Wednesday, June 20, 2012

The sun is the best optometrist

The longest day of the year is a great time to remind parents - if you want to reduce the likelihood of nearsightedness in your child, outdoor time is ideal. We wrote about this last year in the New York Times. The tendency toward myopia is genetic, but actually becoming nearsighted depends on environmental factors. Turns out, it's not near work, such as reading at close distances. So...if he wants to read, let him do it outside!


John Kim said...

Are you aware of any evidence that the right type of artificial indoor lighting might help? Very bright and/or "full spectrum" lighting? Thanks.

Sam Wang said...

I'm not sure that the naturalness of it matters that much, except that one would have to be able to tolerate it.

It's not known which pathway the signal goes over. Naively I would expect it to go over either the pathway for color vision or the one that sets the circadian rhythm. In both cases, there are light-sensing proteins with pretty broad sensitivity.

The challenge with indoor lighting is getting enough of it. You'd be amazed at how much the difference is between outdoor and indoor light levels. Think how hard it is to see into a house on a sunny day, and how easy it is to see out.

John Kim said...

Thanks. It seems you're right about the eye's sensitivity to a broad spectrum of light. I found a conference presentation on an experiment that uses fluorescent lights:

Siegwart, J.T., A.H. Ward, T.T. Norton, and others. Moderately Elevated Fluorescent Light Levels Slow Form Deprivation and Minus Lens-Induced Myopia Development in Tree Shrews. Association for Research in Vision and Ophthalmology Annual Meeting 2012.

And I see your point about how much brighter it is outdoor than indoor. A huge difference in lux.