Snow blindness is a kind of temporary blindness caused by strong light stimulation to the retina of the eye. For many explorers who like to explore the ice and snow world, it is a very common phenomenon, so what is the cause of snow blindness?
Causes of snow blindness
There are two different views on the causes of snow blindness, one is that the snow blindness is caused by the light reflected on the snow, the other is that there is nothing in the eye and there is no reference, which leads to the temporary blindness of the eye.
1. The first one comes from traditional medicine. They believe that snow blindness is caused by the more intense reflection of sunlight on the plane formed by snow, which produces a strong stimulus to human eyes. Because in snowy days, the ground is covered by white snow, and the relatively strong sunlight shines on the snow. Because the absorption capacity of white snow to light is very low, at this time, the reflection of snow to ultraviolet can be increased by 5% - 6%. The light reflected by white snow shines on the eyes, and a large amount of ultraviolet is absorbed by the cornea and conjunctiva of the eyes. It will cause eye damage similar to electro-optic ophthalmia, causing retina to be strongly stimulated and damaged, resulting in photophobia, tears, tingling and even temporary blurring of vision (snow blindness usually occurs 6-8 hours after snow radiation, which can occur in one eye or both eyes at the same time). Because of the strong reflection of snow sunlight, looking directly at the snow is like looking directly at the sun. In particular, the ultraviolet light converges on the macular area of the retina through snow reflection, which will cause greater damage to the macula, which is equivalent to the optical center of the human eye, and is very important for the generation of vision. Once the macula is damaged, it can directly lead to the decline of vision. On the other hand, on the vast snowfield, the surface of snow in some places is slightly concave, like the concave of a searchlight. In such a place, white light may appear. The snow surface with white light is more concentrated and stronger than the sunlight reflected by ordinary snow surface. In general, the snow surface does not directly reflect the sun's light into the eyes like a mirror, but stimulates the eyes through the scattering of the snow surface. When the human eye is stimulated by the scattered light for a long time, it will also suffer from snow blindness.
2. Another view is that the cause of snow blindness is not the dazzling reflection of the snow, but its emptiness. According to a recent study by the U.S. Army, human eyes are always tirelessly exploring the world, from one place to another. If a continuous search fails to find any landing point, it will be blind due to tension. "They think that although the name of snow blindness may seem to be related to the snow environment, it is not the case in fact. Any environment that produces strong light conditions may cause snow blindness. As Dr. Sha Xiangyin once pointed out, snow blindness may be caused by the wide sea, the desolate desert, watching the total solar eclipse, or even the large area of glass curtain wall in the city.
The harm of snow blindness
As an acute ophthalmopathy, snow blindness is very serious to the visual nerve damage. After being reflected by strong sunlight, ultraviolet light in the sunlight causes serious damage to the cornea and conjunctival epithelium, which makes the eyes appear photophobia, tears, tingling and even blurry for a short time. It is characterized by red eyelid, congestion and edema of conjunctiva, intense foreign body sensation and pain. The symptoms are the most serious within 1-2 hours after the onset of the disease. Usually, as long as good treatment and rest, generally a week can be cured. If the pain of both eyes is not serious, and there is no other obvious performance, let both eyes rest properly and then they can recover by themselves.
But for the alpine skiers who have been in the alpine environment for a long time, the harm of snow blindness is more serious. Although the acute damage to the eyes caused by ultraviolet is easy to recover and not easy to leave sequelae, if the chronic damage accumulates to a certain extent, it will cause serious damage to the eyes, or even can not recover. Therefore, people who have been snow blind, once they do not pay attention to get snow blindness in the next time, then the situation will be more serious, the light vision is weak.
Therefore, people who have been snow blind will be snow blind again. Once again, snow blindness symptoms will be more serious, causing long-term eye disease, and even permanent blindness.
Self rescue measures
Treatment for snow blindness includes pain relief and prevention of re injury. Therefore, it is necessary to leave the light source and live in the dark room immediately after being reflected by the strong light of the snow field; it is necessary to apply cold compress locally in time and close the eyes for rest.
After being far away from the source of irradiation, the injured athlete's eyes should be cleaned with clean cold water or professional eye drops, then the ointment should be applied, and finally the eyes should be lightly covered with eye mask or other items (such as clean handkerchief, clean gauze, etc.). Rest as much as you can and avoid using your eyes. Generally, the symptoms of snow blindness can be recovered in three days within 24 hours, and the symptoms with a little severe usually need five to seven days to be eliminated.
In the process of rest and recovery, fresh human milk or fresh milk can also be used for eye drops, 5-6 drops at a time and every 3-5 minutes. The milk used should be boiled and cooled thoroughly before use. You can also wash your eyes with liquid medicine, go to the dark place or cover your eyes with an eye mask and chill them with a cold towel. This can speed up the recovery process of athletes. It should be noted that in this process, the use of eyes must be reduced and rest as much as possible. Don't apply hot. High temperature will aggravate the pain. During recovery, eye protection must be strengthened to prevent continuous or re injury. After simple treatment, goggles should be put on immediately. People who wear contact lenses must take them off to reduce the chance of corneal irritation and infection. At the same time, eyes must be protected from strong light stimulation. Remind snow blind people not to rub their eyes and try to rest. In order to avoid the action of eyelids disturbing the eyes, it is advisable to cover the eyes with sterilized cloth and pads, and check the sensitivity of the eyes to light every half day. When the eyes are no longer extremely photophobic, the dressing can be removed. However, protective sunglasses should always be worn.
If snow blindness is more serious or more serious due to their own treatment errors, they should go to the hospital in time for treatment.
After the clinical examination, take the medicine on time according to the prescription prescribed by the doctor. Generally, it is eye medical liquid, such as Coptis liquid or ximycin eye liquid, hydrocortisone eye drops alternately, which can quickly control symptoms and get treatment. However, those who are more serious need to be treated with corresponding prescriptions for a long time.
2. Massage therapy
The patient's hands were washed and dried, the palms were closed and rubbed with heat, the eyes were pressed flat immediately, and the eyes were moved clockwise once a day in the morning, middle and evening, 5-10 minutes each time. You can also choose zanzhu, sishukong, Sibai, sun, Qingming and other acupoints. Massage each acupoint 30 times, three times a day.
Wear glasses to protect eyes, wear eye mask to protect eyes when going out, and take vitamin B2, e, a pill and other drugs for treatment.