By Dr. Danny VanDan
In an age of easy access to glasses, contact lenses, LASIK surgery, and other forms of vision correction, having bad eyesight is but a mild inconvenience. However, aside from a slight dip in quality of life, poor eyesight can potentially lead to permanent vision loss.
How bad is bad?
Myopia, or nearsightedness, means the eye is too long, front to back. Moderate cases of myopia do not generally cause problems. High myopia, on the other hand, is defined by the World Health Organization as the prescription being equal to or less than -5.00 diopters in either eye.1 If the eye becomes that dangerously long, it increases the risk of conditions that threaten vision including myopic degeneration, cataracts, glaucoma, staphylomas, retinal thinning, and retinal detachments.
Who does it affect?
In the U.S., the National Eye Institute predicts that 12% of Americans will be affected by myopia by 2020. A recent study in Australia found 23% had myopia. But in East Asia, rates have been recorded as high as 90%, starting in Singapore, Hong Kong, Taiwan and spreading to the big cities in China.2 Furthermore, high myopia affects up to 2% of Americans and upwards of 16% in Asian populations.3 The prevalence of high myopia is predicted to increase to 24% in over 120 countries and in high-income Asia-Pacific countries by 2050. It has reached epidemic proportions and is quickly becoming a worldwide public concern.1
So why are so many Asians affected?
There are two main factors that cause the eye to lengthen: environmental and genetic. Previous research has uncovered the environmental factors as time spent in education and time spent outdoors.2
It has been known that extended eye usage at a close distance stimulates eye length growth. With the increase of schoolwork, tablets, smartphones, computers, and conceivable pressure from parents, Asian children and teenagers currently are at a huge risk for high myopia.
Now, we are learning that spending time indoors can also contribute to this increased prevalence. New studies are showing that sun exposure can reduce eye length growth. Unfortunately, technological advancements, video games, and modern culture are further keeping more children and adults indoors.
But why Asians?
The lack of sunlight and extra near work can be said for any number of ethnicities. So why are Asians predisposed to that genetic factor? An Illinois College of Optometry professor had an interesting theory: Ancient Chinese Civil Wars.
Ancient China went through numerous civil wars, rebellions, and uprisings to overthrow emperors – wars that lasted for centuries.4
Some notable wars5
|War||Year||Estimate # of Casualties|
|Qing Dynasty Conquest of Ming Dynasty||1618-1683||25 million|
|Taiping Rebellion||1850-1864||20 million|
|An Lushan Rebellion||755-763||13 million|
|The Dungan Revolt||1862-1877||10 million|
|Republic of China / Communist Party Civil War||1927-1950||7.5 million|
The Chinese men sent to wars were recruited for their tall, strong, physical characteristics and normal eyesight. They would be selected out of the population and would die by the tens of millions. Those considered feeble with short stature and ‘bad eyes’ would not be soldiers. These men would pass on their small physiques and poor vision into the gene pool, while the population gradually bred out bad eyes and large physiques. This theory is based on slave breeding, where slave owners would breed the biggest, strongest slaves to create even bigger, stronger slaves. In a brief period in history, it has greatly impacted the African-American population today. Imagine this occurring for centuries, much longer ago, in a larger scale, but with the opposite outcome in today’s Asian population.
Myopia is increasing at an alarming rate, especially in the Asian population. Moreover, high myopia is threatening our eyes’ health and must be addressed by our political leaders. There are environmental, genetic, and historical factors that have caused this rapid growth. Fortunately, when detected early in life, there are treatments to keep myopia from progressing to its severe counterpart. Contact your local optometrist for annual eye examinations and inquire about myopia control options.