Can drinking boiled foxtail grass cure myopia? Netizens are arguing over the truth...

Rumor: "Drinking water boiled with foxtail grass can cure myopia!"

Recently, a piece of content related to "a woman using dogtail grass to boil water to treat her child's myopia" was widely circulated on the short video platform, attracting many netizens to watch. Many people believed it to be true and liked, collected and forwarded it.

Rumor analysis: This statement is very unscientific.

At present, no medicinal ingredients have been found in dogtail grass that can improve or eliminate myopia, and drinking dogtail grass water cannot cure myopia.

On a certain short video platform, there was a video saying that a woman saw on the Internet that dogtail grass has the effect of improving eyesight, so she boiled dogtail grass in water and gave it to her child to drink. After drinking it for a week, the child felt that he could see clearly the words on the blackboard that he could not see clearly before while sitting in the same position, so he believed that dogtail grass can cure myopia.

Image source: Screenshot of short video platform

After the video was released, the number of likes and reposts reached more than 100,000, and the number of comments and favorites also reached tens of thousands. Many netizens left messages in the comment area, eager to try it, and many netizens also raised doubts. So, can drinking dogtail grass boiled water really cure myopia?

Image source: Screenshot of short video platform

Can drinking boiled foxtail grass water cure myopia?

To know the answer to the above question, today we first understand what myopia is. When our eyes are in a relaxed state, parallel light (5 meters away) passes through the eye's refractive system and forms a focus in front of the retina. This optical state of the eye is called myopia. The characteristic of myopia is that close vision is clear, but far vision is not clear.

Figure 1 The upper picture shows emmetropia, and the lower picture shows myopia. Source: Reference [6]

According to the classification of eye regulation, myopia can be divided into three categories:

1. Pseudomyopia: Due to accommodation spasm, the emmetropia or hypermetropia eye shows temporary myopia. After the pupil is dilated with atropine, the myopia disappears and the emmetropia or hypermetropia appears.

2. True myopia: Myopia does not decrease after mydriasis with atropine or the decrease is <0.50D (50 degrees).

3. Mixed myopia: After mydriasis with atropine, the refractive power decreases by ≥ 0.50D (50 degrees), but emmetropia is not restored.

In the video, the woman said that her son was diagnosed with mild myopia and loved to blink, so she boiled water with dogtail grass and gave it to the child to drink. After drinking it for a week, the child said that he could see the words on the blackboard clearly when sitting in the same position. It is clear that there is no drug ingredient in dogtail grass that can improve or eliminate myopia, and there is no causal relationship between drinking dogtail grass water and improving the child's vision. So why did the child say that after drinking dogtail grass water, he could see the words on the blackboard clearly when sitting in the same position? Some netizens speculated in the comments that it might be because the child did not want to drink dogtail grass water anymore.

Image source: Screenshot of short video platform

In addition to the above speculation, we think there is another possibility: the eyes of the children who drank dogtail grass water may be pseudomyopia. Long-term, close-range excessive use of the eyes stimulates the eye's adjustment or ciliary muscle spasm, which leads to an increase in the eye's refractive power, manifesting as myopia. The child may have pseudomyopia, which leads to a decrease in naked eye vision and difficulty seeing the blackboard clearly. After fully relaxing the eyes, the pseudomyopia disappears, and the naked eye vision basically returns to normal, so the words on the blackboard can be seen clearly at the same distance.

Let's assume a scenario: a child may develop pseudomyopia after reading and writing at close range for 40 minutes during class, and the words on the blackboard will become unclear when he looks up. When the get out of class is over, the child drinks a few sips of Coke during the break, then goes to the playground to relax and look into the distance for 10 minutes. After the eyes relax, the transient pseudomyopia disappears, and when the child returns to the classroom and sits in the same position to look at the words of the same size on the blackboard, they become clearer than before. After so many repetitions, can we conclude that drinking Coke during breaks can cure myopia? Obviously not.

