Experts: Parents should pay attention to the six signs of myopia in children and create a good visual environment

Children will habitually "squint" when watching TV or the blackboard; when reading or playing with mobile phones, they will involuntarily move closer to the target; after using their eyes for a long time, they will rub their eyes with their hands from time to time or blink frequently... As a parent, have you noticed these signs?

In this regard, People's Daily Online, in conjunction with the National Health Commission, invited Wang Ningli, Director of the Ophthalmology Center of Beijing Tongren Hospital, Chairman of the Public Health Ophthalmology Branch of the Chinese Preventive Medicine Association, and President of the Ophthalmology Branch of the Chinese Medical Association, Guo Xin, Chief Physician of Beijing Center for Disease Control and Prevention, and Li Yan, Chief Optometrist of Peking University People's Hospital, to popularize scientific knowledge on myopia prevention and control, and guide families and children and adolescents to do a good job in myopia prevention and control.

0 to 3 years old is the critical period for visual development

As for when to pay attention to children's vision and prevent myopia, Li Yan said: "In the process of human development, the period from birth to 3 years old is the period of the greatest change in refractive power. Most newborn babies have low hyperopia of 150 to 200 degrees. As they grow, the lens gradually becomes flatter and the eye axis gradually lengthens. By the preschool stage, the emmetropization process is gradually completed. 0 to 3 years old is the most critical period for visual development, and 0-12 years old is the sensitive period."

"With the popularity of electronic products and the adverse stimulation of electronic screens, the emmetropization process of children today is completed ahead of schedule. During this period, some children begin to develop myopia and the condition gradually worsens. The initial development of the eyeball of a 3-year-old child is completed, and the period from 3 to 6 years old is a relatively important developmental stage. We recommend that children should undergo basic vision tests starting at the age of 3." Li Yan said that children of this age can effectively cooperate with vision tests with guidance.

At the same time, Li Yan explained the vision of children from the perspective of age. He said: "Generally, the normal vision of a 3-year-old child is 0.5, a 4-year-old child is 0.6, a 5-year-old child is 0.8, and a 6-year-old child can reach 1.0. If a child's vision is found to be lower than that of children of the same age after a vision check at the age of 3, further examinations are required, such as dilation optometry, eye axis examination, corneal topography examination, etc."

"The primary school stage from 6 to 12 years old is the key prevention and control stage for myopia. After children start reading and doing homework, they are affected by long-term close-up eye use and low-light lighting. If they do not pay attention to eye hygiene at this time, myopia is likely to occur. During the middle school period from 12 to 18 years old, children's eye use reaches its peak and they have to face the pressure of the middle school entrance examination and the college entrance examination. We need to pay special attention to changes in vision and pay attention to the rate at which myopia worsens." Li Yan said.

"Therefore, in accordance with the spirit of the 'Implementation Plan for Comprehensive Prevention and Control of Myopia in Children and Adolescents' issued by the National Health Commission and other eight departments, we should establish refractive files, regularly record children's vision, axial length, corneal curvature and other refractive conditions, closely track children's visual health development, and achieve early detection, early intervention, and early treatment," he said.

Pay attention to the six signs of myopia

Li Yan introduced: "The precursors of myopia are mainly manifested in six aspects.

First, squint. When you squint, your eyelids block part of your pupil, reducing diffuse light and the effects of astigmatism, thereby temporarily increasing and improving your visual acuity.

Second, blink. Frequent blinking can relieve myopia to a certain extent and increase visual clarity.

Third, rubbing the eyes. When children cannot see the target clearly, they often rub their eyes with their hands in an attempt to see better.

Fourth, frown. Frowning is the way to improve vision by making both eyes work harder.

Fifth, pulling the eyes. When some children cannot see the distant target clearly, they often pull the skin of the outer corner of the eye outwards to achieve the same effect as tilting the head and squinting.

Sixth, tilting the head. It is common to tilt the head while watching TV. Tilting the head can reduce the interference and influence of some diffuse light. Some children even develop the habit of tilting their heads.

If the above symptoms occur, parents are encouraged to take their children to a regular medical institution for ophthalmology consultation to rule out myopia."

Regarding how to effectively prevent myopia, he said: "At present, the mechanism of myopia is still not fully understood. It is generally believed that myopia is the result of the combined effects of genes and environmental factors. Among them, myopia is closely related to outdoor exposure, close-range eye use and other factors. When children study in daily life, they should pay special attention to factors such as the use time of electronic products, lighting, reading and writing postures. It is recommended that they engage in outdoor activities for more than two hours a day, that primary school students should not study online for more than 20 minutes each time, and that middle school students should not study online for more than 30 minutes each time. When doing homework, they should maintain 'one foot, one fist, and one inch', that is, the distance should be one foot, the body should be one fist away from the desk, and the hand should be one inch away from the tip of the pen."

Li Yan also suggested: "For children whose schools are close to home, it is best to walk to and from school. If they live far from home, it is recommended to consider getting off the bus two stops in advance and then walking. For details, please refer to the "Guidelines for the Prevention and Control of Myopia in Children and Adolescents during Home Isolation during Infectious Disease Epidemics". Children who already have myopia should go to professional medical institutions for treatment in a timely manner, and they should also correct their eyes scientifically and follow up according to the doctor's treatment opinions."

Maintain correct reading and writing habits. Families need to be equipped with study tables and chairs.

