What is night blindness?

I believe everyone has heard of the disease called night blindness. The main symptom of this disease is the inability to see when going out at night. Therefore, it is recommended that friends with night blindness should pay more attention when going out at night to better ensure your safety. Night blindness is mainly caused by a lack of vitamin A, so friends who overuse their eyes should pay more attention to eating foods containing vitamin A, which can help us inhibit vision loss.

In fact, there are many reasons for night blindness, but the main reason is the lack of vitamin A in our body. For some friends who overuse their eyes, their bodies consume more vitamin A. If they do not supplement it in time, it is likely to cause night blindness.

Night blindness refers to the inability to see or unclear vision in the dark during the day, which is mainly caused by weak spleen and stomach and weak fire in the life gate. Night blindness caused by weak spleen and stomach is more common in children, with symptoms such as big belly, sallow face, thin body, sparse hair, normal vision during the day but inability to see at night or in dim light. If the fire of Mingmen is weak, the patient will suffer from night blindness at first, and then the vision will gradually deteriorate, accompanied by symptoms such as dizziness, weakness, fear of cold, loss of appetite, spermatorrhea, impotence, white tongue coating, and weak and thin tongue.

Vitamin A deficiency can cause night blindness:

There are cone cells and slender rod cells in the retina of the human fundus, and both types of cells contain the same light-sensitive substance, rhodopsin. Vegetables and fruits containing vitamin A can prevent night blindness. Cone cells are used to see objects during the day, and slender rod cells are used to see objects at night. The photosensitive substances in these two types of cells are actually proteins involving vitamin A (retinol). When exposed to light, the protein undergoes structural changes, which in turn triggers nerve impulses to be transmitted to the brain to form images, while rhodopsin itself "fades".

If you enter a dark place at this time, the eyes will be insensitive to light due to the disappearance of rhodopsin, and you will not be able to see objects. Under normal circumstances, the human body has enough vitamin A, which, under the action of retinal and liver enzymes, promotes the regeneration of rhodopsin, restores sensitivity to light, and enables people to see the shape and color of objects in the dark. If the body lacks vitamin A, the regeneration of rhodopsin will be not only slow but also incomplete. When people enter a dark place from a bright place, they will not be able to see objects for a long time. We call this phenomenon a decreased dark adaptation ability (you can measure your vitamin A level based on your dark adaptation ability). It is often caused by a severe lack of vitamin A and the inability to regenerate rhodopsin, which is what people often call "night blindness."

Some people describe the human eye as a sophisticated camera, and the retina is like the film of the camera, which develops the information and light received by the eye and finally forms vision in the brain. Vitamin A is the photosensitive substance in the film. When vitamin A is deficient, photos cannot be sensitive to light and vision cannot be produced, especially at night. Since more vitamin A is consumed at night than during the day, it is called night blindness.

After reading this article, you should have a certain understanding of what night blindness is. If you want to know more about night blindness, it is recommended that you read relevant methods online, which will help you understand night blindness. For the health of our family, I hope everyone can learn more medical knowledge so that we can better prevent the occurrence of diseases.