Zhao Tong

  The topic of "Study found that playing with mobile phones before going to bed hurts eyes and shortens life" has recently appeared on Weibo.

The origin of this claim was an English-language science and technology report that featured a study recently published in Nature Communications.

Researchers at the Buck Institute on Aging in the United States found that dietary restriction can prolong the lifespan of fruit flies by activating some rhythm genes, and an unexpected discovery is that the expression of these rhythm genes is related to photoreceptors; then, the researchers let Drosophila long-term in the dark environment, reduce the stimulation of light on its visual cells, the result is the lifespan of Drosophila extended.

The researchers believe that this suggests that the stress and activation of photoreceptors can hinder the extension of lifespan in Drosophila.

  Looking at this conclusion alone, it is indeed worrying.

In the modern living environment, everyone is inseparable from electronic products such as mobile phones and computers, and it is a habit of many people to use mobile phones before going to bed at night.

So, how to avoid the damage of light stimulation to the eyes as much as possible?

Does the human eye receive too much light stimulation really affect lifespan?

  1 The mind is relaxed, the eyes are "overworked"

  Many people have this feeling: after a busy day at work and with a baby, they can only enjoy a relaxing and quiet time before going to bed.

For them, the mobile phone is like a tool to enhance the atmosphere of solitude, regardless of whether it is watching news, videos, novels or chatting.

That is to say, the mobile phone carries the function of psychological comfort at this time.

  However, in contrast to the psychological ease, the eyes are tense.

Because people's eyes are open all day, except when they are asleep, they are working when we are working, and when we think we are "resting", they are still working.

Moreover, when you look at your phone before going to bed at night, because there is no other thing in the "queue" waiting to be processed, you often forget the time when you look at it, and one or two hours are fleeting, which increases the burden on your eyes.

  What happens to your eyes when you look at your phone at night?

  From a medical point of view, first, blinking is reduced when the eye is focused on the phone, the tear film on the surface of the cornea becomes unstable and easily ruptures, and the tear fluid evaporates quickly.

At that time or the next day, when symptoms such as dryness, fatigue, tearing, and reluctance to open your eyes appear, it is likely that dry eye syndrome has followed.

There is also a term in medicine called "video terminal syndrome", which means a combination of various discomforts caused by looking at electronic screens such as mobile phones and computers. This is directly related to the time of screen use. The longer the viewing time, the symptoms In severe cases, corneal epithelial damage may occur, and even symptoms such as eye pain and headache may occur.

  Secondly, when the eyes are used at close range for a long time, the ciliary muscle will continue to contract and spasm, causing obvious symptoms of fatigue and even dizziness in people of all ages.

For adolescents, long-term close use of the eye and continuous contraction of the ciliary muscle will induce the continuous progression of myopia; for middle-aged and elderly people, this may reduce the elasticity of the lens, aggravate eye blemishes and even cataracts.

  Third, in the case of insufficient light at night, the pupil will naturally dilate. If you have special anatomical structures such as shallow anterior chamber and narrow angle of the chamber, long-term exposure to the dark environment may induce glaucoma, which is manifested as sudden vision loss, Severe pain in the eyes, even headache, nausea, vomiting and other symptoms.

  2 Eye protection mode cannot completely eliminate the effects of blue light

  In addition to the effects on the eyes, one of the most common negative effects of looking at mobile phones at night is sleep disturbance.

This principle is well explained.

Looking at the mobile phone before going to bed, all the information transmitted to the brain will arouse the cerebral cortex and sympathetic nerve excitation to varying degrees, which will lead to the disturbance of the autonomic nervous system and the biological clock.

Research has also proved that blue light released by mobile phone screens can inhibit the synthesis of melatonin (a hormone in the body that induces natural sleep), thereby aggravating sleep disorders such as difficulty falling asleep, easy waking and dreaming, and reducing sleep quality.

  Now many electronic products have launched an eye protection mode. By adjusting the color temperature of the screen, the screen becomes "yellow". The mobile phone uses software algorithms to highlight red and green lights in the display, thereby reducing the output of blue light to a certain extent and increasing the viewing rate. The comfort of the phone.

However, don't think that switching to eye protection mode will protect your eyes.

On the one hand, the eye protection mode can only block a certain degree of blue light, but not all of it. On the other hand, the screen in the eye protection mode will be relatively dark, and the display contrast will also be relatively reduced, which makes the eyes more likely to feel tired over time. .

Therefore, the most effective eye protection method is still to reduce the time spent looking at electronic screens, rather than relying on the so-called eye protection mode.

  Some people say that it is good for the eyes to make the background color of the mobile phone screen green. Is this statement scientific?

Color psychology believes that green can make people feel comfortable and calm. The reason may be that green light is in the center of the visible spectrum, and the human eye is more sensitive to the recognition of green, but there is no clear evidence-based medical evidence for its eye protection effect.

