Hemeralopia disease, 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. Because of the disease, orientation in space worsens, fields of vision narrow, the perception of shades of yellow and blue is reduced.
Why is it becoming invisible in the dark?
Rod photoreceptors located on the retina of the eye are responsible for the function of vision during a decrease in the illumination of space. Rhodopsin, which is the pigment of the rods, breaks down in the process of exposure to light. It takes some time for it to regenerate. In addition, this process takes place with the participation of vitamin A. With a lack of rhodopsin or structural changes in rod photoreceptors, night blindness occurs.
Disease types
There are three types of pathology:
- Congenital night blindness. This is a pathology of a hereditary nature, which manifests itself in children and adolescents. She is characterized by a steady decrease in vision at dusk and a significantly reduced adaptation to the dark.
- Essential night blindness. A disease caused by a lack of vitamin A in the body. It may also be associated with impaired retinol metabolism. As a rule, liver diseases, alcohol dependence, starvation, neurasthenia, malaria, etc. can contribute to the occurrence of such a condition. This kind of night blindness is most often a temporary phenomenon.
- Symptomatic hemeralopia. This type of disease can occur with certain types of dystrophic conditions of the retina. This includes tapetoretinal dystrophy. Also, the development of the disease can be a consequence of inflammatory processes occurring in the retina and vascular system of the eye (chorioretinitis), glaucoma, optic nerve atrophy, high myopia.
Of all the above varieties of night blindness, the most common type is essential hemeralopia. It does not matter what the etiology of the disease is, in all cases the cause of the pathology is the same - in the retina of the eye, the processes of regeneration of rhodopsin, the pigment of rod photoreceptors, are disrupted.
Symptomatics
Exacerbation of the disease most often occurs in the spring, as at this time there is a significant lack of vitamin. Night blindness can also develop in perfectly he althy people who do nothave 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 workplace lighting are not met. Lack of light leads to irritation of nerve endings and symptoms characteristic of night blindness. To avoid illness, it is recommended to take a 30-minute break after each working hour at the PC in order to rest the eyes.
The main symptoms of the disease are 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 light one.
The Importance of Vitamin A
As we found out 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 visual system?
Once in the human body, vitamin A is involved in metabolic processes and the restoration of rhodopsin, a 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 definition are the functions of cones.
Formationrods, which include rhodopsin, occurs directly with the participation of retinol. Without it, pigment production is impossible. Light, falling on 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 figure out what led to a decrease in retinol levels. A therapist can help with this. Vitamin deficiency can be compensated for with 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 may be several explanations for this:
- alcoholism;
- diseases of the endocrine system;
- problems with the digestive tract (liver, stomach, intestines).
The patient can be prescribed a diet and a complex of vitamins. It is recommended to eat green onions, carrots and butter. It is also worth including liver, milk, orange-colored vegetables and fruits, spinach leaves in the diet.
Which doctor should I contact?
If you have problems seeing in low light, this is a reason to go to the doctor. Since the symptoms relate to the organs of vision, an ophthalmologist's consultation is necessary. After the diagnosis, the doctor will determine the cause of the development of the disease and make a diagnosis.
Don't ignore the symptoms. Night blindness is a rather serious pathology. It can be secondary in nature and be a consequenceany 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.
Diagnosis
First of all, the doctor will carefully listen to all the complaints of the patient and examine the organs of vision. Then, to determine the degree of development of the pathology, diagnostic studies are carried out:
- Adaptometry. Helps to evaluate light perception. A flash of light is produced in the direction of the eye, after which it is determined over what period of time the vision will be restored to its original state.
- Perimetry. Used to evaluate 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 the surface of the retina during the movement of the eyeball.
If the diagnosis of "night blindness" is confirmed, treatment should be started immediately. Timely therapy gives excellent results, thanks to which it is possible to preserve vision and restore visibility functions in the dark.
Treatment of disease
It should be noted that not all types of night blindness are treatable. Therapy willineffective in the congenital form of the disease. In order for a person to see normally at dusk, it is necessary to eliminate the cause that prevents this. However, there is no way to fix the problem caused by genetic changes.
The main task 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 marginally improve visual acuity at night.
The surgical treatment of night blindness is used if the disease is caused by high myopia.
Even if the disease is hereditary, a patient with this diagnosis should regularly consume 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 at a computer. Failure to follow these rules can lead to the development of a pathology such as night blindness.
Recipes of traditional medicine
As a preventive measure, you can use the advice of traditional medicine:
- In addition to dieting, you need to consume fish oil three times a day. Now it can be purchased in pharmacies in the form of capsules.
- Improvevisual acuity can be done with a decoction of millet. To do this, take 2 liters of water and 200 g of cereals. You need to cook until the millet is fully cooked.
- A decoction of carrots and milk has proven itself well. In 1 liter of milk add grated carrots in the amount of 3 tbsp. l. and cook until fully cooked. Drink at night about 75 ml.
Can I drive with night blindness?
The vision of a person suffering from hemeralopia deteriorates significantly at nightfall. At this time, not only light perception decreases, but also the field of view narrows. Because of this, a person does not see at all 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 he alth, but also life.
Hemeralopia often causes disturbances in dark adaptation. It is difficult for the eyes to get used to the differences in light in the process of transitions from well-lit areas to darker ones. And if oncoming cars shine with their headlights, a driver with such a pathology will be blinded in the truest sense of the word. Therefore, the conclusion is obvious - driving 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 road users.
