Chicken blindness is the popular name of the disease, in medicine known as hemeralopia (impaired vision adaptation to reduced illumination). A person suffering from these diseases, very poorly sees in the twilight and at night, but in daylight, his visual acuity persists.
It would seem - where are the chickens? The fact is that the ability of the human, and of any other eye, to adapt to conditions with different illumination depends on the photosensitive elements of the retina: rods and cones. The cones are responsible for day vision, and the sticks, which have a high photosensitivity - for the night. In chickens, sticks in the retina are almost absent, and therefore with sunset they actually become blind. Because of this feature, a disease in which people are weakened by night vision, and was called night blindness.
Causes of night blindness
The disease develops due to a violation of the ratio between the number of cones and rods in the human eye, the reduction in the number of rods or structural disorders of their structure, as well as due to a lack or disruption in the exchange of the visual pigment of rhodopsin, which is contained in the sticks.
It is customary to distinguish three types of night blindness:
- congenital;
- Essential;
- symptomatic.
The most common is essential night blindness. The disease can develop against the backdrop of malnutrition, due to a lack of vitamins, in the first place - vitamin A. In addition, it can be caused by anemia, liver disease, general exhaustion of the body, exposure to various toxins.
Symptomatic night blindness develops against a background of eye diseases, such as glaucoma, retinitis pigmentosa, high degree myopia.
Congenital night blindness is most often caused by some hereditary diseases, in particular, hereditary pigment retinitis or Asher syndrome.
Symptoms of night blindness
With chicken blindness, eyesight deteriorates sharply in low light conditions. Its sharpness decreases, objects can look fuzzy, blurred, the field of view narrows, color perception is violated. Often the correct perception of blue color suffers, or there is no color vision at all in the twilight and at night. It is also possible the appearance before the eyes of dark spots during the transition from the illuminated room to the dark and back.
How to treat night blindness?
It should be noted that the treatment of night blindness depends on its type and the factors that caused it.
The disease of an essential type lends itself most easily to treatment. Since most often this type of night blindness is caused by a lack of vitamin A, then to eliminate the disease it is enough to drink a course of vitamins.
In case the lack of vitamin A has arisen because of the intake of drugs that are its antagonist (for example, quinine), the medication should be immediately canceled and the course of intake of vitamins should be immediately performed. When night blindness is caused by a liver disease, infection and the like, the primary disease is treated primarily.
The only prevention of this type of disease is proper nutrition. You should eat carrots, cabbage, citrus fruits, fresh juices, liver of fish and mammals.
With symptomatic hemorrhagia, first treat the underlying eye disease. This can be the selection of correct glasses and the use of firming drugs for myopia. Taking medications and, if necessary, surgery for cataracts or glaucoma.
The congenital form of night blindness does not respond to treatment, and there is a constant decrease in twilight vision.