  In addition, the poor posture of brushing the mobile phone before going to bed may lead to lumbar and cervical spine diseases.

Some people are accustomed to placing soft pillows on the back of their necks and backs when looking at their mobile phones, which is comfortable for short-term use, but maintaining this posture for a long time, the lumbar spine is suspended and lacks effective support, which will increase the pressure of the lumbar intervertebral disc and induce lumbar intervertebral disc herniation.

Similarly, the long-term forward flexion and stress of the cervical spine can also cause stiffness and pain in the cervical spine, which can induce cervical spondylosis.

  3 There is no evidence for the theory of "hurting life"

  Brushing your phone at night is indeed bad for your eye health, but it's debatable when it comes to affecting your lifespan.

  The research conclusion mentioned above is that the research object is Drosophila.

Drosophila has a very short lifespan. In life science research, it is an ideal research model for genes, especially aging-related genes. However, compared with humans, the differences in body size and biological affinities are all significant. huge.

Therefore, it is not advisable to simply extrapolate the results obtained from the fruit fly experiments to humans.

  Careful reading of the research paper can be found that the conclusion of the article is prudent, and the relationship between the visual system and lifespan is very complex from a macroscopic level, and it is far from being thoroughly studied by an experiment.

In a sense, the visual system consumes a lot of energy and resources for living organisms, but at the same time it is necessary for most organisms to forage, court, and survive. Therefore, it cannot be simply said that the visual system accelerates aging.

Objectively speaking, there is a complex relationship between the visual system and aging, and the two have also reached a delicate balance in the evolution of life.

  On the other hand, the results of research are sometimes inspiring, but they themselves can only stay in the laboratory and cannot be generalized to the real world, even the real world of fruit flies.

Drosophila in the laboratory can delay aging by being in the dark for a long time, but in the real world, due to the loss of the visual system, the fruit flies cannot normally forage for food and avoid natural enemies, which will shorten their lifespan.

Similarly, in the real human world, there are many factors that affect life expectancy. Even if the activation of photoreceptor cells in the human eye is indeed negatively correlated with lifespan, it is difficult to exceed the influence of genetic, environmental, medical conditions and other factors to show a statistical difference in .

  Therefore, "playing with mobile phones before going to bed will shorten lifespan" is not a scientific judgment.

  4 The key to healthy use is to control the duration

  During the day, you are obviously exhausted, but you lie in bed at night and use your mobile phone until late at night. This behavior is also known as "retaliatory sleep procrastination" in medicine.

According to related research, this behavior may be a psychological compensation to combat the stress of the day.

Generally speaking, people who are more stressed during the day and who often suppress their desires are more prone to retaliatory sleep procrastination.

Retaliatory sleep procrastination gives the illusion of being in control of your life, but in fact, reduced sleep time can lead to a series of side effects such as decision-making and cognitive decline.

  In the era of mobile Internet, people's lives are more and more inseparable from mobile phones, but we can use mobile phones as healthy as possible.

  For office workers, the key to healthy use of mobile phones is to control the length of time spent looking at mobile phones. When using mobile phones to relax before going to bed, you need to remind yourself to stop in moderation, try not to exceed half an hour; do not stare at mobile phones and computer screens for too long during the day. , If you feel your eyes are tired, stand up and move around and look into the distance.

  For the prevention and control of myopia in young people, there is a "20-20-20" rule, that is, after using the eyes at close range for 20 minutes, look out 20 feet (about 6 meters) away for more than 20 seconds.

We can also extend this rule to the time spent watching electronic screens, which can greatly relieve eye fatigue and discomfort.

Children try not to use mobile phones, let alone watch electronic screens at night.

  The elderly need to pay special attention to not looking at their mobile phones in a dark environment, not to turn off the indoor ambient lights to save power or to worry about affecting the rest of the family, and at the same time adjust the brightness of the mobile phone screen appropriately to match the ambient brightness.

In addition, pay attention to the posture of looking at the mobile phone, do not lie down for a long time, so as not to aggravate the damage to the neck, waist and other parts.

  Finally, remind people who wear contact lenses to remember to take off their contact lenses before going to bed when looking at their mobile phones.

If you accidentally fall asleep, wearing contact lenses all night may cause corneal epithelial damage, conjunctivitis and other problems.

  In this era, all kinds of visual information are overwhelmed, which brings great challenges to eye care.

70%-80% of the information obtained by humans comes from vision, so we must protect this important sensory organ.

If your eyes are sore and tired after looking at the electronic screen for a long time, this is an early warning signal from the body.

We can try to change the habit of using eyes, reduce the time spent looking at the screen, and apply a hot compress before going to bed at night. For example, using a hot compress can help relax the nerves and muscles of the eyes and relieve fatigue.

  (Author: Deputy Chief Physician, Department of Ophthalmology, China-Japan Friendship Hospital)