For routine eye rinsing, store-bought sterile eye wash is the safest option. Homemade saline solutions carry a real risk of eye infection because achieving true sterility at home is extremely difficult. That said, understanding how saline works, when tap water is acceptable in an emergency, and how to rinse your eyes properly can make a meaningful difference when you need it.
Why Homemade Eye Wash Is Risky
A normal saline solution is just water and salt at a 0.9% concentration: 9 grams of salt per liter of water. That ratio closely matches your body’s own fluids and the natural pH of your eye’s surface, which sits around 7.11. In theory, it’s simple to mix. In practice, the problem isn’t the recipe. It’s contamination.
The Cleveland Clinic explicitly advises against using homemade saline in your eyes, citing the risk of serious infection. One organism of particular concern is Acanthamoeba, a microscopic parasite that thrives in water, including treated tap water, bottled water, and even chlorinated pool water. It causes a corneal infection called Acanthamoeba keratitis, which accounts for at least 90% of its cases among contact lens wearers. Left untreated, it can lead to permanent vision loss, glaucoma, and cataracts.
Research from WebMD found that bacteria begin forming in homemade saline solutions within 24 hours. A study published in PubMed showed that homemade saline stored at room temperature tested positive for bacterial growth after two weeks. Even refrigerated solutions only stayed bacteria-free for about four weeks. A pharmacy-bought sterile eye wash, sealed and manufactured under controlled conditions, eliminates these risks entirely.
What to Buy Instead
Sterile saline eye wash is inexpensive and available at virtually any pharmacy or grocery store. Look for products specifically labeled as “eye wash” or “eye irrigating solution.” These come in squeeze bottles with nozzle applicators or in smaller dropper bottles. Some kits include a reusable eye cup. The solution inside is manufactured to be sterile, pH-balanced, and free of preservatives that could irritate your eyes.
If you wear contact lenses, keeping a bottle of sterile eye wash at home is especially worthwhile. Contact lens solution also works for rinsing eyes in a pinch, and it’s far safer than tap water. Never use tap water to clean, store, or rinse contact lenses.
How to Rinse Your Eyes Properly
Remove contact lenses before rinsing. Then choose one of two methods depending on what you have available.
With a squeeze bottle or nozzle applicator: lean your head back, open your eyes wide, and squeeze the solution directly into your eye. Keep the tip of the bottle away from your eye’s surface to avoid contamination. Blink several times and repeat as needed.
With an eye cup: rinse the cup with a small amount of the solution first, then fill it halfway. Press the rim firmly against the skin around your eye socket to create a seal. Tilt your head back, open your eye, and let the solution wash over it. The tight seal prevents leaking, but it takes a little practice. Rinse the cup thoroughly between uses on each eye.
Emergency Eye Flushing
If a chemical splashes into your eye, don’t wait to find sterile saline. The Mayo Clinic recommends flushing immediately with clean, lukewarm tap water for at least 20 minutes. Speed matters more than sterility in this situation. Getting the chemical out quickly is the priority.
The type of substance changes how long you should flush. For a foreign body like dust or debris, about a minute of rinsing is usually enough to clear it. For acid or alkali burns, which are far more damaging, emergency irrigation should continue for at least 15 minutes, and 30 minutes is better. Severe chemical burns may require continued gentle irrigation for 12 to 24 hours in a medical setting. After any chemical exposure, get to an emergency room even if your eye feels better after rinsing.
If You Still Want to Make Saline at Home
For non-eye uses like nasal irrigation or wound cleaning, a basic saline recipe is straightforward. Use distilled water (not tap) and non-iodized salt, sometimes labeled as pickling or canning salt. Regular table salt often contains iodine and anti-caking agents that can irritate mucous membranes. The University of Mississippi Medical Center recommends 2 level teaspoons of non-iodized salt per quart of distilled water. Adding 1 level teaspoon of baking soda can make the solution feel less irritating.
Store it in a clean container. To sterilize a glass jar, submerge it upright in a pot of water and boil for 10 minutes (add an extra minute for every 1,000 feet of elevation above sea level). Refrigerate the finished solution and use it within a few days. Even under refrigeration, homemade saline has a limited shelf life. Discard anything older than two weeks to be safe.
This solution is acceptable for rinsing sinuses or cleaning superficial wounds. It is not recommended for your eyes. The surface of your eye is uniquely vulnerable to infection, and the consequences of contamination are severe enough that the small cost of a store-bought sterile eye wash is worth it every time.