Night blindness How often men are struck by a fatal illness that interferes with promising fruitful relationships! And this disease is not impotence at all. More like night blindness...Yes, yes! It's sad, but true! Very often men, who, as we know, love primarily with their eyes,

Night blindness is poor, impaired vision in low light (eg, darkness, twilight, night, etc.). This means that in good light a person has completely normal vision, but if he goes into any room with a lack of light or it gets dark outside, then he sees poorly. That is, when darkness sets in or lighting decreases, a pronounced deterioration in vision occurs.

Medical designation of the disease night blindness and its

synonyms

Night blindness is the popular name for the disease, which in the Russian terminological tradition is referred to as hemeralopia. In general, the term “hemeralopia” is formed from three Greek words- “gemer”, “ala” and “op”, which are translated into Russian as “day”, “blind” and “sight”, respectively. That is, the final translation of the term “hemeralopia” is “day blindness”. As you can see, the literal translation of the term does not reflect the essence of the disease, since with night blindness a person sees poorly in the dark, that is, at night and in the evening, and not during the day. However, this particular term in non-English-speaking countries, including the post-Soviet space, has been used to refer to poor vision in the dark for a long time (more than a hundred years), since a mistake was once made in the name of the disease and was subsequently not corrected. It is in this way, based on the “established” name, that the term “hemeralopia” has come to this day to designate a widely known disease - night blindness.

In English-speaking and many other countries, the medical term for night blindness is “nyctalopia.” The term "nyctalopia" is also derived from the three Greek words "nyct", "ala" and "op", which are translated as "night", "blind" and "sight", respectively. Accordingly, the final full translation of the term “nyctalopia” is “night blindness”. As you can see, nyctalopia fully corresponds to the essence and meaning of the disease, popularly called night blindness. However, this linguistically and functionally correct term is used to refer to night blindness only in English-speaking countries and former colonies of Great Britain.

Due to these features, night blindness is called hemeralopia in Russia, and nyctalopia abroad. Therefore, the terms “nyctalopia” and “hemeralopia” in the mouths of English-speaking and Russian-speaking doctors, respectively, will be synonyms, denoting the same disease, known by its popular name as night blindness.

Night blindness - the essence of the disease and general characteristics

Night blindness is poor, low vision in poor lighting. Moreover, vision becomes poor only in the dark or in poorly lit rooms, but in the daytime or in bright light a person sees perfectly. Night blindness can be either an independent disease or a symptom of some other pathologies of the human eye.

Both men and women are equally susceptible to night blindness. However, at menopausal age (about 50 years), women develop this pathology more often than men, which is due to hormonal and powerful endocrine changes that occur in their body and affect the functioning of all organs and systems, including the eyes. Hormonal changes during menopause increase the risk of developing night blindness, so at the age of 50 more women suffer from this disease than men. In all other age categories, the ratio of men and women suffering from night blindness is the same and is approximately 1.1.

Night blindness never develops among the peoples of the Far North (for example, the Khanty, Mansi, Eskimos, Kamchadals, etc.) and the Aborigines (Indians) of the Australian continent. This is due to the fact that the eyes of the peoples of the Far North during the course of evolution have adapted to vision in the dark, since most of the time they are forced to live in polar night conditions. The aborigines of the Australian continent also, for some reason, during the course of evolution, acquired the ability to see in the dark 4 times better compared to representatives of the Caucasian race.

The essence of night blindness is that as soon as for any reason a person finds himself in a situation with poor lighting, he ceases to clearly distinguish the outlines of objects and their shape, everything seems to him in a fog. The colors are practically indistinguishable; everything seems simply monochromatic and darkened. People are especially bad at distinguishing the color blue. He often sees dark spots or shadows on objects. In addition, the field of view is significantly narrowed. When moving from darkness to a well-lit room or space, colored spots may appear on objects. To clearly imagine the essence of night blindness, you need to look at Figures 1 and 2, which depict exactly how a person with normal vision and someone suffering from hemeralopia sees the surrounding picture.

