How long can you really use eye drops after opening them?

This matters because different types of eye drops come in different packaging. Some preservative-free drops come in single-use vials that must be discarded after use. Others come in specially designed bottles that may remain usable for longer.

“Patients should therefore check the label or package insert rather than simply following the one-month rule,” he added.

Doctors on the right way to use an eye drop (Photo: Magnific)

What happens if you use an eye drop for too long?

“Once a bottle is opened multiple times, there could be microorganisms entering the bottle, especially if the bottle tip touches your eye, eyelashes, fingers or another surface,” said Dr Bhasin.

Using contaminated drops can potentially result in infections and inflammation. “Contaminated drops can lead to conjunctivitis, corneal infection or inflammation,” he explained.

While conjunctivitis may be relatively mild in many cases, infection involving the cornea can be more serious. “In severe cases, especially when the cornea is involved, vision may be threatened by infection,” Dr Bhasin warned.

Which symptoms should you not ignore?

Dr Bhasin advises paying attention to redness, pain, discharge, swelling, light sensitivity or blurred vision. These symptoms can have several causes, but they warrant medical attention rather than self-treatment with an old or potentially contaminated bottle.

What are the biggest mistakes people make with eye drops?

“Common mistakes include touching the dropper tip, using someone else’s eye drops, not putting the cap back on the bottle, storing the bottle in too much heat or sunlight, and using a bottle far past the recommended discard date,” said Dr Bhasin.

A few simple habits can significantly reduce the risk:

* Wash your hands before applying eye drops.
* Don’t let the dropper tip touch your eye, eyelashes or skin.
* Replace the cap immediately after use.
* Store the bottle according to the manufacturer’s instructions, away from excessive heat or sunlight where advised.
* Never share eye drops with another person.
* Write the date you opened the bottle on its label so you know when it needs to be discarded.

“It is also helpful to write the date of opening on the bottle, which makes it easier to remember when it should be thrown away,” Dr Bhasin said.