Do you keep your eye drops for months in the refrigerator and use them whenever required? Well, the expiry date might be lying to you. Most individuals assume that checking the expiry date on the eye drops is sufficient to determine their safety for your delicate eyes. However, doctors emphasise that the expiry date printed on the packaging might not be enough. "Most eye drops should be discarded one month after opening, even if the bottle isn't empty and the printed expiry date is still far away. Preservative-free, single-use vials should be discarded within 24 hours of opening. Some brands recommend discarding right after use," says Dr. Shibal Bhartiya, Ophthalmologist, Glaucoma Surgeon, and Director of Ophthalmology at Marengo Asia Hospitals.

What exactly happens a month after opening an eye drop?

It is often recommended to discard a multi-dose eye drop bottle within 28 to 30 days of opening primarily because breaking the sterile seal exposes the liquid to air and physical contact, which drastically increases the risk of bacterial, fungal, and viral contamination.

Does this reduce the efficacy of the drops or cause any harmful effect?

"Both can happen. Once opened, the solution is exposed to air and the surrounding environment, and the tip can come into contact with eyelids or lashes. This introduces bacteria and lets the preservative system break down over time," Dr. Bhartiya explains.

"The active drug can become less potent, so the treatment works less well, and there is a risk of microbial contamination leading to eye infections such as conjunctivitis or keratitis, which in rare severe cases can threaten vision. Even though efficacy is an issue, contamination is what can actually harm you more," she elaborates.

"Glaucoma patients are particularly vulnerable to both mechanisms, since a contaminated or degraded bottle can mean their eye pressure isn't actually being controlled without them realising it," she adds.

What about the printed expiry date, how useful is that?

"The expiry date reflects the drug's stability and sterility in a sealed, unopened bottle under controlled storage conditions. It tells you the outer limit for using the bottle if it is never opened. Once the bottle is opened, the one-month rule (or 24 hours for single-use vials) takes over, regardless of what the printed expiry date says," clarifies Dr. Bhartiya.

A bonus tip

"A simple tip I give all my patients: Look at the expiry date on the bottle BEFORE opening it. Not after that. Write down the date of opening your eye drops bottle on the bottle itself, and discard it one month after that date because that is the expiry date for an open bottle. Don't rely on your memory for this," she recommends.

Eye drop rules to follow

  • Write the date: Use a permanent marker to record the exact opening date right on the bottle.
  • Avoid contact: Never let the tip of the bottle touch your eye, skin, or any other surface.
  • Check for preservative-free drops: If you use single-use single-dose vials without preservatives, discard them within 24 hours of opening rather than 30 days.

Remember, eye drops are not any regular medicine. Careful use is non-negotiable for healthy eyesight.



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