3D movies are three-dimensional movies, which first appeared in 1953 (Hollywood, of course). When shooting a 3D movie, two cameras are needed to imitate the human eye angle of view. At the same time, two projectors are used to shoot and play simultaneously. Many parents like to take their children to see 3D movies, however, children are not suitable. Try not to watch 3D movies for children under 12 years old. Here are seven reasons!

Seven reasons for not watching 3D movies under 12

1. 3D imitates human’s binocular vision

Watching “Avatar”, “Pirates of the Caribbean”, “Transformers 3” and other 3D blockbusters not only makes people feel the scenery coming, but also makes them feel as if they have entered the depth of the screen and have a strong sense of immersiveness.

Why is it so wonderful?

D is the prefix of dimension in English. 3D refers to three-dimensional space. In the world, 3D films are used to represent three-dimensional films.

In 1839, British scientist winterston discovered a wonderful phenomenon. The distance between people’s eyes is about 5cm. When they look at objects, they have different angles, that is, there are two angles of view. This subtle angle difference, transmitted to the brain through the retina, can distinguish the front and back of the scene, and then produce a strong sense of three-dimensional.

This is the secret of “three-dimensional” – polarized light principle.

3-D movies use “polarized light” cleverly. It uses two film cameras which are placed side by side to represent the left and right eyes of a person, and simultaneously shoots two films with slight horizontal parallax.

During the screening, the two films are loaded into the left and right movie projectors respectively. When the picture is put on the screen, it will form a double image with fine left and right.

When the audience wears unique 3D glasses (polarized glasses), the left eye can only see the left image, the right eye can only see the right image. Through the binocular convergence function, the left and right images are superimposed on the retina, and the brain nerves produce three-dimensional visual effects, so as to show a continuous three-dimensional picture, making people feel the magic illusion of being in the scene.

2. Frequent focusing makes eyes tired

A friend asked: my eyes shed a lot of tears after watching the whole avatar. It’s really painful. Is there anyone like me?

Researchers in the United States conducted experiments in two studios, and came to the same conclusion: 3D movies and TV will promote the brain to have convergence regulation differences, and make a large number of people appear fatigue, discomfort, eye tension, headache and other symptoms.

What is convergence? When the viewer looks directly at a closer object or scene, his eyes will slightly turn inward, so that the visual focus is focused on the object to be viewed; while when he gazes at a distance, the visual axis of his eyes is parallel. This phenomenon is called convergence.

What is regulation? When looking at different objects, the muscles in the eyes will automatically adjust the optical focus to focus on something, which is called adjustment.

Under normal circumstances, the eye’s radiation and regulation are coordinated with each other, and the brain can easily couple these information together. However, the world seen through 3D glasses is divided into two sides, that is, the image of the scene in front of or behind the screen is sent to the left and right eyes respectively.

At this time, the eyes should focus on the scene in front of the screen, or the scene behind the screen (convergence). At the same time, they have to adjust the screen visually. The coordination of human convergence and adjustment is disrupted.

When the human body watches 3D movies for a long time, the brain is forced to decouple the information transmitted to the brain by “radiation regulation” in the uncoordinated situation, which will lead to visual fatigue, blurred vision, discomfort, headache and other symptoms.

3. Create a sense of motion and make people dizzy

A female college student said: when watching avatar, I felt OK at first. After more than ten minutes, I began to feel sick. I felt dizzy, chest tightness, cold sweat and vomiting. I couldn’t stand it but to come out. It’s only more than half an hour since I saw it. I’m so upset about Mimi!

Is her dizziness just a case in point? No! Now there is a hot topic on the Internet – “3D vertigo”, which is the problem of “three dishes of dizziness” for the audience of avatar.

Look at 3D, why do you feel dizzy?

The 3D movie picture is lifelike, lets you have the immersive feeling. Moreover, the visual angle of the screen changes frequently, and people’s eyes will constantly adjust to adapt to the content on the screen, and constantly convey the information of “they are really moving” to the brain.

You don’t actually exercise in your seat. “Movement” is only the wrong judgment made by the visual center, so the brain can not receive the signal of muscle movement, so the brain has a “perception error” contradiction, resulting in the confusion of the nerve center.

The center tries to get rid of this dilemma, sends out strong vertigo instructions, and hopes to readjust the movement state of the body. People may have dizziness, nausea and other uncomfortable symptoms.

Moreover, in 3D movies, there are not only the real focus pictures in front of or behind the screen, but also the virtual focus scenery pictures with rich elements, such as the leaves in the virtual focus of the distant view, which are part of many elements. When watching 3D movies, because these elements will refocus the eyeball, and repeatedly fail to focus, it is also easy to produce 3D vertigo.

Therefore, people with a history of severe vertigo, carsickness and seasickness, epilepsy, and those with a relatively easy sense of balance of the vestibular organ are not suitable for 3D movies.

4. Strong stimulation can cause glaucoma

Experts remind that those with high intraocular pressure, those with “shallow anterior chamber, narrow angle” glaucoma high-risk groups, trying 3D visual stimulation, is a dangerous behavior.

The anterior chamber is the space behind the cornea, before the iris and pupil; the posterior chamber is behind the iris, pupil and before the lens.

The front and back rooms are filled with transparent liquid, which is called room water. The aqueous humor circulates continuously in the anterior and posterior chamber, and generates and discharges continuously to maintain the intraocular pressure at a stable level.

The eyeball is a closed structure. If the angle of the aqueous humor is blocked, the aqueous humor is blocked and the intraocular pressure is increased, which causes too much pressure in the eyeball, the optic nerve will be damaged. Glaucoma is a kind of optic nerve damage.