The scientific method to determine whether a drug or measure is effective is the randomized controlled trial (RCT), which is a means of testing the effectiveness of a certain therapy or drug in medical and health services, and is particularly commonly used in medicine, biology, and agronomy.

The basic method of randomized controlled trials is to randomly group the subjects and implement different interventions on different groups to compare the effects. This method can avoid various biases that may occur in the design and implementation of clinical trials to the greatest extent, balance confounding factors, improve the effectiveness of statistical tests, and has many advantages. It is recognized as the gold standard for evaluating intervention measures. When we understand this scientific experimental idea, we can easily identify scams or rumors on the Internet or in reality.

Is there any medicine that can treat myopia?

Now let’s get back to the issue of myopia. Is there any medicine that can treat myopia?

The answer is that there is currently no drug that can cure myopia, but there are drugs that can detect whether pseudomyopia exists and slow the progression of myopia.

When parents take their children to the hospital for myopia examination, ophthalmologists usually recommend that their children undergo mydriasis optometry. Mydriasis optometry is called ciliary muscle paralysis optometry, which is internationally recognized as the gold standard for diagnosing myopia. It is recommended that children under 12 years old, especially those who are undergoing optometry for the first time or have hyperopia, strabismus, amblyopia and large astigmatism, as well as patients who are found to have unstable accommodation, abnormal corrected vision and cannot be explained by other eye diseases during optometry, should undergo ciliary muscle paralysis optometry. When the ciliary muscle is paralyzed and relaxed, the pupillary sphincter is often paralyzed as well, causing the pupil to dilate, so it is commonly known as "mydriasis".

For example, if a child's eyesight test result before dilation is 150 degrees myopia, but after dilation, the eyesight test result is only 100 degrees myopia, then the disappeared 50 degrees of myopia is pseudomyopia, and the remaining 100 degrees of myopia is true myopia.

Commonly used drugs for checking for pseudomyopia include 1% atropine eye ointment or gel, 1% cyclopentolate hydrochloride eye drops, and 0.5% compound tropicamide eye drops.

1% atropine eye ointment or gel has the strongest ciliary muscle paralysis effect and lasts the longest. It is suitable for myopic children under 6 years old, especially patients with hyperopia and strabismus and amblyopia. Atropine eye ointment or gel is the first choice for mydriasis.

The ciliary muscle paralytic effect of 1% cyclopentolate hydrochloride eye drops is second only to atropine eye ointment or gel, and the duration of action is shorter. It can be considered as a substitute when atropine eye ointment or gel is not acceptable, and as a mydriasis eye test for myopic children aged 7 to 12 years.

Compound tropicamide eye drops have a short duration of action and the weakest ciliary muscle paralysis among the three. It is suitable for people aged 12 to 40 years old and can also be used clinically for mydriasis eye refraction in myopic children aged 7 to 12 years old.

Some parents worry that these drugs will damage their children's eyes and refuse to have mydriasis refraction examinations. This is completely unnecessary. Without mydriasis refraction, the child's eyes cannot be measured, which will delay diagnosis and treatment. After mydriasis, the child's eyes are in a completely relaxed state, because dilated pupils will cause symptoms such as blurred vision, fear of light, and fear of opening the eyes. These symptoms will disappear as the drug effect subsides and the pupil size returns to normal.

It should be noted that these drugs are prescription drugs and should only be used before an eye examination. The doctor will decide which mydriatic drug to use based on the child's age, refractive status, whether there is strabismus, amblyopia, medication contraindications, etc. Parents should not purchase and use them at will.

In addition, 0.01% atropine sulfate eye drops are a drug that has been proven by evidence-based medicine to effectively delay the progression of myopia. In March 2024, it was officially approved by my country's National Drug Administration for the prevention and control of myopia in children and adolescents. Note that the statement here is to effectively delay the progression of myopia, not to eliminate myopia. Low-concentration atropine eye drops need to be used in a standardized manner under the guidance of an ophthalmologist, and regular check-ups should be performed as directed by the doctor.

