What is xerophthalmia?
Xerophthalmia is a progressive eye disease caused by vitamin A deficiency. Lack of vitamin A can dry out your tear ducts and eyes. Xerophthalmia can develop into night blindness or more serious damage to your cornea, the outer layer of your eye. This damage may take the form of white spots on your eyes and ulcers on your corneas. Xerophthalmia usually can be reversed with vitamin A therapy.
Read on to learn the symptoms of and risks for this condition, and what treatment options are available.
The symptoms of xerophthalmia start out mild, and then get progressively worse if a vitamin A deficiency isn’t treated. If you have this condition, the thin lining of your eyelid and eyeball, called the conjunctiva, dries out, thickens, and begins to wrinkle. That drying out and wrinkling causes various symptoms.
Night blindness is an early symptom. This is an inability to see in dim light. The World Health Organization and public health workers have used number of cases of night blindness as a gauge of vitamin A deficiency in a population.
As xerophthalmia progresses, lesions form on your cornea. These deposits of tissue are called Bitot’s spots. You can also get corneal ulcers. In the latest stages of the condition, part or all of your cornea liquefies. This eventually leads to blindness.
Xerophthalmia is caused by a lack of vitamin A. Your body doesn’t produce vitamin A on its own. Instead, you have to get vitamin A from the foods you eat. Vitamin A is essential for vision because it’s an element of the protein that absorbs light in the receptors in your retina.
Vitamin A is also important for the function and maintenance of your heart, lungs, kidneys, and other organs.
Xerophthalmia is rare in the United States, United Kingdom, and other developed countries. It’s still seen in developing countries where people may have limited access to animal products, however.
Vitamin A is also known as retinol. It’s a fat-soluble substance found in animal products like:
- fish liver
- dairy products
It’s also possible to get vitamin A from vegetable sources in the form of beta carotenes. Beta carotenes are converted into retinol in your gut. But this process is inefficient as a vitamin A source compared with eating animal products. Sources of beta carotenes include:
- green leafy vegetables
- yellow and orange fruits and vegetables
- red palm oil
Xerophthalmia is rare in the United States: There are only isolated clinical reports of the disease, according to Dr. Alfred Sommer, a professor at the Johns Hopkins Bloomberg School of Public Health and an international expert on vitamin A deficiency.
Vitamin A deficiency and xerophthalmia are a major public health problem in the developing world, affecting millions of women and children. It’s a leading cause of blindness in children. A 2002 study found that worldwide:
- about 4.4 million preschool children had xerophthalmia
- more than 6 million women develop night blindness during pregnancy annually
The major risk for xerophthalmia is poverty and lack of adequate diet, especially a lack of animal products. Infants and children are at greater risk. The younger the child, the more severe the effects of vitamin A deficiency.
Children require a lot of vitamin A in order to grow. Vitamin A deficiency also affects the ability to survive common childhood infections and diseases, such as diarrhea, measles, and respiratory infections.
Other risk factors affect a much smaller number of people in the United States and other countries. The following are risk factors because they affect a person’s ability to absorb vitamin A:
- cystic fibrosis
- diseases such as celiac disease that limit the absorption of nutrients
- liver disease, such as cirrhosis
- chronic diarrhea
- radioiodine treatment for thyroid cancer, which may produce nonpermanent symptoms of xerophthalmia
How much vitamin A do you need?
According to the National Institutes of Health (NIH), recommended daily allowances for vitamin A differ depending on your age and, in some cases, gender.
|0–6 months||400 mcg||400 mcg|
|7–12 months||500 mcg||500 mcg|
|1–3 years||300 mcg||300 mcg|
|4–8 years||400 mcg||400 mcg|
|9–13 years||600 mcg||600 mcg|
|14 years and older||900 mcg||700 mcg|
The NIH gives separate recommendations for pregnant or breast-feeding women.
|14–18 years||750 mcg||1,200 mcg|
|19–50 years||770 mcg||1,300 mcg|
These recommendations are for people who are healthy and well-nourished. Your doctor may make different recommendations if you have a medical condition or a vitamin deficiency.
Your doctor will do a physical examination and ask you questions about your symptoms and diet.
If you have night blindness, your doctor may start you on vitamin A therapy, even before doing blood tests.
Sometimes corneal ulcers of xerophthalmia are mistaken for bacterial infections. As a result, your doctor may prescribe an antibiotic. Further testing for vitamin A deficiency may be needed.
Vitamin A supplementation is the immediate treatment for xerophthalmia. Vitamin A can be taken by mouth or injected. The dose varies according to your age and general health condition.
In more advanced cases where the cornea is damaged, you may receive antibiotics to prevent secondary infections. You may need to keep your eye covered to protect it until the lesion heals.
Vitamin A supplements can quickly reverse symptoms of xerophthalmia and help protect children from dying of other childhood diseases.
Vitamin A supplements are given preventively in areas where xerophthalmia is a known problem. This is a low-cost way to prevent human suffering and deaths. A
Nutrition education can be important in helping people make the best use of their food resources. Fortifying commercial foods with vitamin A also helps reduce vitamin A deficiency. Some foods that may be fortified include:
- oils and fats
Another possible source of vitamin A is golden rice, which is genetically engineered to contain beta carotene. It has been opposed by groups that are against any genetic modification of food.
Xerophthalmia improves quickly with vitamin A supplements. In very advanced cases, scarring may remain and impair vision. In the worst cases, permanent blindness may occur.
Vitamin A deficiency and xerophthalmia remain a significant public health problem in the developing world and in areas of war or natural disasters. The availability and affordability of an adequate diet, including animal products and green leafy vegetables, is key.
If you or your child are at risk for vitamin A deficiency, talk to your doctor about taking vitamin A supplements. Also, vary your diet as much as possible to include animal products, and vegetables and fruits with beta carotene.