■Fei Ping
Every winter and summer vacation and before and after school starts, the major eye clinics will always be full of eyes full of primary and secondary school students waiting for medical treatment. Parents take their children to the hospital to check their eyes or replace their myopia glasses.
Why is vacation a high-risk period for the occurrence and aggravation of myopia in primary and secondary school students?
It is mainly related to bad eye habits, such as writing homework or reading a book, etc., using the eyes for a long time, watching TV, computers, mobile phones and other video screens for too long, and not having enough outdoor activities in the sun, etc., will increase the risk of myopia.
Nowadays, parents pay more and more attention to their children's vision health, and there are many knowledge points on how to prevent myopia on the market, but you may not know all of these ten problems.
1 How long does it take to "control the screen"?
Everyone knows how to prevent myopia by controlling screen time, but how long is it appropriate to control the screen?
We recommend that the cumulative entertainment video time of school-aged children and adolescents should not exceed 2 hours a day. If it can be controlled within 1 hour, the effect of preventing myopia will be better, and a break of 3-5 minutes in the middle of half an hour.
The online learning time shall not exceed 2.5 hours per day for primary school students and no more than 20 minutes each time; for middle school students, no more than 4 hours per day and no more than 30 minutes per time.
In addition, when choosing electronic products, the size of the screen is very important. To reduce eye discomfort and fatigue, the suggested priority is: projector, TV, computer, tablet, and finally mobile phone.
2 Are cloudy outdoor activities useful?
In particular, the key to preventing myopia is not to look at mobile phones less, but to increase more outdoor activities.
Current research believes that sunlight is full-spectrum light, with high intensity, and the human eye naturally adapts.
At the same time, natural light can promote the release of dopamine in the retina, thereby delaying the growth of the eye axis and helping to prevent myopia.
Outdoor activities can also help protect vision because of the wide field of vision, reducing peripheral defocus myopia.
Therefore, indoor sports without enough sunlight and limited field of vision cannot replace outdoor activities.
Whether it is sunny or cloudy, children can be exposed to natural light outdoors during the day and have a wide field of vision, which can more effectively prevent myopia.
The recommended time for outdoor activities is no less than 2 hours a day, and longer is recommended for children and adolescents with myopia.
3 Is it okay to rest your eyes and look through the window?
If you need to isolate yourself at home due to epidemic prevention and control, you can “bathe in the sun” through balconies, windows or from your home yard, and get in touch with natural light, which will also help relieve visual fatigue.
4 Is it necessary for children to wear blue light blocking glasses?
In fact, the relationship between children's use of electronic video terminals and myopia is more about reading distance and reading time, and has nothing to do with blue light.
Blue light may be damaging to the retina, but blue light may also have a protective effect on myopia.
The intensity of blue light emitted by electronic video terminals is very weak (hundreds of times weaker than natural light), if not staring at mobile phones or computers for a long time (more than 8 hours) every day (children generally do not use computers or mobile phones for such a long time) , it is not necessary to wear anti-blue light glasses when using electronic video terminals rationally.
People with macular diseases, such as age-related macular degeneration, macular hole, diabetic fundus disease, etc., need more blue light protection.
5 Is it easy to be short-sighted if you eat too much sugar?
The growth and development of the eyes requires rich nutrition. Children in the developing period must have a balanced diet, not picky eaters, not partial eclipse, eat more fruits and vegetables, and eat high-quality protein such as fish, soy products and eggs, and also eat more carrots , blueberries and other foods rich in vitamins beneficial to the eyes have a positive effect on maintaining normal eye growth and visual function.
It is recommended to eat less sweets and sugar-sweetened beverages.
Regarding the statement that "eating too much sugar is easy to be nearsighted", the main basis is that sweets can easily increase blood sugar, change the osmotic pressure of crystals, and induce myopia, and excessive consumption of sweets can easily lead to other metabolic disorders such as overweight and obesity. Therefore, it is recommended that children Eat less as well.
