Vitamin A eye drops are made to help the body absorb vitamin A through the eyes and to help a range of eye problems. The eyes naturally have vitamin A in the tear film, but a diet lacking in vitamin A may lead to this film disappearing, which causes dryness and many other problems. Beta-carotene is often used in vitamin A eye drops, even though it must convert into vitamin A to be useful. Beyond helping dry eyes, vitamin A eye drops also help glaucoma, cataracts, blurred vision and conjunctivitis. While the extra vitamin A will be welcomed by most bodies and is normally very healthy, some people can get too much vitamin A from these eye drops, which can cause even worse problems than a vitamin A deficiency.

Eyes naturally have vitamin A, which is why vitamin A eye drops can be so beneficial — they add the extra vitamins to the eyes if a person does not get enough of the vitamin in his diet. Vitamin A in the eyes can be found in the tear film and helps produce mucus for tears, which keeps out diseases. This means that using eye drops with vitamin A may protect a person's eyes from toxins, free radicals and allergens.

The supplement in vitamin A eye drops that gives it the vitamin boost can be different forms of vitamin A, or it may be beta-carotene. For many people, it will not matter if beta-carotene is used, because even though it is a precursor to vitamin A and not the vitamin itself, the body can easily convert the beta-carotene into vitamin A. If the user has an underactive thyroid, though, he or she will be unable to convert the beta-carotene and should look for eye drops made with retinol instead.

While eye drops are primarily supposed to stop eye dryness, vitamin A eye drops also may be able to treat a few other problems. The tear film requires vitamin A, so these drops are able to help with blurred vision. As a vitamin, these eye drops can help heal or treat eye problems such as cataracts, conjunctivitis and glaucoma.

In very rare instances, users can actually become sick from vitamin A eye drops because of vitamin A toxicity. The problems associated with toxicity from such eye drops are liver problems, reduced bone density and central nervous system disorders. Unless the user has trouble processing vitamin A, this only occurs if the vitamin A eye drops are used in conjunction with powerful vitamin A supplements over an extended amount of time.