“Can you still read the letters?”
“Yeah,” I replied from behind the phoropter. The optometrist toggled the lenses over and over, until finally the letters blurred. I tried to look around her as she scribbled something on a sheet of paper.
“You have mild myopia.” Seeing my surprise, she added, “Don’t worry. This is very common; you probably just use your computer too much. Your eyes focus on near things well – too well.”
To say that myopia is “common” would be an understatement. An estimated 1.45 billion people worldwide have myopia, or nearsightedness, and this number includes 40-50% of young people in US. In parts of East Asia such as China, Japan, and Singapore, 80% or more high schoolers are nearsighted, and in Seoul, 96.5% of college students have myopia.
Myopia is a condition where the eyeball is slightly longer than normal, so light focuses in front of the retina, as opposed to directly onto it. The resulting blurriness in vision can be corrected with contacts, glasses, or surgery. However, high myopia, a much rarer, more severe form of myopia, can result in cataracts, glaucoma, or even blindness.
Genetics are thought to play a large role in myopia. A study by the Danish Institute for Myopia Research examining genome-wide association studies, family and epidemiology studies, and twin studies, found that genetics, along with some influence from lifestyle, is one of the main factors in whether or not you’ll get myopia. However, a study of Inuit people in Alaska found that the rapid increase in myopia could not be explained by genetic factors. Only 2 out of 131 adults had myopia, but over half of their children and grandchildren were nearsighted. Genetic changes occur much more slowly, and thus can’t explain this puzzling rise. Another study by Berkeley’s Myopia Control Clinic found that the 20 or so genes associated with nearsightedness could explain only about 15 percent of the rise of the “epidemic” of myopia.
Well, if genetics can’t explain the whole problem, what lifestyle differences are to blame? Another commonly held cause of myopia is the increasing focus on intensive education and new technological advances such as laptops. Whether it’s spending too much time peering at a bright computer screen in a dark room,or poring over a textbook, sustained “near work” that forces your eyes to focus on something very close to you increases your chances of getting myopia. Many researchers attribute the higher rates of myopia in Asian countries to the larger emphasis on schoolwork and longer hours spent studying. However, other sources disagree. One study couldn’t find a direct correlation between hours spent texting on a smartphone, watching a computer, or reading a book, and nearsightedness. Instead, these recent studies agree that the primary culprit is lack of exposure to sunlight. Children spending time engaged in indoor physical activities still had much higher rates of myopia than children exercising outside. Light causes dopamine to be released into the retina, which stops the eye from being elongated. The Australian National University concludes that you need to be exposed to light levels of at least 10,000 lux for three hours a day to be protected against myopia. (A well-lit classroom is usually less than 500 lux.)
But even in addition to going out on sunny days, there are other ways to fix or even reverse the effects of myopia. MyoVision lenses, created by the Vision Cooperative Research Center in Australia, actually slows myopic progression, as opposed to normal glasses, which only correct your vision while you’re wearing them. The MyoVision glasses work by bringing the peripheral image forward, while putting the central vision on the retina. Even though it is a relatively new product, studies so far have concluded that the lenses slow or even reverse the onset of myopia.
Another option is to use corrective contact lenses. Orthokeratology uses rigid contact lenses to reverse the myopic elongation of your eyes. I wear corrective contacts at night and have 20/20 vision in the day, but if I don’t wear them for a few days in a row things start getting blurry. However, there are two downsides of ortho-k lenses. First, all contact lenses carry the risk of infection – but sleeping in them raises this risk, especially if you don’t clean the lenses properly. There have been reports of younger children getting infections from wearing these lenses improperly. Second, the ortho-k program is very expensive, ranging from $1,000 to $4,000. And if you accidentally drop a contact down the drain, that’s another $300 (I know this from experience).
Thus, the easiest and fastest solution if you’re noticing that distant objects seem blurry is to expose yourself to more bright sunlight. This is especially relevant to our student body. Around 60% of CPS has some degree of myopia, according to a survey I sent out, (which had over 140 responses). In conclusion, a combination of genetics, prolonged focus on near things, and time indoors causes myopia – but regardless of whether or not sunlight alleviates nearsightedness, it’s good to take a break from studying and go out once in awhile.