Overview and Facts
Also known as nyctalopia, night blindness is the vision impairment during night or in dim-lit environments. It is one of the most common eye problems. People with night blindness suffer from poor vision at night or in low light conditions.
Light rays travel through the cornea and then land on the retina – the light-sensitive layer of the eye. It is made up of photoreceptor cells or nerve cells that convert light rays into electrical signals. These electrical signals travel to the brain to form the image. There are two types of photoreceptor cells in the retina, namely rods and cones.
Each eye consists of nearly 100 million rods and 3 million cones. Cones can recognize colors, but rods can only observe black and white. Rods help eyes in detecting movement and is responsible for peripheral vision. We can see in dimly lit environments or at night with the help of rod cells. These cells are majorly present in the outer part of the retina.
Due to some reason, if rod cells begin to malfunction, it may lead to night blindness. Nyctalopia is very different from blindness. It is not the complete loss of vision as in blindness, but only affects a person’s ability to see in night.
Night blindness can be caused by other retinal problems or due to vitamin A deficiency. Certain cases of nyctalopia are treatable while a few are untreatable. Generally, knowing the root cause of night blindness can help to treat the condition a better way. A person with nyctalopia encounters difficulties in driving at night, spotting stars or even watching a movie in theatres.
Night blindness majorly affects pregnant women and pre-school age children. According to the World Health Organization (WHO) reports, night blindness globally affects around 7.8% of pregnant women and 0.9% of children. Developing countries witness majority of the night blindness cases due to malnutrition and vitamin deficiency. Around two-third of the global nyctalopia cases are from South East Asia and Africa.
Types and Symptoms of Night Blindness
Types of Night blindness:
Night blindness is broadly divided into two types:
- Congenital Night Blindness: This type of night blindness is present right at the time of birth. Genes play an important role in the development of this type of vision impairment. Congenital stationary night blindness refers to genetic conditions of night blindness that are from birth. It is due to an inherited mutation that affects the retina. The genetic cause of congenital stationary night blindness is either autosomal recessive, X-linked or autosomal dominant. There is no treatment and preventive measures for congenital night blindness.
- Progressive Night Blindness: This type of night blindness is caused by progressive degeneration of the retina. Progressive night blindness develops with age or due to significant vitamin A deficiency. It is mostly seen in the elderly. This can be prevented and treated in most of the cases.
Symptoms of Night blindness:
Some common symptoms of night blindness are as follows:
- Eyes take more time to adjust when the person enters a dimly lit area from a well-lit area
- Difficulty in reading and watching television for extended periods of time
- Difficulty in seeing fellow pedestrians on a poorly lit street
- Difficulty in seeing at night, in dimly lit areas or in darkness during the daytime
- Regularly experiencing dryness in the eyes
- Difficulty in watching stars on a clear-sky night
- Difficulty in driving during night
- Difficulty in walking through a dark movie theater
- Often stumbling on pavements or stairs
Risk Factors of Night Blindness
There are several risk-factors associated with night blindness that are listed below:
- Genetics: Having a family member suffering from night blindness, makes the other members more prone to develop night blindness. An example of this is night blindness due to retinitis pigmentosa, which is linked to genetics.
- Age: The risk of developing night blindness increases proportionately with age. Majority of elderly people suffer from night-blindness. This is initiated by the decreased functioning of eye with age.
- Other Health Conditions: The people suffering from liver disorders, high blood pressure and diabetes are at an increased risk of developing night blindness.
- Diet: A healthy diet is key to maintain overall health in a person. Those who have a vitamin A deficiency tend to develop night blindness or nyctalopia. People residing in developing countries are at increased risk of developing night blindness due to malnutrition and vitamin deficiency.
Do I have Night Blindness?
If you have difficulty in seeing at night, watching television, reading a book for longer durations or feel like your eyes taking much time to adjust in the dark, then it might be a case of night blindness.
However, these symptoms might indicate either night blindness or other eye diseases like myopia, cataracts or retinitis pigmentosa. The impairment of vision at night or in dim-lit environment might also be caused due to Usher syndrome, a genetic condition. So, it is a recommended to visit an ophthalmologist for proper diagnosis of the condition and the underlying cause. After precise diagnosis of the condition, an appropriate treatment, according to the cause, can be initiated.
Causes and Prevention of Night Blindness
Causes of Night blindness:
There are several causes of night blindness:
- Deficiency of Vitamin A: Deficiency of retinol or vitamin A is one of the major causes of night blindness. Vitamin A is an essential component of an eye pigment, known as rhodopsin, which is responsible for vision in dim light conditions. Vitamin A also helps in the normal functioning and differentiation of the cornea and conjunctival membranes. Vitamin A deficiency can cause dry eyes and lead to night blindness. Other eye complications that are also caused by vitamin A deficiency are corneal inflammation and poor vision.
