Anyway, once upon a time, an Australian study called the Blue Mountains eye study (which was carried out in the late 1990s), examined the link between increased vitamin A intake and deteriorating night vision in older people. The study shown that people who reported having poor eyesight, ate more carrots to improve their eyesight. But it didn't help at all.
The vision loss reported by the people in the Blue Mountains eye study was caused mainly by age-related reasons, not a dietary problem, which explains why their eyesight didn't improve regardless of how many carrots they ate.
Some clever man called Professor Algis Vingrys who went to a posh eye university, says "no amount of carrots will improve your eyesight if you already have a well balanced diet."
"A diet with sufficient vitamin A, iron and other pro-vitamins (substances that our bodies can convert into vitamins) is vital for eye health.
There are two types of vitamin A: retinoids and carotenoids.
Retinoids are a lipid form of vitamin A found in liver, fish oils containing liver (eg cod-liver oil) and butter. Eating large amounts of these substances can give you an overdose of vitamin A and lead to toxicity, or worse, promote some forms of cancer.
Carotenoids are pro-vitamins your body converts into vitamin A. Carrots, broccoli, sweet potatoes, pumpkin and dark-green leafy vegetables all contain beta-carotene, a potent carotenoid. But how much gets converted depends on how much vitamin A you already have in your body – in other words, your body doesn't make vitamin A if you don't need it.
A diet deficient in vitamin A can lead to night blindness and other eye problems. Reduced night vision is one of the earliest signs of vitamin A deficiency although people rarely complain of night blindness until it becomes really severe.
But vitamin A deficiency is rare in Australia. Most of us eat a reasonably balanced diet, although pregnant women, those who don't eat a varied nutritious diet and some people with bowel disease may need to see their doctor if they feel they are at risk."
So there's your answer... Eating carrots and other foods with vitamin A could possibly improve night vision if you are lacking in vitamin A, although zinc and iron is also needed, but eating them will not help if your diet is already balanced.