It is common in developed countries that Babies and young children sleep with an accompanying light, when not with the main light. Cases of myopia are also increasingly common in these countries. Is there any relationship between these facts? Having the light on at night, which can help calm the child, could have negative consequences for his health.
A study published years ago in the journal Nature, reviewed as "Keep your babies in the dark" established a relationship between sleeping regularly with the light on between birth and two years of age and an increase in myopia.
From a survey of the parents of 479 children attending their pediatric ophthalmology clinic as outpatients, Dr. Richard A. Stone and his colleagues found a strong relationship between myopia and exposure to light at night in these Babies and children
The research, conducted by the Medical Center of the University of Pennsylvania and the Children's Hospital of Philadelphia, indicated that:
- 10% of children between 2 and 16 who had slept in the dark until they were two years old were nearsighted at the time of the study.
- 34% of the children who had slept the first two years of life in the nightlight of a dim pilot were nearsighted.
- 55% of children who had slept with a lamp or a lit bulb contracted myopia in adulthood, five times more than among children who had slept in the dark during their first years of life.
The hypothesis to explain these figures would be that the eye develops especially during the first years of life, and therefore, is more vulnerable to light, so there would be no relationship between sleeping with light and myopia after the age of two years and the figures decrease as the intensity of the nightlight decreases.
The researchers admit that the search for a correlation between night lighting and subsequent myopia does not mean that a direct cause has been found, and that other factors have not been ruled out.
For example, children who sleep in brightly lit rooms may become nearsighted because their parents are (the propensity for myopia of children of myopic parents is high) and they prefer to leave the lights on so they can see where they are going and not to have an accident.
But as they stated in their study, it is clear that the absence of darkness in nighttime sleep can be an important risk factor for the future development of a myopia picture.
Could this be the explanation that in the last century myopia cases have increased so much in the most developed populations? There are data that indicate that, especially among the Asian population, myopia exceeds 70% (however, only 1% of the children in the study were of Asian origin).
Leave light or not while the baby sleeps?
Reference is frequently made to this study (dating from 1999) to advise parents not to keep lights on when the baby sleeps.
In fact, the same researchers recommended this action as a precaution, at least until there were more studies that corroborated the relationship, but the truth is that years have passed and we have no record that the subject has been studied again.
Experts advise that small babies do not sleep completely in the dark during the day so as not to alter their circadian rhythm that is being formed, but here we are talking about sleeping at night.
I suppose that the main reason for us to leave an accompanying light is the comfort when getting up at night to breastfeed the baby or change the diaper, to calm him ... without having to turn on the main light, very annoying at midnight.
But it is also true that we finally saw that the light was not necessary (my two daughters slept in our room the first few months) until we had to turn it on to see what was happening to the baby. To fall asleep, they did have dim light, but then we turned it off.
That is, the girls (and we) slept without a light, but we had a pilot light on hand when needed. A soft light, little annoying, and valid enough to move safely, accommodate to breastfeed or change the diaper ...
Now they both sleep without light in their room, and when they call us or need to see them we turn on the hall light, indirectly, which does not bother them.
In short, I think the main thing is that babies and children are calm at bedtime and rest as well as possible, but I don't think that depends on having or not turning on a light at night (and less all night) .
Yes effectively lights at night increase the risk of myopia in children, let us think that the best thing is that the little ones have us close, that they feel that we are there and we go when they need us, that is the greatest light that we can give them, and it also does not carry that probable risk of myopia.
