Systane eye drops are safe for most people when used as directed. The active ingredients, polyethylene glycol 400 (0.4%) and propylene glycol (0.3%), are well-established lubricants approved for temporary relief of burning and irritation caused by dry eyes. That said, the safety picture gets more nuanced depending on which Systane formula you’re using, how often you use it, and whether you wear contact lenses.
What’s Actually in Systane
Systane’s two active ingredients work as lubricants that coat the surface of your eye, mimicking the moisture your natural tear film provides. They don’t treat underlying conditions. They temporarily reduce dryness, burning, and irritation. The formula is designed for short-term, as-needed use, though many people rely on it daily for chronic dry eye.
Beyond the active ingredients, the more important safety question for frequent users involves the preservative. Most multi-dose Systane bottles contain a preservative called Polyquad. Preservatives keep bacteria from growing inside the bottle after you open it, but they can also irritate the surface of your eye over time.
The Preservative Question
Polyquad is roughly 27 times larger than benzalkonium chloride (BAK), the older preservative found in many eye drops. Its size and chemical properties make it harder for the molecule to penetrate the cells on your eye’s surface, which in theory means less damage. Lab studies and some clinical trials support this: corneal and conjunctival cells exposed to Polyquad show less cell death and better survival rates compared to BAK.
However, Polyquad isn’t completely harmless. In vitro studies have shown it can still reduce cell viability and trigger inflammatory markers. Not every comparative study has found it clearly safer than BAK. For occasional use, the preservative in standard Systane bottles is unlikely to cause problems. But if you’re using drops four or more times a day, or you plan to use them for months, the cumulative exposure to any preservative becomes a real consideration.
Who Should Use Preservative-Free Systane
Systane offers preservative-free versions (labeled “PF”) that come in single-use vials instead of multi-dose bottles. These are the better choice if you fall into any of these categories:
- Frequent users: anyone instilling drops more than four times daily
- Contact lens wearers: preservatives can absorb into soft lenses and concentrate on the eye
- People with severe dry eye or other ocular surface conditions
- Anyone using multiple preserved eye drops for other conditions like glaucoma
- Known preservative allergy or sensitivity
- Long-term daily use: months or years of treatment
People who spend long hours in front of screens, work in dry or air-conditioned environments, or are older (especially women) also tend to benefit from the preservative-free option, since these factors increase both the frequency of use and the vulnerability of the eye’s surface.
Side Effects to Watch For
Systane’s side effect profile is mild. Some people experience temporary irritation or brief blurring right after putting in the drops. This typically clears within a minute or two.
Stop using the drops and follow up with an eye care provider if you notice eye pain, changes in your vision, or redness and irritation that persists beyond 72 hours. These symptoms are uncommon, but they can signal an allergic reaction or an underlying problem that lubricating drops won’t fix.
Contact Lens Safety
Not all Systane products are interchangeable when it comes to contacts. Systane makes a specific formulation called Systane Contacts that’s designed for use while lenses are in. Standard Systane bottles with preservatives should generally be used only after removing your lenses. If you wear contacts and prefer a non-contact-specific drop, preservative-free single-use vials are the safest route, since there’s no preservative to accumulate in the lens material.
Safety After Eye Surgery
Systane has been studied specifically in patients recovering from LASIK. In a randomized clinical trial, patients used one to two drops in each eye twice daily starting the day of surgery and continuing for 30 days. They were also allowed to use the drops as often as every 30 minutes on the day of surgery itself. The study concluded that Systane is safe for post-LASIK dry eye relief and recommended starting it immediately after the procedure to reduce discomfort during recovery.
The 2024 Recall
In December 2024, Alcon (the company that makes Systane) voluntarily recalled a single lot of Systane Ultra PF single-use vials after a consumer found foreign material inside a sealed vial that turned out to be fungal contamination. The recall was limited to lot number 10101 of the 25-count Systane Ultra PF on-the-go package, with an expiration date of September 2025. Fungal contamination in an eye product can cause infections that threaten vision, and in rare cases pose serious risk to immunocompromised individuals.
If you have this specific product, check the lot number on the carton. The packaging features a green and pink design with “Systane” and “ULTRA PF” on the front. No other Systane products were affected. This was a manufacturing issue with one batch, not a systemic safety problem with the formula.
How to Use Systane Safely
For occasional dry eye relief, standard Systane from a multi-dose bottle is a reasonable and safe choice. Use one to two drops per eye as needed. Don’t touch the dropper tip to your eye or any other surface, since this introduces bacteria into the bottle. Discard the bottle after the timeframe listed on the packaging, even if drops remain.
If you find yourself reaching for the drops multiple times a day, most days of the week, switching to preservative-free vials reduces your long-term exposure to chemicals that can gradually wear on the eye’s surface. Each single-use vial should be discarded after one use, since it has no preservative to prevent bacterial growth once opened.