By The Eye PracticePublished On: 19 June 20173.6 min read

Everyone knows the causes of red eyes include allergies and eye infections, but did you know that eye drops play a big role in causing this frustrating condition?

It sounds like a contradiction in terms, but eye drops cause more red eyes than practically any other cause. Read on for the biggest culprits:

Preservatives

These are added to eye drops of all sorts to prolong their shelf life and protect against cross contamination. But they’re toxic to living cells – including yours. Some eye drops are available in unit dose (especially artificial tears) and many others can be specially formulated in preservative-free forms by a compounding pharmacy. It’s a bit more trouble and expense, but if you suffer from chronic red eyes, it could be worth it.

No time to read the whole article? Download our Quick Guide to Treatment for Red Eyes here.

Vaso-constrictors

These really are the wolf in sheep’s clothing! The whole idea of drops like Visine and Murine is to make your eyes white (not even redder) so what goes wrong? Vasoconstrictors cause the blood vessels in the eye to narrow, so the eyes initially look whiter. This is why these drops are occasionally recommended for one-off special event such as a photo shoot or public appearance. But if used for longer, they cause the blood vessels to adapt and as soon as you stop using them, the vessels dilate, making the eyes redder than ever. They can be addictive and require weaning off for long-term users. Save them for your wedding day!

Antibiotics

These are vitally important to use if you have a bacterial infection in your eye or if you are recovering from an eye operation (such as cataract surgery or laser eye surgery). They kill a broad spectrum of bacteria and protect the eye from invasion by nasty microbes. They can be harsh on the eye’s delicate surface, but that’s not a reason to discontinue them. If your eyes become red during your recovery from surgery, it’s time to see your surgeon for review.

Artificial tears

Wait. What? Artificial tears can make your eyes red? Redness is a hallmark sign of dry eyes. In fact, for a lot of people suffering from dry eyes, the redness causes more distress than the discomfort. So, you reach for the artificial tears. And they bring some relief, and the next thing you know, you’re using them 6 times a day. The problem with this is that it can do more harm than good. Constantly adding these drops to your eyes can flush out your own natural tear film, that is designed to prevent evaporation of the watery tears produced in your lacrimal gland. Unless you have Sjogren Syndrome, an autoimmune disease that affects the lacrimal tear glands and salivary glands, you shouldn’t need to use artificial tears more than once or twice a day. It’s a bit like adding moisturiser to your skin because you work in a dry office environment. If you overdo it, your skin won’t thank you.

Chlorsig

This over-the-counter antibiotic eye drop (also called Chloramphenicol) is a prime culprit when it comes to red eyes. It is only beneficial to eyes that have a bacterial conjunctivitis. All other forms of conjunctivitis (including viral, allergic and seasonal) are not helped at all by using Chlorsig. In fact, most conjunctivitis is not bacterial and will not respond to Chlorsig. Instead, adding this preserved eye drop to an already compromised eye can make it worse. Viral infections that should have cleared up in less than a week can drag on for weeks or longer because Chloramphenicol is being added several times a day. If you or your child develops conjunctivitis, don’t head for the pharmacy. Talk instead to your therapeutically-endorsed optometrist, who will be able to examine your eyes and recommend the appropriate therapy. Chlorsig must absolutely not be used to treat any contact lens related eye infection – a very serious disease that can result in permanent scarring if inappropriately treated. If you wear contact lenses and develop a painful, red eye, see your optometrist within a day and if they are not available, head to your local eye hospital or emergency department.