Night blindness is the difficulty of seeing in dimly lit places, a vision disorder called nyctalopia. Its main causes are: retinitis pigmentosa, lack of vitamin A, cataract and myopia. There are also cases where night blindness accompanies the person from birth (congenital night blindness).
Night blindness is caused by changes in the rods, which are the nerve cells used by the retina to pick up light and shades of white, black, and gray. If there is any anomaly or injury to these cells, partial loss of vision may occur in low light situations.
The main symptom of night blindness is difficulty in seeing at night or in poorly lit places. In addition, for people with the disorder it is also difficult to see things when they move from a place with more light to a less illuminated one, or when they leave the penumbra to an area with enough luminosity.
The main cause of night blindness is retinitis pigmentosa, a disease of genetic origin that makes it impossible for rods to react to light. There are cases where even daytime vision is affected.
THE congenital night blindness is hereditary and is linked to the X chromosome. Individuals with this disorder have difficulty seeing at night from birth. However, the nocturnal vision of these patients does not worsen over time, unlike what usually happens in cases of nicotopia.
Already the night blindness caused by vitamin A deficiency particularly affects children and the elderly. Without the vitamin, the region of the retina responsible for night vision ceases to function, since the nutrient is essential to regenerate a substance present in rods.
At cataract, in addition to night blindness, there may be partial or total loss of vision due to opacity of the lens. As a result, the vision becomes blurry, with blurred and opaque images, and a whitening may be noticed in the center of the eye.
The treatment of night blindness depends on its cause. It is often possible to treat the disorder with the use of glasses or supplementation with vitamin A. Cases of cataract can only be resolved with surgery.
Learn more at: Does night blindness have a cure?
Night blindness should be evaluated by an ophthalmologist, who will identify the cause and indicate the most appropriate treatment in each case.
