1.Outdoor Activities At Night

Some parents in the clinic will ask, "Dr. Yang, I force my children to go out for a walk and exercise for nearly an hour after dinner every day, but why can't I control my myopia well?" As we have said before, the core of outdoor activities to prevent myopia is sunlight. Walking out at night is of little use except for the faint sunlight reflected by the moon. Therefore, we must keep in mind that outdoor activities are best during the day!

2.No Effect Of Outdoor Activities On Cloudy Days?

The study found that when the ambient illumination is above 1000lux, myopia prevention and control will be of significant significance. When the ambient brightness is above 3000lux ~ 5000lux, the progress speed of myopia will drop another step. Although the illumination of 1000lux is difficult to achieve indoors, it is easy to achieve outdoors even in cloudy or cloudy days. The illuminance on sunny days can easily exceed 10000 lux. Therefore, although the sunlight illumination on cloudy days will be significantly lower than that on sunny days, it will still have a very good myopia prevention and control effect compared with indoor. Moreover, compared with sunny days, Dr. Yang personally prefers to take her out in cloudy weather. For one thing, the sunlight illumination at this time is relatively weak and not dazzling. Second, the UV content is relatively low and does less harm to the eyes. (from the perspective of myopia prevention and control, ultraviolet light is a good thing. However, ultraviolet light will cause chronic photochemical damage to eye cells, so it is not easy to be exposed to too strong ultraviolet light for a long time.) Third, compared with the hot sun in the sky, the cloudy weather is relatively cool, and the children will spend more time outside.

3.Have To "Exercise" Outdoors For 2 Hours?

In order to prevent myopia, many parents spend a lot of money to enroll their children in football, tennis and even golf classes. But here they fall into a misunderstanding again. We should note that the core of outdoor activities for myopia prevention and control is light. Although some studies have found that proper aerobic exercise can increase choroidal blood supply and delay the progression of myopia. But compared with sunlight, the effect is much less. Therefore, as long as we do 2 hours of outdoor activities every day, we don't need high-intensity exercise.

I often tell parents in the clinic that I don't have to play football or tennis for 2 hours every day (except, of course, I really like it). Walking outdoors or even sitting in a daze for 2 hours every day can effectively prevent and control myopia. Again, what matters is not what you do outdoors, but whether you get the sun outdoors.

4.Outdoor Activities Are Only Effective For Children Without Myopia , Is It Invalid For Children Who Are Already Short-Sighted?

Not only many parents have this misunderstanding, but also some ophthalmologists think so. The fact is that adequate daily outdoor activities can slow down the growth of ocular axis in both myopic and non myopic people. Then why is there such a saying that "outdoor activities are ineffective or ineffective for people who are already short-sighted"? This is because some popular science institutions have deviated from the interpretation of the paper research. Many research papers not only take the eye axis as an index to measure the growth of myopia, but also measure the diopter of myopia. However, many times, the growth of myopia is slower than the growth of ocular axis. We often encounter children whose ocular axis has increased by 0.2mm, but the degree of myopia has not increased for a time. (a crystal compensation mechanism is involved here, which will not be carried out here. It will be detailed in the future when there is a chance). Therefore, if we only measure the degree of myopia and ignore the growth of ocular axis, it is likely to come to the wrong conclusion that "outdoor activities are not helpful to myopia children".

In addition, a large number of myopia children who participated in the control study are already using low concentration atropine eye drops or peripheral defocus frame glasses, so even if they do not have enough outdoor activities, they will have a relatively good myopia prevention and control effect. This will also bias the research results, making it seem that outdoor activities are not so useful. In addition, some scholars believe that children with myopia wear frame glasses for a long time, which greatly reduces the sunlight (especially ultraviolet) entering their eyes during outdoor activities, thus reducing the effect of myopia prevention and control.

Therefore, children with myopia may affect the results of scientific research due to interference factors such as wearing glasses, eye habits and the choice of myopia prevention and control methods, but it is unscientific to unilaterally believe that "outdoor activities are ineffective for children with myopia". Outdoor activities are still effective for children who are already nearsighted.

5.No Sunscreen Measures Shall Be Taken For Outdoor Activities

Some parents choose to let their children go out when the sun is hot at noon, and do not take basic sunscreen measures. They are worried that if they wear sunglasses and sunshades, they will affect the intake of sunlight and reduce the effect of myopia prevention and control. In fact, they are too worried. First of all, although the existing qualified sunglasses can basically achieve more than 99% UV protection, this is only for the sunlight passing through the lens in the front. The light of outdoor activities is 360 degrees, and there is no dead angle in all directions. Ultraviolet rays can still enter the eyes through the gap between the face and the mirror frame. Unless wearing full cover goggles, ordinary sunglasses will not completely block the irradiation of ultraviolet rays.

Secondly, the research shows that in the light environment of more than 10000 lux (that is, sunny days), even wearing sunglasses, the illumination around the eyes can reach more than 3000 lux, which also meets the illumination required for myopia prevention and control.

Finally, as mentioned earlier, sunlight (especially ultraviolet light) is a double-edged sword for the eyes. Although it can prevent and control myopia, it will also damage eye cells. The pupil of children is larger than that of adults, the crystal is more transparent and the permeability to ultraviolet light is higher. Therefore, the photochemical damage of children's eyes caused by too strong ultraviolet light will be more severe than that of adults. Therefore, in the hot summer or when the sun is particularly fierce, children must wear sunglasses to reduce the damage to their eyes caused by excessive exposure to the sun. Of course, sunshades, sunscreen and other body protection also need to be done. After all, no one likes their children (especially girls) to be as exposed as coal balls for myopia prevention and control.