Causes
In clear light, light reflected from an object enters the eye and is bent by the cornea and then by the lens to focus the image on the retina. Receptor cells in the retina and cones convert light impulses into nerve signals that are transmitted to the visual cortex of the brain.
Night vision is impaired due to insufficient light to reflect the object. The intensity of the reflected light is stimulated by receptor cells that adapt to new conditions. The problem of night blindness occurs when there is an abnormality in the stimulation of these photoreceptors. One of the culprits of the condition is vitamin A deficiency, which affects the level of rhodopsin, a pigment in receptors involved in adaptation processes.
This affects receptors in the retina, further contributing to night blindness.
Other reasons contributing to the development of hemeralopia:
- birth defects;
- retinitis pigmentosa;
- cataract (partial or complete clouding of the lens);
- nearsightedness (myopia);
- glaucoma (a chronic pathology in which fluid pressure in the eye increases);
- uncontrolled diabetes mellitus;
- diabetic retinopathy.
Scientists have learned that cone dystrophy is an eye disorder that is inherited from parents and leads to poor visibility in the dark. This occurs due to the loss of cone cells as well as the photoreceptors on which central and color vision depend.
Hemeralopia is caused by the use of epileptic drugs. Adi syndrome is also considered a known cause of the disease. It is a neurological disorder seen mainly among women.
Another genetic condition is Cohen's syndrome. It sometimes leads to hemeralopia. It is observed in obesity, in the case of craniofacial dysmorphism (occurs due to the 8q22-23 mutation).
Opening up to let in more light
Your pupils are the black areas in front of your eyes that allow light to pass through. They appear black because the light that reaches them is absorbed inside the eyeball. It is then translated by your brain into your perception of the world.
You've probably noticed that the pupils can change size in response to light. Outside on a bright sunny day, your pupils become very small. This puts less light into the eyes as there are many available.
When you go to a dark place, your pupils open to become as large as possible. This expansion allows your eye to collect more light than is there.
But from the smallest size to the widest pupil, your pupil can only increase its area by 16 times. You can clearly see the lateral changes in light levels by a factor of much more than a million. So there must be something else going on here.
Treatment
Doctors and scientists have not yet found a way that will eliminate the disease forever. The causes of this condition are so numerous and varied that it is impossible to establish treatment tactics without knowing the etiology of hemeralopia.
Congenital night blindness cannot be treated. It is possible to prevent the progression of the disease with the help of preventive measures, but it is impossible to cure it.
If the cause is a cataract, it is removed surgically. Additionally, take vitamin A; there is enough of it in carrots, tomatoes, spinach, cheese and apricots. It is found in large quantities in fish roe and cod liver.
Sometimes vitamin drops are prescribed to be taken into the eyes. This way, beneficial substances penetrate the eye structures faster, preventing the progression of the disease and slightly improving dark adaptation.
These medications normalize oxygen supply to tissues and restore impaired microcirculation. An excellent remedy is Riboflavin.
Why does night blindness occur?
In modern medicine, congenital and acquired night blindness is determined. If a person is diagnosed with congenital night blindness, then we are talking about a genetically determined disease. The acquired form of the disease is a functional illness.
Acquired hemeralopia develops in humans due to the influence of a number of factors. First of all, the causes of hemeralopia may be diseases of the retina. These are pigmentary degeneration and retinal detachment , as well as inflammatory processes . Night blindness in humans can develop due to degenerative processes of the macula, disorders of the choroid, inflammatory processes of the optic nerve, and myopia . Sometimes treatment for hemeralopia is given to patients who are later found to have cataracts or glaucoma . Sometimes decreased vision in the evening is observed in a person who has recently received a traumatic brain injury. Also, similar visual impairments can occur if a person constantly works in very poor lighting or reads in incorrectly set light. In some cases, nyctalopia can be caused by exposure to ultraviolet radiation on the eyes. This occurs due to exposure to bright sun and the influence of dazzling snow on the eyes.
Another important factor that can provoke night blindness is a lack of vitamins A and B2 in the human body. This explains the fact that night blindness is often observed in people suffering from general vitamin deficiency .
If we are talking about risk factors for the development of nyctalopia, then in this case the age factor should be noted. After forty years, a person experiences a slowdown in all processes that occur in the body. As a result, the nutrition of the retina deteriorates, and vision in the twilight decreases.
Prevention
There are certain measures and healthy habits that can help protect your vision and prevent the development of the disease.
Diet food
It is important to adjust your diet and eat a balanced diet. Spinach and other greens are good for your eyesight.
Vitamin A, found in abundance in carrots and sweet potatoes, is essential for eye health. It gives the necessary impetus. Vitamin A must be consumed regularly if there are problems with dark adaptation.
Strawberries and mangoes contain vitamin C, which is beneficial in fighting eye diseases. Certain types of freshwater fish are recommended by most nutritionists because they provide omega-3 in large proportions.
Avoid sun exposure
UVA and UVB rays induce radiation that leads to cataracts and macular degeneration. The best way to protect your eyes from UV rays is to wear sunglasses every time you go outside.
Moisturizing the eyes
Dry eyes stress the retina and can lead to hemeralopia. Using electronic devices for a long time leads to dry eye syndrome.
If after working at the computer you feel itching, pain or noticeable redness, use moisturizing drops.
