A lack of Vitamin A in one’s diet can have serious ramifications on vision. Many foods such as fish liver oils, carrots, pumpkins, sweet potatoes, cantaloupes, liver, fortified milk, butter and eggs contain Vitamin A. An individual lacking in such nutrients can end up with Vitamin A deficiency.
The eye produces some pigments for the photoreceptor cells so that the retina can function efficiently. Vitamin A plays a critical role in the production of these pigments. Without Vitamin A, the eye will stop producing the pigments which results in night blindness.
Vitamin A is also critical in nourishing other parts of the eye. One such component is the cornea, the transparent tissue that covers the front part of the eye. Vitamin A is necessary to keep the eye adequately lubricated.
It is estimated that almost half a million children worldwide become blind as a result of Vitamin A deficiency. Vitamin A is the leading cause of preventable blindness in children. About 250,000 of these children lose their lives within a year after they lose their vision.
Lack of Vitamin A in pregnant women can result in night blindness. The deficiency may also cause maternal mortality.
Also Known As
Causes and Risk Factors
The following are the causes of Vitamin A deficiency:
- Surgery on the intestine or pancreas
- Blocked bile ducts and certain pancreatic disorders
- Malnutrition or a prolonged lack of a properly balanced diet
- Malabsorptive conditions and disorders which interfere with vitamin A metabolism. For instance, alcoholism and chronic liver diseases can impair Vitamin A metabolism
Vitamin A deficiency is very rare in developed nations. The few cases that occur may be caused by the following:
- Bad self-imposed dietary practices
- Chronic alcoholism and liver cirrhosis
- The effects of bowel resection and bariatric surgeries
- Cystic fibrosis which results in fat malabsorption leading to fat-soluble vitamin deficiency
Risk factors include:
- Individuals living in the developing world such as Southeast Asia and Africa
- Pregnant women and children who reside in developing countries
Signs & Symptoms
The following signs and symptoms can be indicative of Vitamin A deficiency:
- Vision loss and blindness are the main symptoms.
- The appearance of corneal ulcers which leads to vision loss.
- The eyes, skin and other tissues can become dry and damaged.
- Night blindness where someone does not see in the dark but can see well with enough light.
- Xerophthalmic fundus may develop. It is a rare abnormality where yellow-white spots can be spotted on the retina.
- Xerophthalmia, a condition in which the conjunctiva dries out. The conjunctiva is the covering on the white part of the eye and helps to lubricate the eye. Bitot's spots may form as a result of the dryness. They are foamy, gray, triangular spots on the conjunctiva.
The eye care professional may do the following to diagnose Vitamin A deficiency that affects the eye:
- A review of an individual’s medical history
- Checking to see how the pupils respond to light
- Blood test to measure how much of Vitamin A is in the blood
- Relief of symptoms when an individual takes vitamin A supplements
- A visual acuity test to check how far one can see from a chart placed a distance away
- Electroretinography can test for Vitamin A deficiency in individuals experiencing night blindness
Treatment of Vitamin A deficiency aims to increase the amount of Vitamin A in the body.
Xerophthalmia is a medical emergency and will immediately be treated with a high dosage of Vitamin A supplements. The eye doctor recommends Vitamin A supplements depending on the age of the child. The following is WHOs standard doses according to the patient’s age:
- Children aged one year and above receive 200,000 IU of the dose immediately and then another dose the following day. The child will receive an additional dose after two weeks to help with liver reserves
- Children from six months to a year need half the dosage
- Children less than six months old need a quarter of the dosage
Taking the recommended dosage of Vitamin A supplements can reverse night blindness. The supplements can also lubricate the eye again.
If not treated, Vitamin A deficiency can lead to scarring from corneal ulcers which can result in irreversible loss of vision.
Also, if Vitamin A deficiency is left untreated, the growth and development of children may slow down and even lead to death.
The children’s immunity system does not function well with Vitamin A deficiency giving rise to infections and diseases like measles, diarrhea and malaria. These diseases can lead to death.
There is an increased risk of getting certain cancers in a patient on beta-carotene supplements.
Too much of Vitamin A supplements may lead to toxicity. It can cause loss of hair, weakened bones, cracked lips and headaches. There is also a possibility of idiopathic intracranial hypertension, i.e., increased pressure within the skull.
Some international organizations are working towards reducing Vitamin A deficiency in populations at risk. These organizations seek to promote the prevention of Vitamin A deficiency through education on adequate diet and provision of vitamin supplements.
Patients are encouraged to consume carotenoids, pigments in fruits and vegetables. Carotenoids, cooked or homogenized, are slowly converted to Vitamin A. The best sources of carotenoids include dark, green, yellow, and orange vegetables. Yellow and orange fruits are also an excellent source. They include papayas, oranges, carrots, squash and pumpkin.
At-risk children in developing regions should take vitamin A supplements.