Spending too much time indoors may lead to myopia due to the dimness of indoor lighting
Must read: Sandra Aamodt and my friend Sam Wang explain the latest thinking on the reason for the spread of myopia in developed societies, in the New York Times:
Our genes were originally selected to succeed in a very different world from the one we live in today. Humans' brains and eyes originated long ago, when we spent most of our waking hours in the sun. The process of development takes advantage of such reliable features of the environment, which then may become necessary for normal growth.
Researchers suspect that bright outdoor light helps children's developing eyes maintain the correct distance between the lens and the retina -- which keeps vision in focus. Dim indoor lighting doesn't seem to provide the same kind of feedback. As a result, when children spend too many hours inside, their eyes fail to grow correctly and the distance between the lens and retina becomes too long, causing far-away objects to look blurry.
So I'm happy to correct my earlier post, "Warning: This May Be Hazardous to Your Vision." The problem is the light source, not the reading material. Blame Edison, not Gutenberg. But the recent research raises another question. What display technology is best for outdoor as well as indoor reading? A Zdnet test with an adult subject concludes that for use in natural sunlight, e-ink (e.g. Kindle 2) beats LED-backlit LCD (e.g. iPad 2) hands down. (The Nook color also has an LED display.) What about newer technology like OLED, AMOLED, color e-ink? I've found no answers so far, but since child-friendly displays will also be more comfortable for adult use, findings on vision and sunlight may be a key to the future direction of readers.
Image: REUTERS/Oswaldo Rivas.