Were you told as a child to eat your carrots because they would make you see better in the dark?

This is more than merely an old wives’ tale.

Night blindness, or poor vision in the dark, is usually a sign of deficiency of vitamin A, which carrots can help to replace.

This is because carrots are an excellent source of beta carotene, which the body converts into vitamin A.

It is a fact that a healthy, balanced diet has a role to play in maintaining good eyesight, with vitamin A holding the key to healing a number of eye disorders.

Beta carotene, which the body converts into Vitamin A, is found in yellow and orange coloured fruits and vegetables (apricots, mangoes, carrots, sweet potatoes and squashes) and in dark green, leafy vegetables such as spinach and kale.

In the developing world, vitamin A deficiency is the most common cause of blindness in people under the age of 21.

The first sign of this deficiency is usually night blindness - inability to adapt to low-light intensity.

A build-up of fluid pressure in the eye is known as glaucoma.

It is most common among people aged 40 and above and tends to run in families. Symptoms include blurred vision, a circle of light and difficulty seeing in the dark.

Glaucoma has been linked to a deficiency of thiamin, found in meat, fish, poultry, whole grains, pulses and nuts, and of vitamin A, which is abundant in liver and eggs, and also derived from orange-coloured plant foods that contain beta carotene.

Another common eye ailment is cataracts, which is a painless clouding in the eye and is common among the elderly, but can occur in younger people because of a rare metabolic defect.

It is believed that cataracts are the result of oxidation occurring in the lens of the eye, and vitamin C may help to protect against this type of damage.

Other studies indicate that riboflavin, found in milk, wholegrain cereals and yeast extract, may also offer some protection.

The ability of the eye to metabolise a sugar called galactose appears to decrease as we grow older.

This, combined with a high level of galactose in the blood, which occurs in the inherited condition known as galactosaemia, may also trigger the formation of cataracts.