Appropriate tables and chairs can protect eyesight. When parents configure study tables and chairs at home that match their children’s height, how do they judge whether the tables and chairs meet the requirements?

Guo Xin said: "Unsuitable desks and chairs will not only affect the visual distance of the eyes, but also increase the risk of children suffering from spinal curvature due to incorrect sitting posture, and will also increase learning fatigue, affect learning efficiency and other subsequent problems. At home, parents need to pay attention to the following three points when configuring desks and chairs.

First, the desk and chair for study cannot be replaced by other desks and chairs. For example, the dining table is usually too high, and the dining chair and ordinary chair are either too high or too low; and if you sit on the bed, it will be too low and too soft.

Second, refer to the "Height Range Table for Various Models of Desks and Chairs for Primary and Secondary School Students" (GB/T3976-2014) and prepare adjustable desks and chairs. The models of desks and chairs will be different for different children. Due to the different height proportions of children, parents must teach them in accordance with their aptitude when referring to the range table. For example, after adjustment, the child sits on a chair or stool, keeping the thigh and calf vertical at 90 degrees; at the same time, the back is straight, the upper arms are drooping, and the elbows are 3 to 4 cm below the table. Meeting this requirement means that the desk and chair match the child's height. If the desk is not adjustable, it can be adjusted according to the principle.

Third, after providing children with suitable desks and chairs, parents should also remind their children to maintain the correct reading and writing posture, such as keeping shoulders relaxed, upper back extended, upper arm and forearm at a 90-degree angle, wrists relaxed, and regular breathing. Also, some children cannot keep their hands an inch away from the pen tip, and some children even have to hold the pen tip. Therefore, with a desk and chair, parents should also observe their children more carefully in normal times. "

Four measures should be taken at home to create a good visual environment

In addition, Guo Xin also said: "In school, another major action is the visual environment, including the environmental conditions of lighting, and at home, we should pay attention to the following four points.

First of all, when placing a desk, make sure that the long axis of the desk is perpendicular to the window. When studying during the day, light should enter from the opposite side of the writing hand. For example, if you write with your right hand, the light should enter from the left side; if you write with your left hand, the light should enter from the right side. When the natural light is weak at night, give priority to using the ceiling light in the room; if the light is still insufficient, use a desk lamp for reading and writing to supplement it. According to the "Lighting Measurement Method", the average illuminance value of the desktop can be measured using a illuminance meter, and the value should not be less than 300 lux. If you don't have a illuminance meter at home, you can download the corresponding software on your mobile phone to measure it. There is also an upper limit for the value, which cannot be too low or too strong.

Secondly, when reading at night, you can't just use a desk lamp, you also need a ceiling light in the room. The desk lamp should be placed in front of the opposite side of the writing hand, and the color temperature should not exceed 4000K. Reading and studying at this color temperature will make children calm and improve their learning efficiency. When using a desk lamp with adjustable color temperature, the color temperature should be adjusted to below 4000K at night. Desk lamps for reading and writing that are not adjustable and have a color temperature higher than 4000K are not recommended for use at night.

Thirdly, bare lamps without lampshades should not be used for study lighting, and glass plates or objects that easily produce glare should not be placed on the desk. Some families put a glass plate on the desk, which we do not recommend.

Finally, it is recommended that parents learn to read product manuals when purchasing lamps. If the ceiling lights and desk lamps for reading and writing in the family room do not meet the relevant hygiene standards or product standards, it is recommended that parents replace them in time to create a good visual environment for their children.

Whether to wear glasses when studying with low myopia requires specific analysis of the specific situation

Regarding the question of whether children with low myopia should wear glasses when reading or doing homework after getting them fitted, Li Yan said: "Low myopia refers to myopia below 300 degrees. Whether to wear glasses when reading or doing homework needs to be analyzed on a case-by-case basis. When looking at close objects, the human eye needs to adjust to see the words on the book clearly. This process is directly involved in the human eye lens. The lens is like a convex lens. When looking at close objects, the lens becomes convex, and the increased refractive power makes close objects clearer. The reading distance that people are accustomed to is 33 to 40 centimeters. In order to see the words on the book clearly, for a reading distance of 33 centimeters, the human eye needs 3D (diopter) of adjustment power."

"But people like to be lazy. At a reading distance of 33 cm, many people can see clearly with 2.5D of accommodation, which will cause a difference between the actual accommodation power and the theoretical value, which is called "accommodative lag" in medicine. As a result, the position of the clearest image is behind the retina. This refractive state is extremely unfavorable for the control of myopia progression. When looking at close objects, the visual axes of both eyes will converge in a process called convergence. The convergence function is an issue that needs to be considered in the process of fitting and wearing glasses." Li Yan said.

"Recent studies have found that myopia patients do not have excessive accommodation, but insufficient accommodation, decreased accommodation sensitivity, and more obvious accommodation lag. Therefore, from a clinical perspective, intervention measures should start with improving accommodation power and accommodation sensitivity and reducing accommodation lag." Li Yan also said, "The position of the two eyes when looking at things is called eye position, which is also a problem that should be carefully considered during the glasses fitting process. In the general population, there are very few eyes that are completely straight, and the eyes will have some degree of esotropia or exotropia, which is different when looking at far and near. This is also something that needs to be considered during the glasses fitting and wearing process. For the above situations, you need to go to a regular hospital to see an optometry specialist for judgment, and you need to check the specific indicators of binocular vision function before you can make a decision."