Thane found a link on BBC this morning to an article about myopia, nearsightedness. It's been traditionally thought that myopia is inherited as well as exacerbated by excessive reading or other close work - a description that certainly seemed to explain my extreme nearsightedness as a child. This article focused (ha, ha) on another theory: myopia may be impacted by genetics and habits, but the primary cause seems to be too much time spent indoors.
Apparently, the connection should have been made 50 years ago when a study of Inuits in northern Canada revealed that almost none of the older generation had myopia, but 10-25% of the younger generation did - a result that could not be the result of genetics. Subsequent studies from around the world have shown that the biggest impact on myopia may be sunshine.
A specially designed study found that "kids with good eyesight turned out to be no more active than those with specs – ruling out the possibility that exercise and general good health protect the eyes. Instead, glasses prescriptions seemed to hinge, almost exclusively, on the time spent in the sunshine. Bright sunlight can be thousands of times more intense than lighting inside (though your eyes may mask the difference) – and the more sunlight the children enjoyed, the less likely they were to need glasses."
Now, I don't know if there can be a retroactive effect for us adults who are visually challenged, but the study was on my mind when I went out for a walk at high noon today, the first sunny day we've had here in Valdez in at least three weeks. Because of the low angle of ol' Sol and high surrounding mountains, we don't actually get sun at our house this time of year. I haven't ever paid attention to when we lose and regain it (I usually leave and return in the dark most days), but I suspect we're sun deprived for at least a month. Today, however, I only had to walk a mile and a half or so behind my house to bask in its mid-winter weakness for a few minutes.
I remember hearing an interview with the Alaska state epidemiologist on NPR years ago. He said that at no time during the year is the sun in Alaska intense enough to meet our vitamin D needs. He brought up this depressing tidbit in a conversation about a resurgence of rickets in bush Alaska caused by kids drinking too much soda and not enough vitamin D-enriched milk. I'd be curious to know what intensity of sun, or how many hours outside per day in it, would be required to keep our childrens' eyes from developing myopia.
Regardless of the medical benefit, I am a firm believer in the mental benefits of time spent outdoors, especially in sunshine. An hour or so spent moving outdoors provides me with desperately needed time to process life: find possible paths through relationship problems, consider solutions to creative conundrums, even finally find words to express myself after a long drought. As I tromped toward Corbin Creek and the sunshine this afternoon, I realized that my vision is improved in many ways by spending time outdoors. In the words of an old Jimmy Cliff song, "I can see clearly now, the rain is gone. I can see all obstacles in my way." Figuaratively if not literally.
