The cause lies in the process of human growth!
In fact, many of the triggers and causes are hidden in the process of human growth. Let's take a look at the relationship between human growth and eye structure.
The first is the baby's eyesight. Babies' eyesight at birth is about 0.02 to 0.05, and they can only vaguely see objects that are 20 to 30 centimeters away.
By looking at things every day, your baby will gradually develop their eyesight. Although the performance of the eyeball itself is not much different from that of an adult, the function of the cerebrum (visual cortex) that processes information coming from the eyes is underdeveloped, so it is still not possible to perceive things clearly.
Visual acuity is 0.3 at 1 year old. When the baby can sit up, the baby's perspective becomes higher, and the depth, height, three-dimensionality and distance of objects are perceived as visual information.
Visual acuity develops to about 0.5 at the age of 2, but it is not until they grow up that they acquire the same level of visual acuity as adults.
Once the child can stand and walk, the child's perspective becomes even higher. In this way, the same field of vision as an adult will open up. By the age of 6, most children have visual acuity of 1.0, and it is said that their visual acuity is complete around this time. It is said that the binocular vision function to perceive things three-dimensionally is completed at the age of 6 to 8 years old.
In this way, we can see that vision is completed at a much earlier stage than physical development. Therefore, it can be said that myopia begins early.
The percentage of people with low visual acuity (visual acuity of 1.0 or less) is increasing year by year.
A child's visual acuity of 1.5 or 2.0 is not uncommon, is it?
In fact, the eyes of children who have perfected their eyesight are originally very good.
This is because the eye axis (the length from the lens to the retina) of children is slightly shorter than that of adults, and even when looking at a distance, the focus is not properly aligned and is often shifted behind the retina. In short, they are often farsighted. In fact, visual acuity of 1.5 or 2.0 in children is not uncommon. Then, as the child grows, the eye axis begins to elongate, and the eye becomes normal.
What happens if these children habitually study too much at their desks, or become engrossed in video games and stare at screens before they acquire normal adult eyesight?
The eye of a growing child has a high ability to adapt to the environment, so the ciliary body adapts the eyeball itself so that it can see up close without making the lens too thick.
For example, the corneal curve is strengthened to increase the convex lens effect, the eye axis is elongated to make it easier to see near objects, and the structure of the eye itself is changed according to the environment. . Instead of adjusting it with the ciliary muscle, it adapts the shape of its own eyes to the environment to make it easier to see.
As the eye adapts to make it easier to see up close, this time it becomes difficult to see far away. It is a state of pseudomyopia.
Pseudomyopia is said to be cured in the long run just by trying not to look too close. However, if you correct it with glasses or contact lenses immediately, it will not recover well.
If the lens is thickened without restoring the function of the ciliary muscles, the eye will adapt to the condition and become true myopia.
Take measures before vision loss becomes normal.
In addition, if you leave the state of pseudomyopia unattended and continue to stare at nearby objects for a long time every day, the ciliary muscle will become exhausted and will not work, and the thickened lens will not be able to return to its normal state. . When this happens, even if you give your eyes a little rest, it will be very difficult to regain your vision.
It is important to restore vision before vision loss becomes normal.
Children who spend more time playing outdoors are less likely to be nearsighted.
A comparison of 6- and 7-year-old Chinese children living in Sydney, Australia, and Singapore found that although parents had similar prevalence of myopia (at least about 70% of their fathers or mothers were myopic), The rate of myopia among children was found to be more than eight times higher in Singapore (29.1%) than in Sydney (3.3%).
Children in Sydney spent an average of 14 hours a week outside, while children in Singapore spent an average of 3 hours a week.
It doesn't seem to matter what you do outside.
Children who spent two hours a day outdoors were four times less likely to be myopic than those who spent less than one hour a day.
Playing sports indoors does not affect vision development. Children with both myopic parents are less likely to become myopic after outdoor activities than children with non-myopic parents. This suggests that myopia-related genes are also associated with sensitivity to environmental influences.
Interestingly, time spent outdoors had a stronger effect on 6-year-olds compared to 11- to 12-year-olds. It is said that the development of a person's ability to see almost ends at around the age of 6 to 10. For that reason alone, the period between the ages of 3 and 6 is an important period of life for the development of visual acuity. The impact on the environment, including time outdoors during this time of year, is likely to be greater.