Therefore, parents must keep their eyes open and never believe in the exaggerated propaganda of some so-called health products, Chinese herbal remedies, eye patches, therapeutic devices, etc. that can cure myopia. Not only will they not work, but they may also cause physical harm to children and delay regular diagnosis and treatment.

How to protect children’s eyes in daily life?

The occurrence of myopia is influenced by both environmental and genetic factors. We cannot change genetic factors, so it is crucial to improve environmental factors.

1. Reduce close-up eye use

Close-up eye use is recognized as an important risk factor affecting the development of myopia and is positively correlated with the development of myopia. In addition to the total amount of close-up eye use, long duration of close-up eye use (>45 minutes) and short reading distance (<33 cm) are also risk factors for myopia. Parents can use scientific means to supervise and cultivate good close-up eye use habits in children and adolescents.

2. Increase outdoor activities

Outdoor activity time is negatively correlated with the incidence and progression of myopia and is an important protective factor for myopia. Therefore, it is recommended that children start to increase their outdoor activity time before school age, with at least 2 hours of outdoor activity per day. Students should do more outdoor activities during breaks, and go outdoors more after school and on weekends under the leadership of their families and with the participation of their parents or guardians, so as to reach the daily outdoor activity time.

3. Good reading and writing habits

Bad reading and writing habits are risk factors for myopia. Children and adolescents who tilt their heads when writing and hold their fingers close to the tip of the pen (<2 cm) have a higher prevalence of myopia. We should cultivate good reading and writing habits, keep the fingertips of the pen one inch (3.3 cm) away from the tip of the pen, the chest one fist (6-7 cm) away from the table, and the book one foot (33 cm) away from the eyes. Keep a correct sitting posture when reading and writing, and do not read while walking, riding or lying down.

4. Good lighting

Reading and writing should be done in a well-lit environment. The average illuminance of the desktop should not be less than 300 lux, and should be adjusted based on the type of work and the font size. Do not read or write in an environment that is too dark or too bright to avoid glare and eyestrain.

5. Do eye exercises

Eye exercises can relieve eye fatigue symptoms. Clinical studies have shown that doing eye exercises can reduce accommodation lag and improve subjective symptoms of visual fatigue compared to not doing eye exercises, thus helping to delay the occurrence and development of myopia.

6. Others

Reduce excessive and unscientific use of electronic products, increase sleep time, maintain a good circadian rhythm, maintain a balanced nutrition, etc.

Looking in the mirror of rumors

In daily life, we often hear that there is a "miracle cure" or "special medicine" for a certain disease. Many people who are suffering from illness will inevitably be misled and believe it to be true.

I hope that everyone can remain calm and rational when facing health problems, and not be easily confused by false information, and not blindly follow the trend of treatment. The advice and diagnosis of professional doctors are the references worthy of our trust.

References

[1] Yang Zhikuan. Clinical Optometry[M]. Beijing: Science Press, 2008:144-145

[2] Strabismus and Pediatric Ophthalmology Group, Ophthalmology Branch of the Chinese Medical Association. Expert consensus on optometry and safe medication for ciliary muscle paralysis in Chinese children (2019) [J]. Chinese Journal of Ophthalmology, 2019, 55(1): 7-12.

[3] Chinese Medical Association Ophthalmology Branch Optometry Group, Chinese Medical Association Ophthalmology Branch Optometry Committee. Expert consensus on the application of low-concentration atropine eye drops in the prevention and control of myopia in children and adolescents (2024) [J]. Chinese Journal of Optometry and Visual Science, 2024, 26(09): 641-648.

[4] Notice of the General Office of the National Health Commission on the issuance of the Guidelines for the Prevention and Treatment of Myopia (2024 Edition) https://www.gov.cn/zhengce/zhengceku/202406/content_6957665.htm

Author: Liu Gang, deputy chief physician of ophthalmology, Qilu Hospital, Shandong University, Qingdao Branch

Review丨Jin Xiuming, Deputy Director of the Ophthalmology Center, Zhejiang University Second Hospital