Minimising the myopia epidemic
Modifiable risk factors in childhood could help to reduce high myopia.
Caroline Klaver MD
People who develop myopia before the age of 13 have a much higher risk of high, pathological myopia later in life, Caroline Klaver MD, PhD, told delegates at an ESCRS clinical research symposium during the 36th Annual Congress of the ESCRS in Vienna.
“This is significant because the risk of bilateral visual impairment and blindness is strongly correlated with the degree of myopia, particularly as represented by axial length. Nearly 20% of patients in whom myopia begins before age 10 will go on to become highly myopic, said Dr Klaver, Erasmus University Medical Centre, Rotterdam, the Netherlands.
There is a worldwide myopia epidemic, which will have significant consequences for ocular morbidity in the future. It is thus of interest to study the phenomenon to be able to devise plans to minimise its impact. The risk of developing high myopia is multifactorial. Genetic risk is significant.
“Many genes of small effect determine refractive error and myopia, and all cell types in the retina express refractive error genes. But myopia is really all about lifestyle in children, as far as modifiable factors are involved. Those that have both high genetic risk and higher education, or high genetic risk plus high environmental risk, are particularly at risk for pathological myopia,” said Dr Klaver.
Environmental risks include spending too little time pursuing traditional childhood activities, notably playing outdoors. Two hours or more outside per day is protective, she said.
According to the Rotterdam Eye Study, myopes spend more time indoors, have lower vitamin D levels (vitamin D is a proxy for time spent outdoors) and spend more hours on near work. There are significant correlations between a lack of various biomarkers for outdoor exposure and myopia.
What about smartphone use? Is there such a thing as “too much” in terms of development of myopia? There are no good data regarding smartphone use, said Dr Klaver, although studies are currently ongoing.
Dr Klaver encourages paediatric patients to follow the 20-20-2 Rule.
“After 20 minutes of near work, you should take a 20-second ‘accommodation break’ during which you look far ahead into the distance, allowing the accommodation to relax. And, children should spend two hours per day outside.”
Does the use of sunglasses negate the effects of time spent outdoors? There are no real data about that yet, either, she noted.