Boric Acid Eye Wash

Benefits, Side Effects, and How to Use It

A boric acid eye wash can be effective for flushing eyes exposed to grit or other foreign objects. You can also use it to ease dry, irritated, or burning eyes. Boric acid eye washes have been used for generations to cleanse irritated eyes and fight infection.

This article will go over the uses of boric acid eye wash. You'll also learn about the risks and possible side effects.

Verywell / Brianna Gilmartin

What Is Boric Acid Eye Wash?

Boric acid, also known as hydrogen borate (H3BO3), is a weak acid derived from the mineral boron. It is widely used in over-the-counter (OTC) antiseptics and astringents. In its natural form, boric acid is a colorless or white crystal that can be finely ground into a powder and dissolved in water.

While toxic if you eat or drink it, boric acid has beneficial properties when used as an eyewash. Most boric acid eye washes are an isotonic saline solution (one that has the same amount of salt as your blood) made with purified water, sodium chloride (salt), and other ingredients.

The level of boric acid in an OTC eye wash is extremely low—generally around 0.02%. That means it poses no harm to the eyes or surrounding tissues.

According to the European Medicines Agency, each 50 microliter (mL) drop contains only around 0.004 milligrams (mg) of boron, well below the allowable limit of 1.0 mg per day.

Boric Acid Eye Wash Uses

There are many types of boric acid eyewashes you can get at the store. Most are used to cleanse and refresh the eyes when they are mildly irritated. Other boric acid eye washes, such as antihistamine eye drops like Visine-A or Opcon-A, support the treatment of an eye infection or other conditions.

Boric acid eye washes can be used to rinse foreign substances from the eye, including chlorinated water, dust, smoke, chemicals, and smog.

A boric acid eye wash can also be used to relieve eye irritation caused by:

Do Boric Acid Eye Washes Treat Infections?

Boric acid eye washes do not treat the underlying condition—they just ease your symptoms. This is especially true if you have fungal eye infections or severe allergy symptoms—both of which require different treatments.

While boric acid has antibacterial and antifungal properties, the actual effect is minimal at such low concentrations. If you think you have an eye infection, call your provider.

Boric Acid Eye Wash Benefits

Boric acid eye wash may have several benefits, including:

  • Mild antiseptic properties: Boric acid eye wash may help stop or prevent (inhibit) bacterial and fungal growth and help prevent some mild infections.
  • Compatible with your eye tonicity: Boric acid eye wash drops do not diffuse or dilute the essential chemicals in your eye fluid. That's why it's good for irrigation, as it doesn't disrupt your eye’s natural chemistry.
  • Acts as a buffering agent: Buffering agents maintain the pH balance of a solution even if alkaline or acid is added. This means other active or inactive ingredients can be added to the boric acid eye wash without altering the pH balance of the solution.

How to Use a Boric Acid Eye Wash: Step-by-Step

Depending on your need and the brand of solution used, a boric acid eye wash can be applied with an eye dropper or eyecup. Here's how to use boric acid eye wash.

Always read the product label and follow the instructions for the eye wash you choose. Talk to your healthcare provider or pharmacist to make sure you know how to use them correctly.

Before Using a Boric Acid Eye Wash

Before you use a boric acid eye wash, there are a few things to keep in mind:

  • If you wear contact lenses, remove them before using a boric acid eye wash. The preservatives used in some boric acid eye wash solutions can be absorbed by the lenses and cause discoloration. Wait for at least 15 minutes following an eye wash before replacing your contacts.
  • You should avoid using the eye wash if you have sores or open wounds in or around the eyes.
  • Never use an eye wash that is either cloudy or past its expiration date.

Using an Eyedropper

Some boric acid eye washes come with an eyedropper. Here are the steps for using these products:

  1. Open the eye dropper bottle.
  2. Tilt your head back and tug the lower eyelid gently downward.
  3. Position the dropper over your eyeball without touching it.
  4. Apply only the number of drops recommended.
  5. Close your eyelid to draw the liquid over the eyeball surface.
  6. Blot any excess fluid from around your eye.
  7. Repeat with the other eye, if needed.
  8. Rinse the cap with water and replace it tightly.

Using an Eye Cup

Boric eye washes can also come with an eye cup instead of a dropper. Here are the steps for using them:

  1. Open the bottle.
  2. Pour as much eyewash into the cup as is recommended.
  3. Tilt your head forward over the kitchen sink.
  4. Place the cup firmly around the eye.
  5. Tilt your head back and open the eye.
  6. Move your eyeball around so that it is fully immersed in the fluid.
  7. Tilt your head forward.
  8. Pour the contents of the cup down the drain.
  9. Repeat with the other eye, if needed.
  10. Rinse the cap with water and replace it tightly.

It's best to use a disposable eyecup, but you can reuse a cup if you wash it thoroughly with hot water and soap. Just avoid touching the rim or inside of the cup with your fingers.

Boric Acid Eye Wash Side Effects

Boric acid eye drops are considered safe if used as directed. Some people may feel a slight tingling sensation or brief blurriness after using the eye wash. Any side effects of boric acid eye washes are usually mild and go away within a few seconds or minutes.

Stop using a boric acid eye wash and call your provider if the side effects don't get better or you have serious side effects like:

  • Eye redness
  • Eye pain
  • Severe stinging or burning
  • Eyelid inflammation
  • Itchy eyes
  • Persistent weepy eyes
  • Vision changes
  • Worsening of your eye condition

Allergic reactions to a boric acid eye wash are rare, but they can happen. Some people develop symptoms of contact dermatitis (redness, rash, inflammation) when they use boric acid eye washes.

Boric Acid Eye Wash Interactions

Never use a boric acid eye wash with contact lens wetting solution or any other ophthalmologic solution that has polyvinyl alcohol (PVA). This interaction can increase the pH balance of the eye wash and make it more acidic, which can irritate your eyes.

A Word From Verywell

Boric acid eye washes have been a mainstay of eye care for generations. While they do not treat eye infections, they can help relieve symptoms.

If you want to use boric acid eye wash, buy an over-the-counter (OTC) product rather than making your own eye wash at home. If you were to use the wrong amount of boric acid in the water or you contaminate it, you could seriously hurt your eyes.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. José AC, Castelo branco B, Ohkawara LE, Yu MC, Lima AL. [Use conditions of boric acid solution in the eye: handling and occurrence of contamination]. Arq Bras Oftalmol. 2007;70(2):201-7. doi:10.1590/s0004-27492007000200004

  2. Overview of comments received on the draft 'Questions and answers on boric acid’ (EMA/CHMP/619104/2013).

Additional Reading

By James Myhre & Dennis Sifris, MD
Dennis Sifris, MD, is an HIV specialist and Medical Director of LifeSense Disease Management. James Myhre is an American journalist and HIV educator.