By Dr. Jessica Xu
Myopia, commonly known as nearsightedness, has become a global epidemic, especially among children and teens. In the United States and Europe, incidents of myopia among young adults have reached 50% in 2015, doubled the rate sixty years ago. In some Asia countries, the situation is much worse. In China, prevalence of myopia among young adults in cities is 90%, surging from 10-20% sixty years ago.
Myopia is caused by different factors. About 3% or less of the population are born with pathological myopia. A small percentage of the population suffer from diabetic related myopia. The vast majority cases of myopia nowadays are visual stress-induced myopia, also known as simple myopia or school myopia.
Many people experience higher visual stress when doing intensive near-work at digital screens, a health problem called Computer Vision Syndrome. With prevalence of digital devices, school myopia has surged among children and young adults in recent decades.
School myopia is preventable. Good visual hygiene include reading at a good distance, taking frequent breaks while reading and minimizing screen time. It is critical for school children to have good visual hygiene because human eyes are not fully developed until generally twenty years of age.
There has been a long debate whether school myopia is reversible or not. Human eyes are adaptive. When under near-distance stress, the eye axis elongates temporarily. If under near-distance stress constantly, the axial growth becomes “permanent”, resulting in an elongated or myopic eye. A myopic eye is approximately one millimeter longer axially than a normal eye per three minus diopter. In opposite, when under far-distance pressure, the eye axis shortens temporarily. In theory, if under far-distance stress constantly, the axis shall shorten “permanently” and the eye shall become less myopic.
Indeed some myopes regain their normal vision naturally. The joy of seeing the world clearly again without glasses is unbelievable. However, it is difficult to change one’s lifestyle and habits. The vast majority of myopes keep the same lifestyle so they remain myopic or get worse. Natural vision improvement is possible, but requires determination. Similar to losing weight, persistence is the key in reversing school myopia naturally and sustaining the improvement.
In theory, it would be easier for children to reverse school myopia because their eyes are still in development. In reality, it is much more difficult. Part of the problem is that children tend to read at a shorter distance, forget to take breaks while reading, and pay little attention to good visual hygiene. It is no surprise that school myopia has been known as a childhood disease and the vast majority, once becoming myopic as a child, only getting worse until reaching adulthood.
The bigger problem is that schools today demand longer screen time while provide shorter and fewer outdoor recesses. Given the prevalence of technology in our daily life and the hype of educational technology, the trend is so difficult to reverse that a recent study predicted that, by 2050, half of the world population will become nearsighted if current trend continues.
The good news is that using educational technology in PUSD is optional. Parents can choose the more eye-friendly paper-based option in schools for their children, at least to prevent kids’ vision from deteriorating at a young age. Also it is always helpful to encourage kids to practice good visual hygiene.
Our children’s eyes are precious. Let’s take good care of them.
About the author: Dr. Jessica Xu is mother of two PUSD students. Active in the community, she serves on numerous boards including PUSD Parents Group and Rancho Penasquitos Town Council. Professionally, Dr. Xu is a consultant focusing on biotech and pharmaceutical industry.