Views: 0 Author: Site Editor Publish Time: 2024-04-25 Origin: Site
There are many reasons that can lead to myopia, and eye fatigue is certainly one of them. However, personally, I believe that the reason for the sudden increase in myopia rate should be the lack of natural light in the human eye. The biggest change in the social environment for the human eye, from the agricultural and industrial era to the current era of the Internet of Things, is lighting. From the past long period of outdoor reflective natural light to the current indoor direct light screen artificial light that enters the eyes.
It takes billions of years for the eyes to adapt to natural light, while artificial light has only emerged in just a few decades. How could the eyes evolve to adapt to artificial light in such a short period of time? Such an unfavorable lighting environment would naturally cause harm to the eyes.
There is increasing evidence in human and animal research on myopia that environmental light exposure is an important factor in regulating eye growth.
Chickens raised under normal day and night light/dark cycles are also affected by light levels in their refractive development. Chickens raised under high light levels (10000 lux) have significantly lower myopia than those raised under low light levels (50 lux) every day.
In addition, a new study by Michael J. Collins et al. from the School of Optometry and Visual Science at Queensland Polytechnic University in Australia was published in October 2015 in the international authoritative basic research journal IOVS. A study was conducted on 101 children aged 10-15 (41 nearsighted and 60 non nearsighted) for a period of 18 months, using a light sensor on the wrist to collect the average daily exposure of each child during these 18 months.
As shown in the above figure, it was found that children without myopia received significantly higher daily light intensity than children with myopia. During these 18 months, the average axial growth of myopic children (red line) was 0.19mm, while non myopic children (blue line) only increased by an average of 0.05mm. Compared with the low exposure group, the average axial growth rate of the moderate and high light groups decreased by 59%. The axial growth rate of myopic children lacking light was significantly faster than that of non myopic children with higher daily average light. Therefore, it can be seen that exposure to higher daily average light can delay axial growth.
The occurrence of myopia is due to the rapid growth of the eye axis, which widens the eyeball and moves the retina backwards, causing the distance between the focus of light and the retina to become farther, resulting in blurred images.
The normal natural light intensity outdoors is between 11080-18176 lux. Even under the shade of trees, the intensity is 5556-7876 lux. Wearing a hat can result in 4112-8156 lux, while wearing sunglasses can result in a light intensity level between 1792-6800 lux. However, the indoor artificial light environment only has a light intensity of 112-156 lux, and people working indoors for long periods of time have no chance to receive high-intensity natural light outdoors, resulting in an increased axial length of the eyes.
Outdoor natural light is a type of full spectrum high-intensity light that promotes dopamine secretion. Dopamine mediates inhibition of eye growth and acts upstream of the choroid, causing a brief increase in choroid thickness. Injecting non-specific dopamine agonists apomorphine and quinolone into the vitreous body resulted in a significant increase in choroidal thickness in myopic eyes.
Changes in choroidal thickness within 3 hours after injection of dopamine agonists into eyes wearing -10D lenses. The thickness of the choroid is negatively correlated with the length of the eye axis. The thicker the choroid, the shorter the eye axis. Choroidal thickening seems to be a signal that slows down the growth of the eye axis. As long as the choroid thickens, the growth of the eye axis will slow down.
When people, due to work or study reasons, do not have free time to go outdoors, allowing their eyes to receive high-intensity natural light stimulation, resulting in a decrease in dopamine secretion, thinning of the choroid, accelerated axial growth, and the occurrence and development of myopia. In addition, insufficient natural light stimulation can also lead to abnormal development of the eyeball and cornea, which can also induce myopia.
Nowadays, myopia has tended to develop at a younger age, and more and more children and adolescents are suffering from myopia at an early age. Adults directly progress to high myopia. Therefore, it is advocated that children should engage in outdoor activities more often, and the focus is not on activities, but on adding natural light stimulation to the eyes to prevent the occurrence and development of myopia. Allowing students time for outdoor activities every day urgently needs to be taken seriously.
