I have always heard (from parents and the like) that reading in the dark is bad for your eyes. Is there any truth to this or is it just an urban myth?
Don’t quote me on this (it may very well be an urban legend), but I heard/read that a doctor friend of a lamp maker was once quoted saying it to boost his pal’s sales.
Just been to get my eyes tested last month (20-20 in both eyes, btw). The eye quack - with lots of letters after his name and who was recommended by a very important person - told me it’s a UL. I told him I was finding it a bit harder to read in dark than in the past. He said “get a better light” or just carry on. It won’t do any damage.
I guess your eyes straining to see dim characters for extended periods of time can’t be good for your eyes, but I’ve heard it’s a myth as well.
Semi-myth, really. While no true damage can occur, reading in dim light usually leads to holding the page close to the face, which can lead to a condition called accommodative spasm – the eye muscles won’t return to their normal position, and distance vision is impaired. Unlike true myopia, however, accommodative spasm can be reversed easily by stopping the causative behavior, with a little vision training thrown in.
A not-so-well-known fact: Your eyes require more light as you age.
I other words, what a 40 year old parent perceives as dim light might be more than adequate for a 10 year old.
Any qualified optician will tell you that you can no more harm your eyes by reading in the dark than you can harm a camera by using it in poor light. Some people suggest the ‘harm’ comes from your eyes ‘straining’ to read by poor light, but this just isn’t so. Your eye tries to compensate for low illumination by dilating the pupil to allow as much light as possible to enter. This is not a strain on the circular ‘sphincter’ muscle involved.
I have certainly found this to be the case. But I wonder, is this because the lenses are getting slightly opaque or because of age-related stiffening. In other words do I need more light so my pupils will shrink and the narrower aperture increase the depth of focus and allow me to hold it closer or I simply need more light to see by?
I after reading this I wonder if reading by too bright of a light can damage the eyes. Perhaps an adult needs a 100-120W bulb to read but a child might do damage by reading by such a bright light and would do better with a 60-75W bulb?
Eyes themselves are pretty hard to damage. You can injure the eye muscles like any other muscle (which is why your eyes get sore after squinting, as in reading something you can’t quite see). I suspect a professional would say that you should read at a light level that is comfortable to you.
Three reasons this happens, and you hit two of them:
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the lenses become opaque, or at least less clear (wearing sunglasses will help minimize this)
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close focus becomes more difficult with age (presbyopia) and brighter light will, to some degree, compensate for this by increasing the depth of focus
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the retina itself becomes less sensitive to light. In other words, even if the other two were not factors, you’d still need more light at 60 than at 40, and more at 40 than 20
As a child, I remember the amount of light my parents felt comfortable with was frequently uncomfortably bright to me. Now that I’m reaching 40 and they’ve both had cataract surgery (to remove those opaquifying lenses) we can meet on a middle ground.