The disease hemeralopia, popularly known as night blindness, is a violation of the mechanism of adaptation of vision to low light conditions. The main feature of the disease is that a person sees very poorly in absolute darkness and during twilight. Due to the disease, spatial orientation worsens, visual fields are narrowed, and the perception of shades of yellow and blue is reduced.
Why is it becoming invisible in the darkness?
Rod photoreceptors located on the retina of the eye are responsible for the function of vision during a decrease in the lighting of the space. Rhodopsin, which is a pigment of rods, breaks down when exposed to light. For its regeneration to take place, some time must pass. In addition, this process takes place with the participation of vitamin A. With a lack of rhodopsin or structural changes in rod photoreceptors, chicken blindness occurs.
Types of disease
There are three types of pathology:
- Congenital night blindness. This is a hereditary pathology that manifests itself in children and adolescents. She is characterized by a steady decrease in vision in the twilight time of the day and a significantly reduced adaptation to the dark.
- Essential night blindness. A disease that is caused by a lack of vitamin A in the body. It may also be associated with impaired retinol metabolism. As a rule, liver disease, alcohol dependence, starvation, neurasthenia, malaria, etc. can contribute to the onset of this condition. Such blind blindness is most often temporary.
- Symptomatic hemeralopia. This type of disease can occur with certain types of degenerative conditions of the retina. These include tapetoretinal dystrophy. Also, the development of the disease can be a consequence of inflammatory processes that occur in the retina and vascular system of the eye (chorioretinitis), glaucoma, optic atrophy, high myopia.
Of all the above varieties of night blindness, the most common type is essential hemeralopia. It doesn’t matter what etiology of the disease, in all cases the cause of the pathology is the same - the processes of rhodopsin regeneration, the pigment of rod photoreceptors, are disturbed in the retina of the eye.
Symptomatology
An exacerbation of the disease most often occurs in the spring, since at this time there is a significant lack of vitamin. Night blindness can also develop in completely healthy people who do not have any pathologies and eye diseases. A problem may arise if a person’s activity is related to working on a computer, while the conditions for normal lighting of a workplace are not met. Lack of light leads to irritation of nerve endings and the symptoms typical of night blindness. To avoid the disease, it is recommended that after each working hour for the PC take a 30-minute break so that the eyes rest.
The main symptoms of the disease are the deterioration of vision in the dark, as well as a decrease in the sensitivity of the retina to bright light.
It happens that with night blindness there is a decrease in color perception. Also, spots may appear in the patient's field of vision when moving from a dark space to a bright one.
The Importance of Vitamin A
As we explained above, the main cause of night blindness is a lack of retinol (vitamin A). What is this substance and what role does it play in the normal functioning of the vision system?
Once in the human body, vitamin A is involved in metabolic processes and the restoration of rhodopsin, the visual pigment that is an integral part of rod photoreceptors. With any violations of the formation of rhodopsin, problems arise with the perception of light.
The eye retina consists of two types of cells: cones and rods. Rod-shaped photoreceptors provide normal visibility in low light. But visual acuity and color determination are the functions of cones.
The formation of rods, which include rhodopsin, occurs directly with the participation of retinol. Without it, pigment production is impossible. Light entering the retina leads to the breakdown of rhodopsin, and if the body experiences an acute deficiency of retinol, night blindness develops. Vitamin A helps to regenerate pigment, and if it is not enough, it will take a long time to recover.
First of all, you need to understand, which led to a decrease in the level of retinol. The therapist can help with this. Vitamin deficiencies can be compensated for by food. Most of it is found in carrots, green onions and butter.
There are times when vitamin A is not absorbed by the body. There can be several explanations for this:
- alcoholism;
- endocrine system diseases;
- problems with the digestive tract (liver, stomach, intestines).
The patient may be prescribed a diet and a complex of vitamins. It is recommended to eat green onions, carrots and butter. It is also worth including in the diet liver, milk, vegetables and orange fruits, spinach leaves.
Which doctor should I go to?
If there are problems of visibility in low light, this is an occasion to go to the doctor. Since the symptoms relate to the organs of vision, consultation with an ophthalmologist is necessary. After the diagnosis, the doctor will determine the cause of the disease and make a diagnosis.
Do not ignore the symptoms. Night blindness is a rather serious pathology. It can be secondary in nature and be the result of any serious eye disease. Quite often, night blindness develops with retinal dystrophy. If the problem is identified in a timely manner and treatment is started, this will save vision and prevent complete blindness.
Diagnostics
First of all, the doctor will carefully listen to all the patient's complaints and conduct an examination of the organs of vision. Then, to determine the degree of development of pathology, diagnostic studies are carried out:
- Adaptometry. Helps assess light perception. A flash of light is produced in the direction of the eye, after which it is determined for how long the vision will restore to its original state.
- Perimetry. Used to assess the radius of the field of view.
- Electroretinography. This is a more modern diagnostic method that allows you to identify various abnormal conditions of the retina. A flash of light is directed into the patient’s eye, then the specialist determines the electrical potential of the visual system in response to too bright radiation.
- Electrooculography. This is a study of the eye muscles and surface of the retina during the movement of the eyeball.
If the diagnosis of "night blindness" has been confirmed, treatment should be started immediately. Timely therapy gives excellent results, so you can save vision and restore the function of visibility in the dark.
Treatment of ailment
It should be noted that not all types of night blindness are treatable. Therapy will be ineffective in a congenital form of the disease. In order for a person to be able to see normally at dusk, it is necessary to eliminate the cause that prevents this. However, it is impossible to fix the problem caused by genetic changes.
The main objective of the treatment course is to restore the balance of retinol in the body. Therefore, you need a diet that includes foods high in vitamin A. This category includes cabbage, carrots, fruit and berry juices, fish liver, butter, cheese, peaches, berries, herbs and eggs.
Also, vision correction can be carried out using special lenses. However, they only slightly improve visual acuity in the dark.
Surgical treatment for night blindness is used if the disease is caused by a high degree of myopia.
Even if the disease is hereditary, a patient with such a diagnosis should regularly use foods containing vitamin A.
Prevention
The main method of prevention is diet therapy.
Important to remember! That in the dark, in poor lighting, you can not read books or work on the computer. Failure to comply with these rules can lead to the development of pathologies such as night blindness.
Traditional medicine recipes
As a disease prevention, you can use the advice of traditional medicine:
- In addition to following a diet, you need to eat fish oil three times a day. Now it can be purchased in pharmacies in the form of capsules.
- You can improve visual acuity with a decoction of millet. To do this, take 2 liters of water and 200 g of cereal. You need to cook until millet is fully cooked.
- Well established broth from carrots and milk. In 1 liter of milk, add grated carrots in the amount of 3 tbsp. l and cook until fully cooked. To drink at night approximately 75 ml.
Can I drive in night blindness?
The vision of a person suffering from hemeralopia deteriorates significantly with the onset of darkness. At this time, not only light perception decreases, but also the field of view narrows. Because of this, a person does not see what is happening on the sides. He is not able to adequately assess the situation and make the right decision, moving along the highway. And such mistakes can cost not only health, but also life.
With hemeralopia, adaptation to the dark often occurs. It is difficult for the eyes to get used to the changes in light during the transitions from well-lit areas to darker ones. And if oncoming cars will shine headlights, the driver having such pathology will be blinded in the literal sense of the word. Therefore, the conclusion is obvious - to drive a person with a diagnosis of "night blindness" (especially in the evening) is strictly prohibited. Such a driver poses a threat not only to himself, but also to other participants in traffic.