Nearsightedness on the rise in Asia, Chinese Saccades

asian student wears glasses for myopiaChildren are under a great deal of pressure to excel in their studies in Southeast Asia, and a new study in The Lancet shows they may by paying the price by damaging their eyes. Myopia, or nearsightedness, used to have a rate of 20% to 30% on average in Southeast Asia. A recent study put that number at more than 80% in young adults.

School is very competitive, and many students spend most of their time indoors studying and taking classes. They do not receive sufficient amounts of outdoor light to counter-act their indoor eye use.

Myopia Symptoms

The symptom of myopia is blurred medium- and long-distance vision beyond 6-1/2 feet. Near objects can be focused on, but distant objects are fuzzy. It is often caused by the eyeball elongating in youth or childhood. The conventional treatment is eyeglasses that become stronger over time. Some nutritional and lifestyle changes and exercises may also help with myopia.

According to the researchers, just two or three hours of daylight could counterbalance excessive time spent studying. The researchers hypothesized that the brain chemical dopamine could be playing a role. Levels of dopamine in the eye are effected by exposure to light, and sufficient dopamine seems to prevent the eyeball from elongating. Spending 2-3 hours outdoors even on overcast days may help the body produce enough dopamine to prevent nearsightedness.

Sun is brightest at noon, but this is when many children in Southeast Asia take a nap. They miss the best time of day to get the most amount of natural light.

“High” Myopia

More extreme cases of myopia are called “high” myopia. Approximately 10% to 20% of students in Southeast Asia had the condition to this extent. Visual impairment, vision loss, and blindness can result. Education of both optometrists and parents is important so that everyone knows the risks and doesn’t keep blindly increasing the power prescriptions for glasses.

In the past, researchers thought genetics played a large part. However, this research may contradict genetics as the most important factor. Singapore, for example, represents three ethnic groups (Malay, Indian and Chinese backgrounds) that have all seen a sharp increase in nearsightedness/myopia. Additionally, the sharp increase cannot be explained using genetics.

Study: Myopia by Ian G Morgan, Kyoko Ohno-Matsui, Seang-Mei Saw PhD. The Lancet. Volume 379, Issue 9827, Pages 1739 – 1748, 5 May 2012 doi:10.1016/S0140-6736(12)60272-4

Eye Movements Different in China

Do brains and eyes work differently in various parts of the world?

A team of scientists has discovered that the eyes of Chinese and British people move differently.  Recognizing that Chinese people exhibit a specific eye movement that is rare in British people shows that different populations could have different brain mechanisms.  It was thought that a particular eye movement was a mark of brain injuries when the research sample was based on a largely European population.  This study shows that this eye movement was in fact common in 30% of the Chinese people studied.  These findings, published in the journal Experimental Brain Research, will keep physicians from misdiagnosing brain injuries now that it is know that certain eye movements, called saccades, are actually normal in certain populations.

According to Dr. Paul Knox, “There could be a number of explanations for this and further investigation is needed to fully understand why populations differ. It could be that culture – where we grow up, the education, work and social activities we are exposed to – influence these particular biological responses even though our physical make-up is the same…. The other possibility is that there are basic differences in brain structure and function that produce the kind of behavior we identified. Maps of the brain were developed many years ago and were largely based on European populations. This became the blueprint for brain structure, but there could be differences between various populations.”

Source: Medical News Today