Researchers in the US have challenged the long-established notion that near work or sitting too close to a television can bring on myopia.
A 20-year study of 4,500 children aged 6-11 by teams at Ohio State University assessed 13 risk factors for nearsightedness to determine the strongest single predictor or set of predictors that could identify those children most likely to develop myopia. These included physical measures and tests of the eyes as well as reports from parents about their children’s activities.
The study, published in JAMA Ophthamology, confirmed that eight of the 13 expected risk factors increased the likelihood that children would become myopic. One important factor was having two nearsighted parents, but researchers said the most surprising exception was near work.
Karla Zadnik, professor and dean of the College of Optometry at The Ohio State University and lead author, said: ‘Near work has been thought to be a cause of myopia, or at least a risk factor, for more than 100 years. Some of the studies that led to that conclusion are hard to refute. In this large dataset from an ethnically representative sample of children, we found no association.’
Researchers also found that measuring a child’s refractive error at the age of six could help predict whether they would develop myopia by the age of 13. It was found that children who grew up with normal vision were slightly hyperopic at the age of six, so a refractive measure which showed little or no farsightedness at that age was a good indicator that myopia would develop as they got older.
‘Myopia is an important public health issue, and anything that adds to our understanding of the risk factors for developing this condition in patients from various ethnicities is welcome,’ said College of Optometrists clinical adviser Dr Susan Blakeney