- Inability to Absorb Vitamin A by the Body: Mostly after a liver or pancreas surgery, the body is unable to absorb the required amount of vitamin A from the diet. This might lead to vitamin A deficiency in the body and subsequently, night blindness. Chronic intestinal and liver disorders are also responsible for causing night blindness.
- Deficiency of Zinc: If a person is not consuming the required amount of zinc through diet, it might lead to night blindness. Zinc is vital for vision due to its involvement in enhancing the function of vitamin A in the eyes.
- Other Chronic Diseases: Chronic health conditions like diabetes and high blood pressure can result in night blindness if they are not properly managed through proper medications and healthy lifestyle changes.
- Other Eye Complications: People with cataracts (clouding of eye’s retina) or glaucoma develop night blindness if not treated for these eye conditions. An eye injury can also cause night blindness. Untreated myopia or near-sightedness, may also lead to night blindness. Medications for glaucoma constrict the pupil; thereby, can be a possible reason of night blindness.
- Stress or Anxiety Disorders: Having any anxiety disorder, fear of darkness and excessive stress can lead to night blindness.
- Genetic Conditions: Having certain genetic conditions, such as Usher syndrome or retinitis pigmentosa can cause night blindness. Retinitis pigmentosa is an inherited condition, where dark pigments accumulate in the retina and cause tunnel vision.
Prevention of Night Blindness:
Night blindness, caused by genetic anomalies, such as Usher syndrome and retinitis pigmentosa cannot be prevented. However, the same caused by vitamin A deficiency can be prevented as well as managed by increasing the intake of foods rich in vitamin A. Vitamin A-rich foods are carrots, sweet potatoes, pumpkins, cantaloupes, butternut, squash, mangoes, milk, collard greens, eggs and spinach, among others.
Including foods in one’s daily diet that are rich in minerals, antioxidants and vitamins might prevent the development of cataracts – a major cause of night blindness. Besides, controlling diabetes and maintaining blood sugar level to normal level also help preventing night blindness.
To prevent night blindness, pregnant women should consider having vitamin A and zinc supplements, but only after consulting their doctor. Regular eye checkups can also help prevent night blindness.
Diagnosis and Tests of Night blindness
The diagnosis of Night blindness includes the following:
- Detailed History of Symptoms: An ophthalmologist might ask about the history of the symptoms like when they started, their severity and whether it occurred suddenly or gradually. History of previous eye surgery is also asked. Recent development of fear of the dark or falling frequently might indicate night blindness in children.
- Eye Examination: For examining the eye, an ophthalmologist would perform a slit lamp examination. It involves using a narrow beam of intense light to examine the internal parts of the eye. It helps in viewing any underlying condition or probable cause of night blindness. Certain tests are done to measure pupil’s light reflex, i.e., ability to see colors and visual activity. Likewise, refraction test is conducted to determine prescription for contact lenses or eye glasses. Retinal tests through an ophthalmoscope are conducted to check for any injury in the eye or eye parts. An electroretinogram can also be conducted to measure the response of cones and rods. Visual field tests may rule out any other conditions like stroke or glaucoma.
- Blood Tests: A doctor might conduct blood tests to check vitamin A deficiency or blood sugar level. Blood test might also reveal diabetes or zinc deficiency.
Treatment and Care of Night Blindness
Treatment of Night Blindness:
Night blindness cases due to genetic conditions is untreatable, but the ones caused by vitamin A deficiency, cataracts or nearsightedness can be managed. The treatment of night blindness depends on the severity and underlying cause of the symptoms. The treatment options may include:
- Removal of Cataracts: Cataracts, i.e., clouding in the retina of eyes, can be treated through surgery. The doctor or ophthalmologist will replace the old clouded lens with an artificial clear lens. The night blindness caused by cataracts automatically go away after the surgery.
- Stopping or Changing the Glaucoma Medications: If glaucoma medication is the cause of night blindness, the doctor will ask the patient to stop the drugs or may change the prescription.
- Treating Nearsightedness: If night blindness is caused by myopia or nearsightedness, the ophthalmologist would prescribe suitable glasses to treat the condition.
- Intake of Vitamin A-Rich Foods and Supplements: Increasing the intake of vitamin A through foods like carrots, sweet potatoes, pumpkins, cantaloupes, butternut squash, mangoes, milk, collard greens, eggs and spinach help in treating night blindness caused by vitamin A deficiency. A doctor might also recommend taking supplements for vitamin A and zinc; depending on the requirement of the patient.
Care During Night Blindness:
The following measures should be adopted to improve the symptoms of this eye condition:
- A person with night blindness should not be allowed to drive during night time.