Figure 1 – Perception of the surrounding space in low light (at dusk) by a person with normal vision.

Figure 2 - Perception of the surrounding space in low light (at dusk) by a person suffering from night blindness.

Night blindness has been known to mankind since ancient times and is associated with any disruption of the retina or optic nerve. Hemeralopia significantly reduces a person’s quality of life, since it can provoke a fear of the dark and severe disorientation in the dark, which is fraught with injuries and dangerous situations that arise when performing normal activities.

Classification and characteristics of types of night blindness

Depending on the causes of occurrence, all types of night blindness are divided into three types:

1. Congenital night blindness;

2. Essential night blindness;

3. Symptomatic night blindness.

Congenital night blindness It is inherited and manifests itself at an early age - in children or adolescents. The causes of congenital night blindness are often various genetic diseases, such as, for example, Usher syndrome or hereditary retinitis pigmentosa.

Essential night blindness is a functional disorder of the retina caused by a deficiency of vitamins A, PP and B2 or the microelement zinc. The causes of essential night blindness are various conditions in which the intake or absorption of vitamins A, PP and B2 is impaired. for example, poor quality poor nutrition. starvation. liver or digestive tract diseases, alcohol abuse, rubella. poisoning by any toxic substances or prolonged exposure to bright light.

Symptomatic night blindness develops against the background of various eye diseases associated with damage to the retina or optic nerve. In this case, night blindness is a symptom of the following severe eye lesions - high myopia, glaucoma. taperetinal dystrophies. chorioretinitis, optic nerve atrophy, siderosis.

In addition to the listed types of hemeralopia, doctors and scientists identify another condition called false night blindness. In this case, a person’s vision is impaired and deteriorates in the dark and in low light conditions due to simple eye fatigue, for example, after working for a long time with computer monitors, televisions, locators or other devices, etc. False night blindness is not a disease, but reflects a functional deterioration in the functioning of the eye analyzer, resulting from its overstrain. After a person gives his eyes a good rest, his vision will be completely restored. However, if a person often strains his eyes excessively and does not give them quality rest, this can lead to serious illnesses and permanent vision loss.

Causes of night blindness

The immediate cause of night blindness is a decrease in the number of specific cells in the retina, which are responsible for the perception of images of the surrounding space in low light conditions.

It is known that the retina of the eye has two main types of light-sensitive cells, called rods and cones (see Figure 3). Rods are responsible for twilight vision, and cones, on the contrary, for vision in bright light conditions. Normally, there are many more rods on the retina than cones, since a person finds himself in low-light situations much more often than in conditions of ideal and bright lighting.

Normally, the retina of the eye contains approximately 115,000,000 rods and only 7,000,000 cones. The cause of night blindness is either a violation of the structure of the rods or a decrease in their number. Most often, the immediate cause of night blindness is the breakdown or disruption of the synthesis of the special visual pigment rhodopsin, which is the main functional unit of the rods. As a result, the rods lose their normal structure and cease to function fully, that is, the person develops night blindness.

Figure 3 - Rods and cones found on the retina.

The cause of congenital night blindness is a genetic mutation that is inherited. This mutation or breakdown in genes does not lead to the development of severe congenital deformities, but only causes night blindness - a disease with which a person can easily live. And since night blindness is a disease compatible with life, a fetus with such a defect in the genes is not “discarded” through spontaneous miscarriage. but continues to develop normally. Night blindness is often combined with other genetic diseases, such as Usher syndrome or hereditary retinitis pigmentosa.

The causes of symptomatic night blindness are various severe diseases associated with damage to the retina of the eyes:

• High myopia (myopia more than -6);
• Glaucoma;
• Pigmentary dystrophies of the retina;
• Chorioretinitis;
• Optic nerve atrophy;
• Siderosis (deposition of iron salts in the tissues of the eye).

Symptomatic night blindness is not an independent disease, but acts exclusively as a sign of another, more serious pathology of the retina.

