The "culprit" for high myopia is not sweets, but...

Recently, a 20-year-old girl named Xiao Li (pseudonym) from Chengdu had myopia of up to 1500 degrees. Doctors diagnosed that her myopia worsening was related to excessive intake of sweets. Once this report was published, it attracted widespread attention from the public, and netizens were condemning sweets such as candy, cakes, and ice cream.

Can excessive intake of sweets really make myopia worse? Is it the main cause of high myopia? What are the factors that lead to high myopia? Science and Technology Daily reporters interviewed relevant professionals with these questions.

Have you ever played with a basketball or a volleyball?

Eating too much sweets can cause sclera softening and eye axis lengthening

"Excessive intake of sweets is indeed a factor that worsens myopia, but it is not the main factor that causes high myopia. There are many factors that cause myopia, such as improper eye posture, long-term excessive use of eyes in dim ambient light, children's picky eating, etc., but relevant studies show that these factors often do not cause high myopia." Chen Siyang, chief ophthalmologist at the China-Japan Friendship Hospital, said in an interview with Science and Technology Daily that the so-called high myopia usually refers to myopia of more than 600 degrees. Xiao Li's high myopia of 1,500 degrees cannot be attributed solely to his love of sweets.

File photo. Image source: Xinhua News Agency reporter Li Bo/Photo

Of course, the role of sweets in the progression of myopia cannot be ignored. How do sweets become an "accomplice"? Chen Siyang further explained that eating too much sweets can easily soften the sclera of the eye, causing the eye axis to lengthen, thus aggravating myopia.

The sclera is one of the main components of the eyeball wall. The white of the eye that we can see is actually part of the sclera. The sclera wraps around almost the entire eyeball like a thick wall, connecting to the cornea in front and the sheath of the optic nerve in the back. The sclera has a tough structure and plays a role in supporting and protecting the tissues inside the eye.

When the sclera softens, its support will decrease, and the eyeball will be more easily deformed than normal people. Chen Siyang made an analogy: if a normal person's eyeball is regarded as a basketball, then the eyeball with softened sclera is more like a volleyball. Under the same conditions, if the basketball and volleyball are squeezed with the same force, the volleyball will definitely be more easily deformed.

If you don't pay attention to scientific eye use, the eyeball with softened sclera will be more likely to stretch under the action of intraocular pressure, thus causing and aggravating axial myopia. Axial myopia is what we usually call true myopia, which cannot be restored once it is formed.

Data map. Image source: Guangming Daily Zhang Xianda/drawing

Chen Yuchuan, chief ophthalmologist at the West China Fourth Hospital of Sichuan University, gave an answer to the question of "eating too much sweets will soften the sclera". He said that long-term intake of sugary foods will produce a lot of acidic substances during the metabolic process of digestion and absorption. These acidic substances will react with calcium ions in the body. Calcium exists in the body in an alkaline state. The neutralization reaction between acid and alkali will lead to a decrease in blood calcium, thus affecting the development of the eyeball wall. During the development of children, the main components of the eyeball wall, such as the sclera, need to take in a relatively large amount of calcium for a long time. If calcium is lacking, the eyeball wall may be thin and weak.

Chen Siyang also emphasized that excessive intake of sweets often causes more "persecution" to children's eyes than adults. First, children are more likely to rely on sweets, and second, children's eyeballs are in the development stage and are "laying the foundation", and are relatively sensitive to various elements needed in the growth process of the body. If adults' eyes are "laid a good foundation" when they are young, even if they are addicted to sweets when they grow up, the impact on their vision is not very obvious. According to relevant media reports, although Xiao Li, the protagonist of this hot event, is an adult in his 20s, he has loved eating sweets since he was a child. It can be seen that he did not "lay a good foundation" when he was a child.

Of course, there are many other harms of consuming too much sweets, such as obesity, skin aging, etc. As the saying goes, everything should be done in moderation, and high-calorie sweets are no exception.

Do your parents wear glasses?

The culprit of high myopia is genetic factors

According to relevant reports, Xiao Li said that she had myopia since she was a child, and she paid attention to eye hygiene and knew how to protect her eyes properly. However, her myopia degree continued to increase.

"In the final analysis, sweets are at most an 'accomplice' of myopia, while the 'culprit' that leads to high myopia is often genetic factors," said Chen Siyang.

High myopia is an autosomal recessive hereditary disease. In other words, if there are many parents, relatives or other family members with myopia of more than 600 degrees, the probability of their children suffering from high myopia will also increase. "Therefore, Xiao Li's parents or other family members may also have high myopia." Chen Siyang said.

In 2020, a survey of 376 teenagers in Jiamusi area of ​​Heilongjiang Province showed that the rate of vision abnormalities among children whose parents were myopic was 19.24% higher than normal ones.

It is worth mentioning that only parents with high myopia have a genetic tendency, while low or moderate myopia is basically not inherited. Therefore, using eyes scientifically and controlling myopia is not only beneficial to oneself, but also to future generations.

In addition, Chen Siyang also emphasized that improper correction is very common in daily life, which can easily lead to high myopia. The so-called improper correction means that the eyes are already myopic, but have not received scientific and appropriate vision correction, such as wearing glasses with the wrong degree (low or high is not scientific), not wearing glasses in time (some people mistakenly believe that the later they wear glasses, the better), etc. These situations will make the eyes more easily fatigued, and the eye muscles are in a wrong adjustment state for a long time. Over time, the degree of myopia will increase, making it easier to break the 600-degree "red line" and develop into high myopia.

Medical staff conduct vision tests for primary school students at Xili Primary School in Shijiazhuang (file photo). Image source: Xinhuanet

In this regard, Chen Siyang suggested that we should pay close attention to the changes in vision of people who are not myopic or have low myopia (especially children). It is recommended that children test their axial distance every six months, and adults test their axial distance once a year. In addition, scientific optometry is the most important prerequisite for scientific glasses fitting and vision correction. It is recommended to go to a regular medical institution for medical optometry, and it is not recommended to go to an eyewear store for optometry. The reason is that the professionalism of optometry in an eyewear store cannot be guaranteed, and many eye problems cannot be detected. For young children who are having their first eye exam, it is recommended to go to a regular medical institution for mydriasis optometry, which can obtain eye data that is closer to the real thing. Mydriasis optometry is also recommended for people whose degree increases too quickly.

Eyes are the windows to the soul. As the National Eye Care Day is approaching, please tighten the string of eye care again and don't let the window of the soul be covered with dust.

◎ Yu Ziyue, intern reporter of Science and Technology Daily

Source: Science and Technology Daily

Editor: Huang Lei

Review: Yue Liang

Final judge: He Yi