- Use red tinted glasses to focus better during night. These glasses improve night vision.
- Avoid directly looking into the source of light. If a person cannot avoid a direct source,
- covering one eye till the source goes out of the sight can be an alternative.
- Let the eyes adjust naturally to the darkness. One can cover the eyes through sleep mask or sit in a completely dark room for 15-20 minutes before stepping out in the night.
- Keep your eyes moving around to scan the surroundings while keeping it blinking all the time. It would prevent the rods from desensitizing.
- Gently massaging the eyes by pressing the palm against closed eyes can be beneficial.
- Keep the vehicle in condition and check breaks regularly to avoid any accidents due to impaired vision at night.
- Carefully plan the driving route while avoiding dimly lit streets and highways.
OTC Medications and Self-Management Methods for Night Blindness
Over-the-Counter Medications for Night Blindness:
There are no OTC drugs for night blindness or nyctalopia. However, vitamin A and zinc supplements might be consumed to treat or prevent night blindness, but it is advised to consume after consulting your doctor.
Self-Management Methods for Night Blindness:
There are a couple of ways of self-managing the symptoms of night blindness:
- Increase your visibility by regularly cleaning your car’s headlights and windscreen. Drive on slower lanes.
- If possible, avoid driving at night. You can ask a family member or friend to drive or even might consider hiring a taxi.
- Slow down and never rush during night. It would help in easy adjusting during night and would give more time to react during any hazard.
- Get prescription glasses for driving at night. An ophthalmologist might help in providing the best suitable glasses.
- Use sunglasses during daytime to avoid unnecessary exposure to sun rays. Excessive exposure to sun rays might also cause temporary night blindness.
- Avoid smoke and dust particles.
- Prefer glasses with an anti-glare coating. It helps in reducing strain to the eyes during day-to-day activities.
- Get your peripheral vision checked regularly to improve your night vision.
- Join a support group that keeps you motivated and inspired.
- Consume a well-balanced diet that has high vitamin A and zinc content. Having fruits, vegetables and whole foods with antioxidants help in preventing cataracts. Take vitamin
- A and zinc supplements to treat night blindness, but these must only be used in recommended amounts.
- Reduce stress and anxiety by practicing yoga and meditation.
- Avoid staring a single object for long and viewing directly into light sources.
- Practice eye exercises and movements to improve your night blindness. A doctor or ophthalmologist can help in teaching simple eye exercises.
Natural Ways to Cure Night Blindness
There are several ways to cure night blindness or nyctalopia naturally:
- Consuming Vitamin A-Rich Foods: Vegetables and fruits that have high vitamin A content help treat night blindness naturally. Such foods include fish, liver, dairy products, cereals, broccoli, squash, cantaloupe, and carrots. Fish is a rich source of omega-3 fatty acids and promotes night vision. Salmons, herring and sardines are excellent sources of docosahexaenoic acid (DHA) – an omega-3 fatty acid. DHA makes about 50% of the photoreceptor cells in the retina. Shellfish and oysters are also a good source of zinc and retinol. These help in maintaining overall eye health and enhance night vision.
- Wood Apple: Take around 10 gm of wood apple leaves. Grind these leaves with a few corns of black pepper in water. Add sugar to this mixture and consume twice daily. This helps in curing night blindness. Soak some leaves overnight and wash your eyes with this water the next morning.
- Alternanthera Sessilis: Chew about 3 to 4 petals of alternanthera sessilis flower early morning to cure night blindness.
- Fennel: Mix about half a teaspoon of powdered fennel in a glass of carrot juice. Consume this mixture daily to strengthen the optic nerves and cure nyctalopia.
- Holy Basil: Collect a few blackened holy basil leaves. Grind them to extract their juice. Use this juice as an eye drop before sleeping.
- Blueberries: These are a wonderful source of antioxidants. Perhaps, blueberries provide more antioxidants that any other fruit or vegetable. Consuming blueberries regularly is known to improve night vision.
- Bilberries: These are found in Europe and belongs to the family of blueberries. Bilberries help enhance the night vision due to anthocyanosides present in them. Anthocyanosides are flavonoids that help in the regeneration of rhodopsin, which is responsible for night vision.
- Eye Exercise: Rotate pupil of each eye right-left, up-down and in circular motions ten times at a time. Blinking eyes at a fast pace is also a great exercise.
Health Tip by Expert
Ensure that you consume vitamin A-rich foods every day to prevent night blindness or nyctalopia. Regular intake of red, yellow and green foods like as broccoli, mangoes, papaya, oranges, cantaloupes, bell peppers, lemons, sweet lime, pumpkin and spinach can significantly help you prevent or manage this eye condition.