Vision vitamins are the nutritional elements that enhance eye sight. These include vitamin A, B6, C, selenium, trace elements such as magnesium and zinc among other nutrients. A variety of food containing vitamins include, among others oranges, carrots, pumpkin and leafy vegetables. Having enough of these food sources in the diet protects one from getting certain eye diseases such as cataracts and macular degeneration.
We will look at vitamin A in detail and understand what it is that it does at cellular level. Research has revealed to us that this vitamin is very important in the synthesis of a pigment known as rhodopsin. This pigment is found in high amounts on the retina which acts as a screen on which images from the environment are formed. Adequate levels of rhodopsin are needed to help one see better in dim light.
The A vitamin is not a single unit as such but is composed of a group of hydrocarbons which are not saturated. These include retinoic acid, retinal, retinol and a number of vitamin A precursors (carotenoids). The most important among the pro vitamin A carotenoids is beta carotene. Retinal component combines with the protein opsin to form rhodopsin. The so formed light absorbing molecule is vital for both colour and low light (scotopic) vision.
Deficiency of vitamin A results in a number of eye conditions that vary in severity depending on the extent of involvement. It often occurs when there is reduced intake of provitamin A carotenoid containing foods such as vegetables, dairy and animals products and fruits. This is the commonest scenario and is also referred to as primary vitamin A deficiency.
Secondary deficiency is commonly the result of impaired absorption of lipids and decreased production and release of bile. The A vitamin is fat soluble and will therefore require that there are enough lipids for it to be adequately absorbed. Cigarette smoking and prolonged alcohol use are the other risk factors that have been identified as contributing to insufficiency of this vitamin.
One of the most initial manifestations of vitamin A deficiency is night blindness. This refers to impaired scotopic vision. With time, the condition may worsen and changes such as drying of the conjunctiva may occur. This happens because the normal tear secreting system is replaced by keratinisation. This is accompanied by formation of keratin plaques in the cornea which eventually gets eroded as more keratinisation leading to complete blindness.
The other vitamins play a relatively minor role. Vitamin C has antioxidant properties which help protect the eye from irradiation. It is also important in the maintenance of capillary integrity and normal pressure. The B6 vitamin maintains red cell structure and function and thus ensures that the retina functions optimally. Zinc takes part in the conversion of beta carotene to vitamin A.
The truth is that it is not possible to take all the vision vitamins on a daily basis. What is important is to ensure that one takes them as many times as possible within the week. Intake is determined by factors such as sex, age, pregnancy and lactation. Excessive of the vitamins may cause toxicity and due caution is, therefore, advised.
We will look at vitamin A in detail and understand what it is that it does at cellular level. Research has revealed to us that this vitamin is very important in the synthesis of a pigment known as rhodopsin. This pigment is found in high amounts on the retina which acts as a screen on which images from the environment are formed. Adequate levels of rhodopsin are needed to help one see better in dim light.
The A vitamin is not a single unit as such but is composed of a group of hydrocarbons which are not saturated. These include retinoic acid, retinal, retinol and a number of vitamin A precursors (carotenoids). The most important among the pro vitamin A carotenoids is beta carotene. Retinal component combines with the protein opsin to form rhodopsin. The so formed light absorbing molecule is vital for both colour and low light (scotopic) vision.
Deficiency of vitamin A results in a number of eye conditions that vary in severity depending on the extent of involvement. It often occurs when there is reduced intake of provitamin A carotenoid containing foods such as vegetables, dairy and animals products and fruits. This is the commonest scenario and is also referred to as primary vitamin A deficiency.
Secondary deficiency is commonly the result of impaired absorption of lipids and decreased production and release of bile. The A vitamin is fat soluble and will therefore require that there are enough lipids for it to be adequately absorbed. Cigarette smoking and prolonged alcohol use are the other risk factors that have been identified as contributing to insufficiency of this vitamin.
One of the most initial manifestations of vitamin A deficiency is night blindness. This refers to impaired scotopic vision. With time, the condition may worsen and changes such as drying of the conjunctiva may occur. This happens because the normal tear secreting system is replaced by keratinisation. This is accompanied by formation of keratin plaques in the cornea which eventually gets eroded as more keratinisation leading to complete blindness.
The other vitamins play a relatively minor role. Vitamin C has antioxidant properties which help protect the eye from irradiation. It is also important in the maintenance of capillary integrity and normal pressure. The B6 vitamin maintains red cell structure and function and thus ensures that the retina functions optimally. Zinc takes part in the conversion of beta carotene to vitamin A.
The truth is that it is not possible to take all the vision vitamins on a daily basis. What is important is to ensure that one takes them as many times as possible within the week. Intake is determined by factors such as sex, age, pregnancy and lactation. Excessive of the vitamins may cause toxicity and due caution is, therefore, advised.
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