Can spending too much time in front of a computer screen cause short-sightedness?
Computer screens have been blamed for short-sightedness, just as reading for too long under the bedclothes was when I was a boy. Actually, you are short-sighted because your eyeball grows too long for your lens, but the growth is slowed down by a brain chemical called dopamine in the retina.
A recent Australian study suggested that exposure to sunlight in childhood stimulates the production of dopamine, so the eyeball stays the right length. But if you don't get enough sunlight, the theory goes, you won't produce enough dopamine. People who spend a lot of time in front of screens are less likely to go outdoors, so it's not the computers themselves that may cause shortsightedness - and there is definitely a genetic component.
Doctor's orders: Kids should get out more!
Dr Michael Mosley in Radio Times, 11-17 Oct. 2014