When a Taiwanese watched a 3D film, it caused acute glaucoma. The intraocular pressure soared from below 20 to 69. He was in emergency. Why?

Because when people are excited, it is easy to cause pupil enlargement and intraocular pressure rise. In clinic, we often meet some football fans who are too excited to cause acute glaucoma. However, the vivid images and shocking scenes of 3D movies can easily make people excited.

Those who have high risk factors of glaucoma (such as “shallow anterior chamber, narrow chamber angle”) are more likely to lead to higher intraocular pressure; in addition, 3D images are more eye consuming, and many factors are added together, which will lead to the onset of acute glaucoma.

5. Flash induced photosensitive epilepsy

In April 2010, Samsung Electronics published a low-key report on its Australian website, warning of photosensitive epilepsy and other health risks. Sony and Panasonic have also raised similar warnings for consumers using 3D technology products.

Photosensitive epilepsy is a kind of brain spasm response induced by flash stimulation.

When the intense flash stimulation on the screen is received by the retinal nerve cells and transmitted to the brain, it will cause abnormal discharge of neurons and disturb the normal function of the nerve center, which will lead to epilepsy.

Some mental health experts say that light sensitive epilepsy caused by long-term exposure to TV or computer screens has been increasing in recent years.

For example, there is a programmer in Nanjing who suddenly appears pale, unconscious and foaming at the mouth because he is in a hurry for the project in front of the computer day and night. He was found to have photosensitive epilepsy.

For example, a sophomore who played online games for 10 hours in summer vacation suddenly had blurred vision and convulsions. According to the doctor’s diagnosis, his disease is also photosensitive epilepsy.

Although there are no examples of photosensitive epilepsy caused by watching three-D movies, the plants on Pandora in Avatar are bright, the huge and gentle herbivores, the small and fierce carnivores, and the flying mounts of the Na’vi people all stimulate the audience’s eyes and mind. For epileptics, this kind of stimulation is likely to cause seizures 。

The health risk report lists possible physical discomfort, as well as directional disorders, the most serious of which is stroke.

6. Affect the normal development of children’s eyes

“Toy Story 3”, “Shrek 4” and other 3D animation have attracted many children’s attention. What are the potential effects of three D films on children?

(1) eyes

Watching 3D film may affect the normal development of eyes.

The development period of eye structure: from birth to 3 years old.

People’s stereopsis has not developed well before the age of 3, and only after the age of 5 can it develop completely.

The developmental stage of eye function: 4-13 years old.

Under the influence of various internal and external factors, the growth and development of children’s eyes have great variability, and the most important of these changes is the change of refractive system, which results in the plasticity of the eyes.

If children use different images of left and right eyes to achieve 3D effects, let the eyes constantly move the muscles of the eyes, tense, and constantly adjust their lenses to change the focal length, there is a potential impact on their eye development, which is likely to cause strabismus, amblyopia, etc.

(2) Psychology

Some studies have pointed out that excessive acoustooptic stimulation can cause adverse reactions in children.

“This is not Po panda! Dad, let’s go home quickly! ” A kid who just went to kindergarten is watching videos at home. He likes panda a Bao. But when his father took him to see the 3D version of Kung Fu Panda 2, he couldn’t sit still just after the opening.

An overseas electronic art researcher filmed and recorded the faces of four or five-year-old children staring at the TV, and found that within 10 minutes, their faces became almost “dementia”.

“Fast switching lenses can easily cause excessive information input to children, forcing the brain to ‘overload’,” the researchers explained. For children, the audio-visual stimulation of information explosion is like dyeing white paper into black in an instant. “

(3) attention

Education experts point out that children’s “attention” characteristics are not suitable for watching 3D movies for a long time.

Children’s attention varies with age. In general, for children aged 5-6, the time of concentration is 10 minutes; for children aged 7-8, the time of concentration is 15-20 minutes; for pupils over 8, the time of concentration is 20-30 minutes; for junior and senior high school students, the time of concentration is 30-45 minutes.

If you take a younger child to watch a movie for more than 100 minutes, it will cause the child’s restlessness.

7. It’s better to take a 30 minute break

What should I do if I want to feel the trend of the times and stay away from health risks?

If the eyes are strong or weak, the image will be distorted, unable to be combined, and will cause discomfort. Therefore, please wear corrective glasses to watch the myopia, hyperopia and astigmatism.

If there are hidden dangers in the eyes, which make the eyes unable to cooperate effectively and can not see the 3D effect, there is no need to spend money to see 3D.

People with epilepsy, heart disease and other diseases had better not watch them, so as to avoid aggravating the disease.

People over 35 years old who have a family history of glaucoma should rest for 5-10 minutes in the light environment every half an hour.

If you feel headache or nausea or blurred vision when watching 3D movies, or there is a colorful rainbow circle around when watching lights, you can’t get rid of it even if you knead it by hand. You should be alert to the acute attack of glaucoma and seek medical treatment in time.

For people with healthy eyes, it’s better to close their eyes every once in a while to relax them. It is recommended that you take off your 3D glasses after 15-20 minutes of watching, and close your eyes and rest for 1-5 minutes. It’s better to have a rest after 30 minutes.

The position should not be too close to the screen. It is best that the seat is 15-20 meters away from the screen. Be sure to sit up straight and face the TV screen, so that your eyes will not easily feel tired.

What about children?

Italy’s top health care Commission has issued a notice banning children under the age of six from watching 3D films, while some experts believe that the safe age limit is 8 years old, or even 10 or 12 years old.

Baibai safety net suggests that babies under 12 years old should not look. First, it is to protect their eyes. Second, it is because babies who are too young can not understand it. They also look for nothing. If you are interested in children’s home electric shock prevention knowledge, please go to this safety net to find relevant information.