Essential night blindness develops under the influence various factors, causing deficiency or impaired absorption of vitamins A, PP and B2. These factors may include the following conditions or diseases:

Poor nutrition, in which there is a deficiency of vitamins (A, PP and B 2) and minerals; Starvation; Anemia; Past rubella or chickenpox;
• Liver diseases;
• Diseases of the digestive tract;
• Chronic alcohol abuse;
• Any poisoning (intoxication due to infections, poisoning, alcohol or tobacco abuse, etc.);
• Exhaustion of the body;
• Treatment with drugs that interfere with the absorption of vitamin A, for example, Quinine, etc.;
• Prolonged exposure to bright light.

Vitamin A deficiency is most important for the development of night blindness, since this compound is the substrate for the synthesis of visual pigment. Therefore, the risk of night blindness is highest in people suffering specifically from vitamin A deficiency.

However, essential night blindness does not develop immediately, since at least two years may pass from the onset of chronic vitamin A deficiency to the appearance of clinical symptoms. This is due to the fact that the reserves of vitamin A present in the tissues of the human body will last for about one year, provided that this compound does not come from the outside at all. However, in practice, there are no situations when vitamin A does not enter the human body at all, so reserves are depleted over a year and it takes longer to form clinical manifestations Night blindness occurs for at least two years.

Symptoms of night blindness

Regardless of the variety, night blindness manifests itself with the same symptoms. however, their severity may vary. With night blindness, a person's vision deteriorates greatly when exposed to low light conditions, for example, twilight, at night, in a room with a small number of lamps, etc.

In night blindness, vision adaptation is impaired when moving from a relatively light room to a dark room and back. This means that a person cannot orient himself for a long time and begin to see normally when he moves from one level of illumination to another. Moreover, this is observed both during the transition from dark to light, and vice versa, from a lighted place to a darkened one.

In poor lighting, a person’s field of vision narrows, and he sees the picture of the world around him in a very narrow frame, as if through a pipe or a small window. In addition, a person ceases to clearly see the shape and size of objects, and also does not distinguish colors. The difference between blue and yellow colors is especially bad in case of night blindness. A person begins to notice that he, in principle, does not perceive colors correctly, since a violation occurs Purkinje effect. The Purkinje effect is the phenomenon of different perceptions of colors as light levels decrease. Thus, at dusk, red colors appear darker, and blue colors, on the contrary, appear lighter. The big picture seen in dark, muted tones, there is a feeling of vision as if in fog.

In addition, with night blindness, the eye is insufficiently sensitive to light, so a person needs very bright lighting to read or write. The need for bright light for writing and reading against the background of normal vision at dusk is the first sign of the development of night blindness.

Night blindness often causes decreased vision. This means that in normal lighting conditions a person has 100% vision, but at dusk it drops by several units. On the conjunctiva of the eye with essential night blindness are found Iskersky-Bito plaques .

Poor vision in low light conditions can frighten a person and ultimately cause a fear of the dark. Especially often, fear of the dark develops against the background of night blindness in children with a congenital disease.

Diagnosis of night blindness

Diagnosis of night blindness is based on a person’s characteristic complaints. Based on complaints, the doctor suspects night blindness and then confirms the disease with certain instrumental studies.

To confirm night blindness and determine its type, the following diagnostic tests are performed:

Fundus examination. In essential hemeralopia, the fundus of the eye is normal; in symptomatic and congenital hemeralopia, it looks like the pathology that caused night blindness.
• Detecting the presence of plaques on the conjunctiva of the eye.
• Perimetry (narrowing of visual fields is revealed).
• Adaptometry. A person looks at the bright screen of the device for 2 minutes, after which an object is placed on it and the time after which it becomes visible to the person being examined is noted. The norm is no more than 45 seconds. With night blindness, a person sees an object on the screen later than 45 seconds.
• Refractometry.

