Xerophthalmia: Features, Treatment and Prevention

In this article we will discuss about the Xerophthalmia:- 1. Meaning of Xerophthalmia 2. Clinical Features of Xerophthalmia 3. Treatment 4. Prevention.

Meaning of Xerophthalmia:

Xerophthalmia (Greek xeros, dry; ophthalmos, eye) is a condition caused by vitamin A deficiency. In its milk form it is confined to the conjunctiva which is very common in many countries.

There is danger of corneal ulceration when it spreads to the cornea and a permanent defect in vision. In severe cases, there is softening of the cornea, keratomalacia, which, if not immediately treated, soon leads to permanent blindness. Keratomalacia is associated in young children with protein-energy malnutri­tion.

Xerophthalmia arises when the diet contains practically no whole milk and butter and very lim­ited amounts of fresh vegetables and fruit and so lacks both retinol and carotenes. Xerophthalmia and keratomalacia both occur in the first year of life amongst artificially fed infants but are rare amongst the breast fed.

Children in poorly nour­ished communities are born to mothers who have had small intakes of vitamin A and consequently their liver stores are small at birth.

Clinical Features of Xerophthalmia:

a. The bulbar conjunctiva is dry, thickened, wrinkled and pigmented due to a failure to shed the epithelial cells, and conse­quent keratinization. The pigmentation gives the conjuctiva a peculiar ‘smoky’ appearance. The pigment is diffused and especially marked in the inter-palpebral fissure.

Dryness, thickening and pigmen­tation characteristic of the condition are also caused by long periods of exposure to glare, dust and infections. This is com­mon in older children and adults in the tropics.

b. When dryness spreads to the cornea, this takes on a dull, hazy, lack-lustre appear­ance. This is due to the keratinization which is the result of Vitamin A deficiency on all epithelial surface. The cornea often becomes insensitive to touch with a wisp of cotton wool. Corneal ulceration may occur from many causes and be unrelated to Vitamin A deficiency.

The characteris­tic feature is a loss of substance (erosion) of a part or the whole of the corneal thick­ness. Unless there is secondary infection, there are no signs of inflammation. The lesion only heals by scarring. Corneal xero­sis may progress suddenly and rapidly to keratomalacia.

c. Softening and dissolution of the cornea follow and are known as colliquative necrosis. This presents a grave emergency. When the process involves only part of the cornea, there is ulceration but the in­flammatory reaction is mild.

If the process is not stopped by treatment, perforation of the cornea leads to prolapse of the iris, extrusion of the lens and infection of the whole eyeball. The chances of saving any useful vision are slight. Healing results in scarring of the whole eye and frequently in total blindness. The retinol content of the plasma is below 200 µg/I, the lower limit of the range.

d. Night blindness is an early symptom of vitamin A deficiency and is often present without any signs of xerophthalmia.

e. The prolonged Vitamin A deficiency in school children or young adults may show lesions appearing as spots, either white or yellow, scattered along the sides of the blood vessels. The spots may fuse and the lesions are most numerous on the periph­ery of the fundus and never appear on the macula.

f. Corneal scars are white, opaque patches on the cornea and the result of healing of an older ulcer. Vision may be seriously affected, depending on the size of the scars. There are other causes of corneal scars but Vitamin A deficiency is the most effective.

Treatment of Xerophthalmia:

a. Vitamin A in a dose of 30 mg of retinol (100.0001.U.) should be administered daily for three days immediately the diagnosis is made or strongly suspected. It is recom­mended that half the dose should be given orally in the form of halibut oil and half intramuscularly as water-miscible retinol palmitate. An oil solution should not be injected as the retinol is then absorbed very slowly from the injection site.

b. Cod liver should not be instilled directly into the eye. During convalescence 9 mg of retinol in the form of a fish liver oil orally is adequate. It is also most essential that the diet is satisfactory in regard to other nutrients.

c. Secondary bacterial infection should be treated by the use of antibiotics which are of great value. Local treatment of the eye will only be required provided the diag­nosis is present.

Prevention of Xerophthalmia:

a. Most cases occur in urban poor and rural peasants in under doctored areas, and keratomalacia develops without the chil­dren being seen by a doctor. Therefore, to prevent this, doctors, nurses and mid- wives, and other paramedical staffs asso­ciated with maternal and child health clin­ics should be trained.

b. Pregnant women should be advised to eat dark supplements rich in Vitamin A in pro­phylactic doses. This helps to build up stores of retinol in the fetal liver and should be continued during lactation. Mothers should be advised to include in the wean­ing foods dark green leafy vegetables or yellow and orange fruits, which are locally available, cheap and known to be good sources of β-carotene.

c. In blindness from keratomalacia single large prophylactic doses of retinol in oily solution are recommended. This is given as a capsule to be taken orally. The dose is safe and adverse effects are rare. All pro­phylactic programmes should be evalu­ated by periodic field surveys of the preva­lence of xerophthalmia.

d. Nutritional disorders of the eye are only one of several causes of blindness. There are more than ten million blind people in the world. Most of them are blind before the age of 5. Trachoma, a virus infection, is the most important eye disease in the world. It is common in children and, if un­treated, often causes progressive loss of vision and blindness.

Small pox often af­fect the eyes and is responsible for 1/5th of the blindness in India. Onchocercosis is caused by a filarial worm which is trans­ferred from man to man by flies. It causes nodules in the skin and thence microfilaria invade the eye which leads to blindness.

The disease commonly affects people who live besides river. In some villages, all the adult population are blind. Venereal dis­eases, congenital syphilis and gonococ­cal ophthalmia neonatorum are important causes of blindness in parts of the world where the maternity services are inad­equate or totally lacking.

Accidents in the home and at work are common causes of blindness. Many young children lose their sight in this way. Diabetes, cataract and glaucoma are important causes of blind­ness in elderly people. Vitamin A deficiency is thus one of the important causes of blindness and the most easily preventable.