Systane is an over-the-counter lubricating eye drop used to relieve dry eye symptoms, including burning, irritation, grittiness, and general discomfort. It works as an artificial tear, supplementing your natural tear film when your eyes aren’t producing enough moisture or when tears evaporate too quickly. You can buy it without a prescription, and the standard dosing is one or two drops in the affected eye as needed throughout the day.
Symptoms Systane Treats
Dry eye produces a surprisingly wide range of symptoms, and Systane is designed to address most of them. The classic ones are obvious: dryness, burning, and stinging. But dry eye also causes soreness, a gritty or sandy feeling, the sensation that something is stuck in your eye, sensitivity to light, and a general heaviness or fatigue in the eyes. These symptoms tend to worsen as the day goes on, which is why many people find themselves reaching for drops by afternoon or evening.
Systane is classified as a lubricant eye drop, not a medication. It doesn’t treat infections, allergies, or glaucoma. If your eyes are red and itchy from seasonal allergies, or if you have pain alongside vision changes, a lubricant drop isn’t the right tool.
How It Works on the Eye Surface
What sets Systane apart from basic saline drops is a polymer called hydroxypropyl-guar, or HP-Guar. This ingredient is derived from a natural plant-based compound and behaves differently inside the bottle than it does on your eye. In the bottle, it stays liquid. When the drop hits your tear film, the change in pH triggers a chemical reaction: borate molecules in the formula interact with calcium, zinc, and magnesium naturally present in your tears, causing the HP-Guar to cross-link into a soft, gel-like layer over the surface of your eye.
This gel layer does two important things. First, it mimics the mucin layer of your natural tear film, which is the innermost layer that helps tears stick to the eye’s surface. People with dry eye often have defects in this mucin layer, so the gel compensates for what’s missing. Second, it reduces friction between your eyelid and the surface of your eye during blinking, which is a major source of irritation when tears are inadequate.
HP-Guar molecules also preferentially bind to the driest, most damaged areas of the cornea rather than spreading evenly across healthy tissue. This means the protective layer concentrates where it’s needed most, shielding damaged cells and giving them time to repair.
The two active lubricant ingredients, polyethylene glycol 400 (0.4%) and propylene glycol (0.3%), provide the core moisturizing effect. The HP-Guar gel network holds these demulcents against the eye surface longer than a simple liquid drop would, which is why Systane tends to provide longer-lasting relief than basic artificial tears.
The Systane Product Line
Systane isn’t a single product. The brand includes several formulations tailored to different types of dry eye. The original Systane uses the HP-Guar gel system described above. Systane Complete is a newer formulation designed to address all three layers of the tear film. Systane Ultra targets aqueous-deficient dry eye, where the watery middle layer of the tear film is lacking.
The newest addition is Systane PRO PF, which launched in the U.S. in February 2025. It’s a preservative-free, multi-dose formula that combines three active components: hyaluronate (a moisture-binding molecule), nano-sized lipids (to reinforce the oily outer layer of the tear film), and HP-Guar. Alcon, the manufacturer, describes it as the longest-lasting drop in the Systane lineup.
The “PF” designation on any Systane product means preservative-free. This matters because preservatives in eye drops, while necessary to prevent bacterial contamination, can irritate sensitive eyes over time, especially with frequent use. If you’re using drops more than four times a day, preservative-free versions are generally the better choice.
Using Systane With Contact Lenses
Contact lens wearers deal with dry eye at higher rates than everyone else, and there’s good news here. A clinical study published in Investigative Ophthalmology & Visual Science found that Systane Complete can be safely applied directly onto soft contact lenses. Subjects in the study used the drops before putting lenses in, twice during wear, and after removal, with significant improvements in comfort and dryness. No adverse events were reported.
For the original Systane formula (which contains a preservative), the guidance is different. You should remove your contacts before applying drops and wait at least 15 minutes before reinserting them. Always check the label on the specific Systane product you’re using, since compatibility varies across the lineup.
Side Effects and Precautions
Systane is well tolerated by most people. The most common side effects are mild and temporary: brief blurry vision right after instilling the drop (the gel takes a moment to spread and clear) and occasional eye irritation. These typically resolve on their own within a minute or two.
Allergic reactions are rare but possible. Signs include skin rash, itching, hives, or swelling of the face, lips, tongue, or throat. If any of these occur, stop using the drops immediately.
There are a few situations where you should talk to a healthcare provider before using Systane or any artificial tear. These include active eye infections, recent eye injury, unexplained changes in vision, pregnancy, and breastfeeding. If your symptoms persist beyond 72 hours of regular use, or if you develop eye pain or worsening redness, the problem likely goes beyond simple dryness and needs a professional evaluation.
What Systane Won’t Do
Systane manages symptoms. It doesn’t cure the underlying cause of dry eye. If your dry eye stems from an autoimmune condition, medication side effects, or chronic inflammation of the eyelid glands, you may need additional treatment beyond lubricating drops. For mild to moderate dry eye triggered by screen use, dry indoor air, wind, or aging, Systane on its own is often enough to keep symptoms under control. Many people use it as a daily maintenance tool, applying drops a few times throughout the day whenever discomfort flares up.