Night blindness - treatment

Treatment for night blindness depends on the type of disease. So, with symptomatic night blindness, treatment is carried out for the underlying disease that caused the impairment of twilight vision.

The principles of therapy for essential and congenital night blindness are the same, however, their success and effectiveness are different. Congenital night blindness is practically untreatable, and a person develops a persistent decrease in vision. Essential night blindness, on the contrary, responds well to treatment, since it is associated with a deficiency of vitamins A, PP and B.

The main method of treating essential and congenital night blindness is taking synthetic vitamins A, PP and B2. You should also include foods containing these vitamins in your diet. Diet, rich in vitamins A, PP and B 2 in combination with taking vitamins medicines, is the main treatment for all types of night blindness.

To treat night blindness, adults need to take vitamin A 50,000–100,000 IU per day, and children 1000–5000 IU per day. Riboflavin (B 2) adults and children should take 0.02 g per day.

Foods rich in vitamins A, PP and B2. that you need to include in your diet to treat night blindness are the following:

Taking vitamins and following a diet to treat night blindness is necessary for several months in a row. The exact timing of treatment is determined by an ophthalmologist.

Diet and vitamin intake are also necessary in the complex treatment of symptomatic night blindness, along with the treatment of the underlying disease that caused vision impairment. However, the essential type of the disease is completely curable, the congenital type is practically not treatable, and with symptomatic night blindness, everything depends on the success of treatment of the underlying disease.

In addition, if you have night blindness, you must avoid bright headlights and fluorescent lamps, and in the evening, even if you have mild myopia, you must wear glasses.

Night blindness - treatment with folk remedies

Traditional treatment for night blindness involves the use of various decoctions, infusions and juices and other preparations from plants and products containing vitamins A, PP and B2. necessary for the normal functioning of the eyes.

So, effective traditional methods Treatments for night blindness are the following infusions, juices, decoctions and gruels:

Mix 2 parts each of blueberry leaves, linden flowers and dandelion (leaves, roots and flowers), add 1 part each of buckwheat and sea buckthorn leaves. Pour a tablespoon of the prepared herbal mixture into a glass of boiling water and heat in a water bath for 15 minutes. Then leave in a warm place for half an hour, strain and take the prepared decoction one glass three times a day after meals;
• Pour a teaspoon of wildflower flowers into a glass of boiling water and leave for 10 minutes. Take the finished infusion one tablespoon three times a day after meals;
• Pour a teaspoon of blue cornflower flowers into a glass of boiling water and leave for one hour. Strain the infusion and take 1/4 cup three times a day half an hour before meals;
• Pour one tablespoon of blueberries into a glass of boiling water and leave for four hours. Strain the finished infusion and take half a glass three times a day, regardless of meals;
• Eat sea buckthorn berries fresh or frozen, two glasses a day;
• Pour three tablespoons of sea buckthorn berries into a glass of boiling water and leave for half an hour, then strain. Drink the prepared infusion twice a day an hour after meals. You can add honey or sugar to the infusion to improve the taste;
• Pour two tablespoons of nettle leaves and stem tips with a glass of boiling water, leave for an hour, then strain. Take the finished infusion 1/3 cup three times a day half an hour before meals;
• Take half or a whole glass of fresh carrot juice 2-3 times a day, half an hour before meals. The juice should be prepared immediately before use and stored for no more than 30 minutes;
• Take blueberry juice diluted three times a day before meals. For each dose, you need to dilute a tablespoon of juice in half a glass of water;
• Take half a glass of grape juice three times a day, half an hour before meals;
• Sprout wheat grains. then grind them in a meat grinder. Pour a tablespoon of sprouted wheat grains into a glass of boiling water and heat in a water bath for half an hour. Then leave for 15 minutes, then strain. Take the finished decoction 1/3 cup three times a day, regardless of meals;
• Fish oil take 30–40 ml three times a day;
• Every day, eat a small piece of lightly fried beef liver;
• Take a teaspoon of sea buckthorn oil three times a day before meals.

Before use, you should consult a specialist.