Eye Drop Bottle with Galaxy Inside

Do Your Eye Drops Expire? A Deep Dive into Shelf Life and Safety

Beau Callahan in Health & Wellness November 2025 • 3 min read.

"Uncover the facts about how long your diagnostic eye drops really last and what the risks are of using them past their prime."

When was the last time you checked the expiration date on your eye drops? If you're like most people, it's probably not something you think about often. However, using expired eye drops could potentially lead to eye infections. To avoid contamination, most pharmaceutical companies suggest discarding ophthalmic drugs 28 days after opening, but recent research suggests this may be overly cautious.

A study published in Optometry and Vision Science has shed light on the shelf life and efficacy of diagnostic eye drops. Researchers aimed to evaluate the preservation period and effectiveness of common ophthalmic preparations, including proparacaine hydrochloride, tropicamide, phenylephrine hydrochloride, and cyclopentolate hydrochloride.

The study challenges conventional wisdom, suggesting that in controlled clinical settings, diagnostic eye drops may be safe and effective for much longer than the standard 28-day period. Let's dive into the details of this research and explore what it means for your eye health.

What the Study Revealed About Eye Drop Contamination

The study involved 38 primary eye care students who used 25 bottles of each diagnostic eye drop over a seven-month period. Researchers repeatedly analyzed bacterial contamination using agar plates and nutrient broth at various intervals. Participants also recorded the number of times the bottles contacted biological tissues.

During the study, participants administered a significant number of drops:

4,971 drops of proparacaine
3,219 drops each of tropicamide and phenylephrine
1,896 drops of cyclopentolate

Despite these numbers and 226 reported contacts between bottles and biological tissues, the study found no bacterial or fungal contamination in any of the tested eye drop bottles. Additionally, no patient reported any eye infections within two weeks after the eye drop instillation.

The Bottom Line: Practical Advice for Eye Drop Usage

While the study suggests that diagnostic eye drops can be used longer than 28 days in a controlled environment, it’s crucial to remember that these results may not apply to individual use. Factors like storage conditions and personal hygiene play a significant role in preventing contamination. Always consult with your eye care professional for personalized advice, and be vigilant about any signs of eye irritation or infection.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1097/opx.0000000000001288, Alternate LINK

Title: Shelf Life And Efficacy Of Diagnostic Eye Drops

Subject: Optometry

Journal: Optometry and Vision Science

Publisher: Ovid Technologies (Wolters Kluwer Health)

Authors: Jean-Marie Hanssens, Carolina Quintana-Giraldo, Sandrine Jacques, Nohade El-Zoghbi, Vanessa Lampasona, Camille Langevin, Jean-François Bouchard

Published: 2018-10-01

Everything You Need To Know

What is the standard recommendation for how long eye drops can be used after opening, and what does recent research suggest about this?

Pharmaceutical companies typically recommend discarding ophthalmic drugs 28 days after opening to avoid contamination. However, a study in Optometry and Vision Science suggests that in controlled clinical settings, diagnostic eye drops may remain safe and effective for longer. This discrepancy highlights the need to consider factors like storage conditions and personal hygiene, which are critical in preventing contamination in individual use.

Which specific diagnostic eye drops were examined in the Optometry and Vision Science study, and what methods were used to assess their contamination?

The study evaluated the preservation period and effectiveness of common ophthalmic preparations, specifically proparacaine hydrochloride, tropicamide, phenylephrine hydrochloride, and cyclopentolate hydrochloride. Researchers analyzed bacterial contamination using agar plates and nutrient broth over a seven-month period. The study also tracked the number of times the bottles contacted biological tissues to assess potential contamination routes.

How many participants were involved in the study, and what quantities of proparacaine, tropicamide, phenylephrine and cyclopentolate were administered during the research?

The study involved 38 primary eye care students who used 25 bottles of each diagnostic eye drop over seven months. They administered 4,971 drops of proparacaine, 3,219 drops each of tropicamide and phenylephrine, and 1,896 drops of cyclopentolate. Despite 226 reported contacts between bottles and biological tissues, no bacterial or fungal contamination was found, and no patient reported any eye infections within two weeks of instillation.

Even if diagnostic eye drops can last longer than expected, what are the crucial factors to keep in mind for safe individual use to prevent bacterial contamination?

While the study showed no contamination in a controlled setting, it's essential to recognize that individual usage conditions vary widely. Factors such as storage temperature, humidity, and the user's hygiene practices can significantly impact the risk of contamination. For instance, frequent touching of the dropper tip to the eye or storing the bottle in a warm, humid environment could introduce bacteria, negating the study's findings.

Did the study's findings apply to all kinds of eye drops, or were specific ophthalmic drugs examined, and what other elements weren't evaluated?

The study focused specifically on proparacaine hydrochloride, tropicamide, phenylephrine hydrochloride, and cyclopentolate hydrochloride in a controlled clinical setting. The results may not be generalizable to all types of eye drops, especially those with different formulations or preservatives. Furthermore, the study did not assess the impact of preservatives on the ocular surface over extended periods, which is crucial for long-term safety considerations.