What is Night Blindness?
Night blindness or nyctalopia, as it is medically known is the impairment of vision at night time or in low light conditions. Blindness and night blindness are very different. Nightblindness is the result of a vitamin A deficiency and it is reversible and preventable. Most people find it difficult to see during the dark or under poorly illuminated surrounding. However, for people who suffer from night blindness, this issue is little more severe. Night blindness can be defined as a condition where the people suffering from it find it extremely hard to see during the night or under poorly lit surroundings. The term night blindness is actually quite misleading as it implies that one is sightless at night, but as explained above this is not the case.
When lighting is dim, the eye must adapt. Although night blindness adversely affects a person’s ability to see in dim light, it does not cause complete blindness. It may create problems seeing road signs while driving at night. Night blindness does not mean that one is completely incapable of seeing, but rather means that the vision is compromised. It is imperative that night blindness is not a disease in itself, it is a symptom manifested due to underlying issues like retinal problems. It isn’t a disease, but rather a symptom of another problem like untreated nearsightedness. Night blindness affects pre-school children and pregnant women the most. According to a report by WHOM, night blindness globally impacts 0.9% of children and 7.8% of pregnant women.
Causes for Night blindness
The problem comes from a disorder of the cells in your retina that allow you to see dim light. It has many causes
- Glaucoma: Glaucoma refers to a group of eye conditions where damage to the optic nerve, which connects the eye to the brain, causes pressure in the eye. This may impair vision, which can be permanent. Glaucoma is caused mainly due to an excessive fluid buildup in the front section of the eye which in turn leads to increased pressure in the eye which damages the optic nerve.
- Retinitis Pigmentosa: This is a rare genetic condition which alters the way the eyes respond in dim light. The retinal photoreceptor cells namely the rods and cones begin to degenerate. Hence, there is no cure for this disease and ultimately leads to blindness.
- Vitamin A deficiency : One of the most common causes for night blindness, especially in developing countries like India, is the deficiency of Vitamin A. Malnourishment and an imbalanced diet are at the root of night blindness in little children. The whole concept of keeping your eye healthy by eating more carrots comes as a precautionary practice to prevent young kids from developing VDA.
- Nearsightedness: Blurred vision at night time can be caused by an untreated case of myopia or nearsightedness. Nearsightedness also is known as Myopia in medical terms is a visual condition that restricts the people affected with it to see clearly the things that are located far away. Myopia is also a cause for night blindness as this refractive error tends to become severe when the amount of light entering the eyes is less.
- Cataract: This is a disease that is associated with aged people and involves having a poor vision due to the clouding of the lens of the eye. Night blindness could manifest itself as a symptom of People suffering from cataract has serious problems seeing in the night, they most often also find it difficult to process focused light and suffer from issues such as glare while driving.
- Diabetes: Diabetes serious damage to one’s nerves and tissues causing serious health conditions. Diabetic neuropathy can also affect the optic nerve causing vision problems such as night blindness. Night blindness is only one of the less serious symptoms of diabetes, there are instances where the retina has visible leakage of blood due to diabetes which can lead to serious injuries in the eye.
Symptoms for Night Blindness
Night blindness is a vision condition that makes you see very poorly in dim lit surroundings. The most evident symptom and the only one is the inability to see clearly in poor lighting and during night time. There are various conditions that could be the underlying cause for night blindness. Night blindness affects people of all ages from young children to old people. Hence, it is important to identify the signs and symptoms of the disease and avail treatment at the earliest. Some of the best treatment option based on the underlying cause of night blindness in listed in the table below.
Diagnosis and Treatment
Certain cases of night blindness are curable while others are not, depending upon the cause for the onset of the disease. The method of treatment for night blindness is aimed at the underlying causal factor behind the same. As you have read in the previous sections there are various factors that can cause night blindness. The treatment option will be decided by your eye doctor once he/she confirms the underlying cause behind the symptom of night blindness.
- Tests to measure visual sharpness, pupillary light reflex and the ability to see colors, refraction test to verify the prescription for spectacles or contact lenses.
- Treatment may include wearing specific types of glasses or contact lenses, which can help to support correct vision.
- Cataract surgery is a simple procedure that removes the fogginess on the eye lens and improves eyesight and reduces night blindness.
- When the cause is a lack of vitamin A, treatment involves adding more Vitamin A to the diet. Good sources of vitamin A include eggs, fortified cereals, fortified milk, orange and yellow vegetables and fruits, cod liver oil and dark leafy green vegetables.
- Retinitis pigmentosa currently have no effective treatments, although certain eye devices and therapy services may improve symptoms and quality of life.
- Myopia or nearsightedness will be kept under control by the use of vision correction glasses or contact lenses.
How to prevent Night Blindness
- Retinitis pigmentosa currently has no effectivetreatments, although certain eye devices and therapy services may improve symptoms and quality of life.
- Take vitamin A in diet. Foods rich in vitamin A include dairy products, egg yolks, fish liver oil and liver, yellow-green fruits and vegetables like papaya, carrots, mangoes, melons, bell peppers and spinach.
- Keeping a regular track of your blood sugar level will make it easy for you to stay away from night blindness that is caused due to night blindness.
- Food that is rich in these nutrients will significantly reduce the chances of cataract to occur.