for those in Singapore.28 A comparison of the children’s lifestyles further revealed that the Sydney group engaged in just as much, if not more, near work than their Singapore counterparts. The biggest difference was the time spent outdoors. The children living in Sydney spent on average 14 hours per week outside versus 3 hours for those living in Singapore.
Below is a public education campaign that the government of Singapore has designed to help reduce the prevalence of Myopia.
More studies need to be done but the protective effect of natural light in reducing the prevalence of nearsightedness seems to be a exciting new discovery.