6 Does lack of sleep affect vision?
Studies have shown that less sleep time and later sleep time at night will increase the risk of myopia.
Therefore, it is recommended that primary school students sleep no less than 10 hours, junior high school students no less than 9 hours, and high school students no less than 8 hours.
In the student days, it is necessary to avoid going to bed late and getting up late, and develop a regular work and rest.
7 Do you usually do eye exercises at home?
Eye exercises are a way to relieve eye fatigue and relax your eyes. You can choose to do contact eye exercises or non-contact eye exercises when you are reading and writing at close range for 30-40 minutes or video screen activity for 20-30 minutes.
【Contact Eye Exercises】According to the daily eye exercises at school, it includes acupuncture at Zanzhu, Jingming, Sibai, temple, eye socket, Fengchi, earlobe, Toe grip 6 knots.
Before doing eye exercises, cut your nails, clean your hands, and make sure you close your eyes carefully.
When doing eye exercises, you should find the correct acupuncture points, and the technique should be gentle, with a slight soreness.
【Non-contact eye exercises】This not only avoids the risk of infection caused by hand contact with the eyes, but also provides a new way to rest the eyes according to the season.
The specific steps include: opening and closing the eyes (close the eyes for four beats and then open the eyes), cross movement (look left, right, up, and down with the eyes), circle the eyes (the eyes rotate counterclockwise and clockwise), and alternate far and near ( Arms straight forward, eyes alternately looking at fist and distance) 4 knots.
8 Is there a signal that the child's eyesight has deteriorated?
Parents should pay attention to their children's eyesight. If they find that their children have symptoms such as dry eyes, foreign body sensation, burning sensation, itching, photophobia, red eyes, and eye pain, they should stop viewing the screen; if the symptoms cannot be relieved, go to the hospital if necessary. See a doctor.
For young children, parents should consciously observe from time to time or take the initiative to ask whether they have the above symptoms.
When it is found that the child has myopia-related symptoms such as tilted head, frequent squinting, winking, etc., it is advisable to rest and exercise in a timely manner, and go to the hospital if necessary.
9 Are all kindergarten children mildly farsighted?
The refractive state of kindergarten children should be mild hyperopia, the refractive power is about +1.00D, and the uncorrected visual acuity is about 0.6-1.0.
For example, the uncorrected visual acuity of a 5-year-old child is 0.8, and the dioptric diopter is +1.50D, indicating that his refractive development is basically normal, and there is no need to correct hyperopia.
If dilated optometry, the diopter is -0.50D to +0.50D, indicating that the risk of myopia will be greatly increased in the future, and attention should be paid to it.
Generally speaking, for preschool children, they can regularly come to the hospital for optometry during the winter and summer vacations every year.
If the vision changes are not obvious, you can follow the doctor's instructions to standardize the optometry.
If the child is over 12 years old and the progression of myopia is not obvious, it can also be reviewed once every six months.
10 Myopia occurs, what should I do?
Myopia can be corrected, but it is difficult to cure.
If you find myopia, you must adjust your mentality, don't be superstitious, go to a regular ophthalmic medical institution for examination, and perform dilated optometry if necessary.
The doctor will give the best treatment plan according to the situation.
Currently available methods for myopia prevention and control include wearing frame glasses, orthokeratology lenses (commonly known as OK lenses), low-concentration atropine eye drops, etc., which have certain effects in controlling the progression of myopia, but are not suitable for everyone. Choose and use it under the guidance of a doctor, and review it regularly.
If myopia is not scientifically controlled, myopia will deepen regardless of whether I wear glasses or not.
If myopia has already occurred, failing to wear glasses correctly in time will accelerate the growth of myopia.
The correct approach should be scientific correction under the guidance of a doctor. If you can't see clearly, you need to wear appropriate glasses as soon as possible.
(The author is the deputy chief physician of the Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine)