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Why you shouldn't use eye drops that are not meant for contact lenses

With so many options for dry eyes to itchy eyes and everything in-between, things can get confusing. An eye expert helps you choose what’s right for you – whether or not you do use contacts.

If you’ve shopped for eye drops in a pharmacy before, you’d know that the options are, well, eye-opening. There are drops for dry eyes, red eyes, itchy eyes, computer eyes, infected eyes … the list goes on. 

While it is often quite straightforward which eye drops to get (a moistening one for dry eyes, for example), there are also instances when you might feel a little uncertain. For instance, if you’re a contact lens user, is it okay to use drops not formulated specifically for lens wear? Can you use that bottle meant for red eyes to soothe a case of itchiness?


We’ll get to these burning questions later. First of all, one should check the bottle’s expiry date and whether these drops contain preservatives.

It goes without saying that you shouldn’t use an expired product, even if it’s unopened. “Once past the expiry date, the active ingredients and preservatives may start to degrade. At best, this will cause the eye drops to be less effective or completely ineffective.

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"At worst, using expired eye drops may cause further irritation or even harm to the eyes,” said Dr James Pan, senior consultant ophthalmologist at Healthway Medical’s Nobel Eye and Vision Centre.

If you have particularly sensitive eyes, you should also check the ingredient label for preservatives, he added.

“Most eye drops contain preservatives that prevent bacterial growth, so they can last longer once opened,” said Dr Pan. The preservatives may also worsen a pre-existing eye irritation that causes red eye in the first place.

Hence, preservative-free eye drops may be better for those with sensitive eyes, he said. “When in doubt about the most suitable eye drops to treat your condition, it is best to consult a doctor,” Dr Pan added.

(Photo: Pixabay/Jill Fulton)


Once you’ve established the eye drops you’re looking at is safe to use, figure out if they’re right for your eye problem. That’s because eye drop formulations aren’t simply just saline solutions.

For instance, drops meant to neutralise red eyes may not treat the underlying cause if an allergy is behind the issue. Also, you shouldn't use eye drops not formulated for contact lens users if you have them on.

Here’s a look at what the various eye drops are and how they work:


Some brands label them as lubricating eye drops or artificial tears. These drops usually contain carboxymethylcellulose and glycerin to keep your eyes moist, and sodium hyaluronate to prevent them from drying out, said Dr Pan.

“Some brands of hydrating eye drops may contain mineral oils, which provides an extra layer of thickness to the lubricants and gives the eye drops a more oily texture.”

Contact lens wearers are likely to require the extra hydration from eye drops as their lenses impede oxygen flow and moisture from reaching the corneas. But can they use regular drops?

Better not. “It is best for contact lens wearers to only use eye drops that have been indicated as safe for contact lenses,” said Dr Pan.

The reason lies with the compatibility of the eye drops’ ingredients; for instance, the preservatives in some hydrating eye drops and chemicals in anti-redness drops may stick to the contact lenses, “causing irritation and possibly, negatively affecting eye health in the long term”, he said.

In addition, contact lenses retain certain components used in the eye drops and expose the eye to them over longer periods, cautioned Dr Pan. “This is less of a problem with daily contact lenses that are discarded daily, but as a precaution, it is always recommended for contact lens wearers to use only eye drops that are safe for use with contact lenses.”

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Also known as anti-redness eye drops, they usually contain vasoconstrictors – chemicals that shrink the blood vessels on the ocular surface (the white part of the eye) to reduce the red eye effect, said Dr Pan. “Some anti-redness eye drops may also contain anti-histamines.”

However, it is important to note that while anti-redness eye drops may reduce the redness, they do not actually eliminate the cause of the irritation, said Dr Pan.

“Once the effect of the eye drops wears off, the redness will return. This may lead to a cycle of dependency, and the redness of the eyes may worsen over time when the eye drops are not used.”

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Makeup artists for celebrities swear by their “waking up” effect on the peepers. These eye drops from Japan feel like rubbing chilli on your eyes at first but soon give way to a cooling sensation that users say is refreshing.

Some of these formulations contain the red-eye relieving tetrahydrozoline or the decongestant naphazoline, while others also have zinc sulfate as an astringent. 

“Tired eyes may be caused by dry eyes or swelling of the eyes, and eye drops that are marketed as a solution for tired eyes are often simply anti-redness eye drops or hydrating eye drops,” cautioned Dr Pan.


The main ingredient in anti-allergy eye drops are antihistamines, said Dr Pan. “The release of histamines during an allergic reaction is what causes symptoms such as itchy eyes, or redness and swelling of the eyes. The anti-histamines in anti-allergy eye drops will block these histamines, thus relieving the allergy symptoms.”

Source: CNA/bk