Quitting nicotine
Smoking leads to the production of cyanide. This substance harms the visual organs and leads to cataracts, dry eye syndrome, and hemeralopia.
If a person uses 1 pack of cigarettes daily, this leads to macular degeneration.
Regular doctor visits
The best way to prevent eye diseases is to regularly visit an ophthalmologist and undergo an examination. Early diagnosis will prevent the progression of severe pathologies, including hemeralopia.
Some illnesses that lead to poor visibility in the dark can be prevented. For example, glaucoma, diabetic eye diseases.
How does night vision work?
At dusk, the intensity of light decreases, cone cells stop working, as a result of which a person does not distinguish colors. But here the rods come into play; they determine the ability to see in low light. They synthesize the pigment rhodopsin, which is responsible for adapting vision to darkness. When exposed to light, this pigment is destroyed, so the rods understand that they need to stop working. But once again it will recover again, and this will happen with the participation of vitamin A.
Rhodopsin is not produced instantly, so it takes us some time to adapt to the dark. In about five minutes, sensitivity increases by 30%, after 15 minutes it will become 60% higher, maximum addiction will occur in about an hour, this is exactly the time required to produce the required amount of pigment.
In this case, the pigment is destroyed instantly. For this reason, if a person sees a bright light in the dark for literally three seconds, he will have to adapt again. The truth is not that long, 10 minutes will be enough.
Brittle hair and nails
Various factors can cause hair and nails to become brittle. One of them is biotin deficiency.
Biotin, also known as vitamin B7, helps the body convert food into energy. Biotin deficiency is very rare, but when it occurs, brittle, thinning or splitting hair and nails are among the most noticeable signs.
Other symptoms of biotin deficiency include chronic fatigue, muscle pain, cramps, and tingling in the arms and legs (1).
Pregnant women, heavy smokers or heavy alcohol drinkers, and people with digestive diseases such as leaky gut syndrome and Crohn's disease are at greatest risk of developing biotin deficiency.
In addition, long-term use of antibiotics and some anticonvulsants is a risk factor (2).
Eating raw egg whites can also cause biotin deficiency. This is because raw egg whites contain avidin, a protein that binds to biotin and can reduce its absorption (1, 3, 4).
Biotin-rich foods include egg yolks, organ meats (animal liver, kidneys and hearts), fish, meat, dairy products, nuts, seeds, spinach, broccoli, cauliflower, sweet potatoes, yeast, whole grains and bananas (5 , 6).
Adults with brittle hair or nails can try a supplement that provides the body with about 30 micrograms of biotin per day.
However, the benefits of taking biotin supplements have been poorly studied, so a diet rich in biotin may be a better choice (7, 8, 9).
Summary:
Biotin is a B vitamin involved in many body functions. It plays an important role in strengthening hair and nails. Deficiency of this vitamin is generally rare, but can occur in certain cases.
Scaly patches and dandruff
Seborrheic dermatitis (SD) and dandruff are part of the same group of skin conditions that affect the oil-producing areas of your body.
Both cause itching and flaking of the skin. Dandruff is mainly limited to the scalp, while seborrheic dermatitis can also appear on the face, upper chest, armpits and groin.
The likelihood of these skin diseases is highest during the first three months of life, puberty, and adulthood.
Research shows that both of these conditions are also very common. Up to 42% of infants and 50% of adults may suffer from dandruff or seborrheic dermatitis (29, 30).
Dandruff and seborrheic dermatitis can be caused by many factors, including a diet low in nutrients. For example, low blood levels of zinc, niacin (vitamin B3), riboflavin (vitamin B2), and pyridoxine (vitamin B6) may play a role (13, 29, 31).
The exact relationship between a nutrient-poor diet and these skin diseases is not fully understood. However, people suffering from dandruff or seborrheic dermatitis are advised to consume more of these nutrients.
Foods rich in niacin, riboflavin, and pyridoxine include: whole grains, poultry, meat, fish, eggs, dairy products, organ meats, legumes, green vegetables, starchy vegetables, nuts and seeds (15, 16, 17).
Seafood, meat, legumes, dairy products, nuts, and whole grains are all good sources of zinc (32).
Summary:
Dandruff and scaly patches on the scalp, eyebrows, ears, eyelids and chest can be caused by low intake of zinc, niacin, riboflavin and pyridoxine. Adding these nutrients to your diet may help reduce symptoms.
Why can't people see at night?
In general, to be completely honest, cats don’t see that well in the dark either. It’s just easier for them to navigate in a space with a limited amount of light due to the fact that their pupils are able to reflect even those rays of light that human eyes cannot perceive.
Not so long ago, scientists found out that in addition to the structure of the pupils, it is also a matter of DNA. But a person is not able to accept someone else's DNA. Especially in light of the fact that people and the same owls are completely different species.
However, for those who often find themselves in relative darkness, it is worthwhile to train their eyes in order to see even in such circumstances. Of course, it is impossible to quickly learn to use your eyes this way. However, regular training and following a few rules will help you achieve these results as quickly as possible.
Dancing in the dark
The human eye is able to see well day and night thanks to movement. That is why for all those who want to learn how to easily navigate in the dark, there is a simple recommendation. It lies in the fact that you cannot concentrate on any one object. Let your eyes dance a little. Why is this necessary?
This will prevent your eyes from focusing on a specific light source. Using this advice, it will be easier for you to cope with the task expressed in the paragraph above.
