Night blindness
Retinol is an essential component of the pigment rhodopsin (visual purple) on which vision in dim light depends. Hence lack of retinol may result in impairment of 'dark adaptation'. Night blindness is common in poor people living in underdeveloped countries and it can occur in the malabsorption syndrome in affluent countries. In case of children parent may notice that the child stumbles in dim light.
Xerophthalmia
The sebaceous glands and hair follicles of the skin and the tear glands of the eye become blocked with horny plugs of keratin so that their secretions diminish. The lack of tears and the heaping up of epithelium on the scleral conjunctiva and cornea produces Xerophthalmia. Xerophthalmia means dry eye.
Bitot's spots
These are triangular, foamy, rough and raised patches seen on bulbar conjunctiva not interfering with the vision. These are generally bi-lateral. If more than 2% of children of ages 0-5years show bitot's spots with conjunctival xerosis it should be regarded as a criterion for community diagnosis of Xerophthalmia and vitamin A deficiency.
Corneal Xerosis
Cornea becomes dry and hazy like ground glass.
Keratomalacia
It consists of softening of the entire thickness of a part of or whole of cornea. If not treated then it is a grave medical emergency. The process is rapid and may lead to necrosis, ulceration and destruction of the eye ball. It is reported that in India there are 4.5 million blind people of these one in every four is due to vitamin A deficiency.
Retinol is an essential component of the pigment rhodopsin (visual purple) on which vision in dim light depends. Hence lack of retinol may result in impairment of 'dark adaptation'. Night blindness is common in poor people living in underdeveloped countries and it can occur in the malabsorption syndrome in affluent countries. In case of children parent may notice that the child stumbles in dim light.
Xerophthalmia
The sebaceous glands and hair follicles of the skin and the tear glands of the eye become blocked with horny plugs of keratin so that their secretions diminish. The lack of tears and the heaping up of epithelium on the scleral conjunctiva and cornea produces Xerophthalmia. Xerophthalmia means dry eye.
Bitot's spots
These are triangular, foamy, rough and raised patches seen on bulbar conjunctiva not interfering with the vision. These are generally bi-lateral. If more than 2% of children of ages 0-5years show bitot's spots with conjunctival xerosis it should be regarded as a criterion for community diagnosis of Xerophthalmia and vitamin A deficiency.
Corneal Xerosis
Cornea becomes dry and hazy like ground glass.
Keratomalacia
It consists of softening of the entire thickness of a part of or whole of cornea. If not treated then it is a grave medical emergency. The process is rapid and may lead to necrosis, ulceration and destruction of the eye ball. It is reported that in India there are 4.5 million blind people of these one in every four is due to vitamin A deficiency.
