The film ‘Owl’ is a thriller that depicts the struggle of a blind acupuncturist who can only see at night to reveal the truth after witnessing the death of the Crown Prince. Actor Ryu Jun-yeol plays a blind acupuncturist who can only see at night. Learn about ‘week blindness’, a condition that cannot be seen during the day and can only be seen slightly at night.
If you can’t see better during the day, let’s suspect blindness ㅣ Source: Getty Image Bank
What is the cause of day blindness, where a clear night is better than a cloudy day?
A representative element that enables us to see something clearly is ‘light’. In the dark with little light, it is difficult to distinguish even the proper form. ‘Night blindness’, as we commonly know it, refers to symptoms of difficulty distinguishing between objects in dimly lit or dark areas. The opposite concept is ‘week blindness’. Unlike night blindness, night blindness is more difficult to see during the day than at night.
The eyeball contains nine tissues. The cornea bends light together with the lens to see objects, the lens bends light with the cornea to see objects, the iris controls how much light enters the the eye (the pupil refers to the hole between the iris), protects the eye The sclera (commonly referred to as the white of the eye), the choroid (uvea) which prevents light from leaking into the pupil, the retina, which allows around 130 million photoreceptors to identify light and see objects, identify objects clearly and accurately and The macula collects, the optic nerve which transmits light information received by the retina and the macula to the brain, and the vitreous body which fills a large area of the eye.
The iris, which controls the amount of light, closes when too much light enters, and the pupil narrows. Conversely, when the light is low, the iris opens and the pupil dilates. Light reflected from objects is reflected on the retina through the cornea and the lens. At this time, if the lens becomes cloudy and the field of view becomes cloudy, it is difficult see the surroundings even though there is enough light. This symptom is called ‘week blindness’. A typical symptom of the opacity of the lens is a cataract. In other words, primary blindness is one of the symptoms often found in the early stages of cataract.
Why does night blindness occur when the eyes are dark at night?
There is a difference between night blindness and day blindness, which we know in common, from their causes. Night blindness is a condition where you cannot see well at night, and it has various causes. Among them, the representative causes are vitamin A deficiency, retinitis pigmentosa, and non-progressive congenital night blindness.
In order for our eyes to detect light, the photoreceptor must detect the light and transmit it to the brain via the optic nerve. At this time, a visual substance called rhodopsin (a protein that detects red light in the retina of the eye) from the photoreceptor cell is broken down by light. Vitamin A is an ingredient necessary for the production of rhodopsin, and a lack of vitamin A can cause night blindness. In addition, night blindness can occur due to retinitis pigmentosa, a progressive disease that occurs due to problems with the function of photoreceptors. It mostly appears in people in their teens and 20s, and the cause is unknown, but it is known to be a disease caused by genetic abnormalities. Congenital night blindness Congenital took care of.
Suspicion of cataract in case of primary blindness
Unlike night blindness, which is caused by different causes, day blindness usually appears as an early symptom of cataract. Cataract is a disease where the lens in the eye becomes opaque due to some cause, causing vision impairment. It can be congenital due to genetic causes or rubella infection during early pregnancy, but it can also appear acquired due to aging, trauma, systemic disease, eye inflammation, or toxins.
Cataract is the most common surgical treatment in Korea. According to the 2020 major surgery statistical yearbook published by the National Health Insurance Corporation, the number of cataract surgeries was the highest at 702,621. It was followed by general spine surgery (188,394 cases), hemorrhoid surgery (169,669 cases), cesarean section (146,427 cases), and cholecystectomy (86,274 cases). Cataract, a representative geriatric disease, is caused by changes in the protein structure of the lens during the aging process, and is also affected by the living environment, such as prolonged exposure to ultraviolet rays. It can also occur as a complication of diseases such as high blood pressure and diabetes. In recent years, as the use of digital devices such as smartphones and computers has increased, cataracts have also increased in relatively young age groups.
Unlike normal, cataracts should be suspected if you have difficulty distinguishing between objects during the day when there is enough light. Cataract is not a disease that requires quick treatment, but since there can be differences in the speed and degree of progression, it is good to visit an ophthalmologist and get a detailed diagnosis if blindness occurs. In particular, if primary blindness appears in people over the age of 40, there is a high probability that cataracts develop. Severe blindness can make outdoor activities as well as indoor lighting difficult. If primary blindness is not treated, it can lead to a vicious cycle where the pupil turns white in the final stage and if left untreated, glaucoma occurs.
Cataract and blindness should be prevented by improving lifestyle…
Cataracts develop slowly with no specific symptoms and are easy to detect after symptoms have worsened. Therefore, if primary blindness, an early symptom of cataract, appears, efforts are needed to slow the progression of the cataract.
The primary treatment for cataract is surgery, but if detected relatively early, lifestyle changes can slow the progression of cataract. Since cataracts are mainly caused by aging of the eyes, the best way to prevent aging is to reduce the use of electronic devices such as smart phones. If it is difficult to reduce the time of using electronic devices for business reasons or realistically, you should make it a habit to reduce eye fatigue from time to time.
UV rays also have a significant effect on the aging of the eyes. It is recommended to wear sunglasses or bring a wide-brimmed hat or safety goggles to block UV rays.
Additionally, taking eye nutrients that include astaxanthin, lutein, and anthocyanin can help prevent cataracts. In addition, keeping the temperature and humidity indoors at an appropriate level so that the eyes do not dry out, and living in bright lights is also a good practice to prevent eye aging and cataracts.
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