Night Blindness
Night blindness, or chicken black as it is commonly used in society, is a vision problem that manifests itself in the eye's inability to adapt to dark environments. A healthy human eye quickly adapts to dim light. . Although night blindness affects the person's ability to see adequately in low light and darkness, it does not cause complete blindness.
This problem is known in the medical literature as nyctalopia. It is not considered a disease in itself because it is a result of different diseases. The most common of these diseases is retinitis pigmentosa. Retinitis pigmentosa is an eye disease that affects the photoreceptor cells responsible for vision in the retina, the light-sensing layer of the eye. The disease progresses progressively by disrupting the structure of these cells and mostly occurs due to hereditary reasons. The age at which the disease occurs and how it progresses and its degree vary from person to person. The disease occurs in both eyes. Although permanent treatment of the disease is not possible, it is possible to apply a treatment that slows down its progression. The diagnosis of the disease can be made by visual field test, electroretinography and fundus examination.
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What is Night Blindness (Chicken Black)?
Night blindness is a problem of decreased field of vision and visual acuity that occurs at night or in poor light conditions. Night blindness is known as nyctalopia in the medical literature. The disease, popularly known as chicken black disease, can occur for many different reasons. However, it is especially characterized by retinitis pigmentosa.
Retinitis pigmentosa disease involves degeneration of photoreceptor cells in the retina, the light-sensitive surface of the eye. From the moment the disease first appears, the eye's response to light changes and light perception becomes difficult. As a result, progressive vision loss results in a narrowing of central vision and a problem seeing in the dark.
Chicken blackness In this disease, also called chicken blackness, complete inability to see in dim light or in the dark is out of the question. The typical feature of the disease is a temporary severe decrease in vision when moving from a high-light environment to a lower-light environment. For this reason, night blindness is not considered a type of blindness, but it is a visual impairment.
There is a late adaptation to low light conditions. Patients have difficulty driving in insufficient light conditions, or they may crash into places in a closed area or trip over various obstacles.
The disease may be congenital or may appear later, and its incidence is higher in men than in women. Although the disease is progressive, it does not cause permanent blindness.
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What Causes Night Blindness?
There are various cells in the retina that enable vision in light and dark environments. These cells ensure visual function by adjusting the light level inside the eye in an environment where light is insufficient. The main reason for the problem of decreased night vision is the deterioration of photoreceptor cells in the retina. As a result of these disorders, various functional problems occur in the perception of light.
One of the factors that cause night blindness is retinitis pigmentosa.
Retinitis pigmentosa is considered a single disease. It is considered a group of diseases that affect vision and the functions of light-sensitive cells behind the retina. The main reason for the disease is genetic transmission due to a similar health problem in the family.
Other causes of night blindness:
- Myopia
- Cataract
- Diabetes
- Vitamin A deficiency
- Glaucoma
- Keratoconus
- Retinitis Pigmentosa
- Usher Syndrome
- Some corneal surgeries and drug treatments
- Inability to provide adequate vision and vision in low-light environments. narrowing of the area,
- Having adaptation problems in vision when entering a dimly lit environment from an environment with a lot of light,
- Sensitivity to light and after being exposed to intense light
What are the Symptoms of Night Blindness (Chicken Black)?
Symptoms of night blindness If it is caused by genetically transmitted retinitis pigmentosa disease, the symptoms and timing of the disease may vary from patient to patient because it is genetically inherited.
Night blindness (chicken black) begins to develop from childhood. However, the first symptoms usually appear at a later age. The main reason for this situation is that the disease starts from the outside of the retina and progresses towards the center, and as a result of the cells in the retina being affected, the visual center undergoes degeneration caused by the disease and ends up developing.
Chicken black, both eyes. However, it is difficult to predict the rate of progression of the disease and the degree of vision loss from the very beginning. Although the disease does not cause permanent blindness, there is a narrowing of central vision and a gradual decrease in vision in low-light environments.
The symptoms of night blindness are as follows:
How to Diagnose Night Blindness?
To diagnose night blindness, a field test is performed to measure the transition of the eyes from light to dark. With this test, the pigment cells in the patient's retina are checked. Finally, the patient's quality of vision in dim light is evaluated.
Electroretinography and fundus examination can also be performed to determine whether there is another eye disease underlying the problem.
Like many diseases related to eye health, early diagnosis is important for treatment. It is beneficial for people with a family history of night blindness to have regular eye examinations for early diagnosis.
How to Treat Night Blindness?
Since more than one disease may play a role in the emergence of night blindness, a definitive diagnosis of the disease underlying the vision problem is required in order to plan a definitive treatment method for the patient. In this context, it is necessary for the person who complains of serious vision loss at night and in dim light to be examined in detail by an ophthalmologist.
Chicken black problem is caused by cataracts or If it is caused by a reason such as keratoconus, surgery may be considered for the patient. By replacing the intraocular lens with a smart lens operation during cataract surgery, the patient can have clear vision at all distances and improvement in night vision can be achieved.
In the treatment of keratoconus disease, hard gas contact lenses or hybrid treatment if the patient meets the appropriate conditions. In addition to the eye straining problem, night vision can also be improved.
If the underlying cause of chicken blackness is diabetes, the aim of the treatment is to control blood sugar. If the cause of the disease is due to vitamin A deficiency, a coordinated treatment process can be followed with different branches.
Finally, if a chicken black eye is detected due to advanced myopia, attempts can be made to treat the eye straining problem.
The most common cause of the disease is retinitis pigmentosa. There is no permanent cure for night blindness caused by retinitis pigmentosa. It is aimed to slow down the course of the disease and increase the patient's quality of life with various supportive medications and supplements used in treatment.