What is dangerous for night blindness, snow and cortical

There are different types of vision disorders, when a person ceases to see at dusk, in bright light, or just suddenly there comes complete blindness. Let's see what specific types of blindness exist, what they are related to, and what help can be provided.

Chicken blindness

If a person has a narrowed vision with the onset of darkness, then he is diagnosed with night blindness. The name of the disease is due to the fact that the hens at twilight and darkness lose the ability to see well. And there is nothing to do with chickens anymore.

Before the revolution in Russia, this disease was widespread among the rural population, especially exacerbated in the spring.

The mechanism of constriction of twilight vision in general terms is this: in normal human sensitivity to light in the dark increases sharply. The ability for such a dark adaptation is due to the concentration of rhodopsin, which contains vitamin A. If the vitamin in the body is not enough, then rhodopsin is released in small quantities, and the eye loses its ability to respond adequately to the onset of darkness.

Therefore, night blindness is associated with a significant shortage or overabundance in the body of vitamins A and PP, as well as certain B vitamins. Twilight vision is the earliest sign of significant disorders in the body.

By the way, scientists have found out that children can be afraid of darkness not because of terrible fairy tales or their fantasies. These fears can be directly related to the manifestations of their night blindness and lack of necessary vitamins.

There are other causes of the disease:

- diabetes;

- cataract;

- Retinal diseases.

But if these reasons are excluded, but it is necessary to replenish the balance of vitamins in the body so that the night blindness is gone. To do this, doctors prescribe large doses of vitamin A concomitantly with riboflavin and vitamin B6. The course of treatment is from several weeks to a month, depending on the severity of the symptoms.

It must be remembered that in large doses vitamin A becomes toxic, so it is impossible to be too zealous or self-medicate in this case.

For the prevention should regularly eat carrots and pumpkin, and in the season - apricots and tomatoes.

Snow Blindness

This disease manifests itself in very bright sunlight, especially when the sun reflects off the surface of the snow. Then the person appears in the eyes, tears flow, there is photophobia. The retina in such people is too sensitive to ultraviolet light, which leads to allergies to bright light.

Why does such a reaction occur in winter? The fact is that the ultraviolet, reflected from the snow, has a more powerful effect. This can lead to a retina burn and loss of vision for several days. With an easier course of the disease, redness and inflammation of the eyes occur, the pigmentation around them changes.

For the prevention of snow blindness, it is recommended to wear sunglasses when it is necessary to go out on a bright sun on a snowy winter day. That's why mountaineers and alpinists necessarily protect their eyes.

Cortical blindness

This disease is manifested by a sudden total loss of vision. The cause of cortical blindness is a violation of blood circulation in the cortical lobes of the brain. This disease is not independent, but arises as a consequence of atherosclerosis and hypertension. Poisoning the body with lead or carbon monoxide can also lead to cortical blindness.

The appearance of cortical blindness is often preceded by a period of partial loss of visual fields.

Cortical blindness refers to neurological types of visual impairment, so at the first symptoms it is necessary to urgently seek help not only from the oculist, but also from the neurologist.