14 DAY TRIAL // A baby may be sunshine for the parents, but sunshine for the baby is really harmful. There is a higher risk of myopia later in life. About 25 % of myopia cases seem to be caused by a too great exposure to sunlight in the first weeks of life.
It was already known that over-exposure to sunlight caused myopia in animals. But a new research, the largest of its type, made on about 300,000 young adults, Israeli soldiers aged 16 to 23, revealed that those born in June and July had a 25 % higher chance of experiencing severe myopia than those born in December or January.
"It was because prolonged illumination causes the eyeball to lengthen - causing short-sightedness." said lead research Professor Michael Belkin, of Tel Aviv University.
Thus, more light on the first weeks of life translates into a more lengthened eyeball and worse myopia.
The lengthening of the eyeball is connected to amounts of melatonin, the dark pigment that protects the skin against harmful UV radiation from the sunlight. Infants do not synthesize enough melatonin and this way they are more exposed to sunburn and shifts on eyeball shape.
In the western world, about one third of the population experiences myopia.
First, Belkin had detected a link between birth season and myopia on a research made on chickens. The myopia degree in chickens was controlled through their light exposure in their first weeks.
The investigation made on humans revealed that those born in winter or autumn will have a better long-range sight and are less likely to develop myopia.
Belkin said the results are valid worldwide, even in more northern less sunny areas than Israel.
"The eye in childhood is much clearer than when we are older so it's vital that children start to wear sunglasses from birth onwards," said Belkin.
"At the moment we don't know the precise cause of why light exposure affects sight, but the evidence seems to prove that it is one of the reasons for people becoming shortsighted. It would make sense to put sunglasses on babies born in the summer, or better still keep them out of strong sunlight for the first few weeks of their life." said sight expert Professor Daniel O'Leary, of Anglia Ruskin University in Cambridge.