When eye drops expire, their effectiveness can diminish and there is a possibility of bacterial contamination, which can increase your risk of developing an eye infection. This blog will explore what eye drops are used for, what is in them, why they expire, and why you should discard them upon expiration.
What Are Eye Drops and What Is In Them?
Eye drops serve many purposes, including: treatment for glaucoma, treating infection, reducing inflammation, and to keep dry eyes lubricated.
Types of Eye Drops
Eye drops are ophthalmic solutions used to treat various eye conditions and symptoms. Here are some of the common types of eye drops and their purposes:
- Artificial Tears: These lubricating eye drops relieve dryness and discomfort caused by insufficient tear production or poor tear quality.
- Allergy eye drops: These drops contain antihistamines and/or mast cell stabilizers to relieve itching and redness associated with eye allergies.
- Antibiotic eye drops: These are prescribed to treat bacterial eye infections, such as bacterial conjunctivitis or keratitis.
- Anti-inflammatory eye drops: These drops reduce inflammation in people who have uveitis or swelling after surgery.
- Glaucoma eye drops: These eye drops reduce intraocular pressure (IOP) to prevent damage to the optic nerve.
- Mydriatic eye drops: These drops dilate the pupils during comprehensive eye exams.
- Numbing eye drops: These drops contain local anesthetics to block the eye’s nerves from transmitting pain signals to the brain. They are often used before surgery or other eye tests.
Eye Drop Ingredients
Eye drops contain various ingredients to assist with lubrication and therapeutic effects. Some also contain preservatives to extend how long the drops can be used while others are preservative-free and therefore expire more quickly. Here are some examples of ingredients used:
Preservatives
- Benzalkonium chloride (BAK): A quaternary ammonium compound with effective antibacterial and antifungal properties used as a preservative.
- Polyquaternium-1 0.001%: Preservative similar to BAK that helps prevent microbial contamination and extends the shelf life of an eye drop.
Therapeutics
- Antibiotics: Used to treat bacterial infections of the eye. Some common ophthalmic antibiotics are ciprofloxacin, moxifloxacin, tobramycin, and erythromycin.
- Corticosteroids: Anti-inflammatory drugs used to treat a variety of ophthalmic conditions in which it is important to reduce/control inflammation.
- Antihistamine: Common antihistamines used in eye drops to reduce allergic symptoms include olopatadine hydrochloride, azelastine hydrochloride, and ketotifen.
- Prostaglandin Analogs: These drugs treat glaucoma by increasing the drainage of fluid from the eye and are often the first choice for controlling intraocular pressure.
- Natamycin: A topical antifungal medication to treat fungal infections in the outer layer of the eye.
Lubricants
- Polyethylene glycol 400: Acts to increase tear viscosity by forming a mucoprotective layer.
- Carboxymethylcellulose sodium: Stabilizes tear film and has mucoadhesive properties that allow it to remain on the ocular surface for prolonged periods of time.
- Glycerin: Attracts moisture to the eye and helps retain it there.
- Dextran: This ingredient increases the mechanical strength of the tear film.
Do Eye Drops Expire?
Keeping a bottle of eye drops in your bathroom cabinet for years may seem harmless, but the truth is these products do expire. Like food products, all eye drops have an expiration date clearly labeled. You should not use eye drops after the expiration date has passed.
According to the American Academy of Ophthalmology, unopened eye drops typically expire one to two years after their manufacturing date if stored and used correctly. However, once opened, many manufacturers recommend discarding eye drops after 28 days. Antibiotic eye drops usually only last a few days to a month after opening, and preservative-free eye drops do not last as long, either.
What to do if Eye Drops Expire
When eye drops expire, you should discard them, regardless of whether the bottle has been opened or not. Securely dispose of the expired eye drops by sealing the bottle and placing it in the trash. Make sure to not share expired drops with others.
In the event prescription eye drops have expired and you still have a medical need for drops, contact your eye doctor and inquire about a replacement or how to address your eye care needs.
What are the risks?
Using expired eye drops poses several potential risks to ocular health, including reduced effectiveness and the potential for contamination that increases the risk of eye infections.
Change in chemical composition: Eye drops can undergo changes in their chemical composition over time due to a range of factors such as exposure to air and light, as well as the breakdown of active ingredients. Temperature fluctuations can impact the stability of the solution, further contributing to alterations in chemical composition. These effects cause eye drops to be less effective. If you use eye drops for dry eye syndrome, allergies, or glaucoma, using expired eye drops can impact the overall management of your symptoms. The change in chemical composition can also cause irritation or pain.
Bacterial contamination: Over time, exposure to air and temperature changes can cause a breakdown of preservatives in eye drops. Without preservatives, bacteria can readily grow in eye drops and cause eye infections.
Fungal contamination: Preservatives also prevent the growth of fungi in eye drops. If expired drops contaminated with fungi are used, there is the potential to cause fungal keratitis, a serious infection that can cause redness, pain, and loss of vision.
