Ocular surface staining is a test that can help with diagnosing certain eye conditions. It involves using different dyes to show damaged tissues. The dye does not cause any permanent discoloration.

Ocular surface staining can guide treatment decisions and help rule out certain conditions. For example, fluorescein staining uses a yellow dye that attaches to the epithelium of the eye. This makes it easier to see damage to the tissue from cuts, scrapes, and foreign objects.

A doctor may recommend ocular surface staining as part of an eye exam or when a person has symptoms of an underlying disease, such as dry eye or Sjogren’s disease.

Read on to learn more about ocular surface staining, including what happens in the procedure, the dyes doctors use, and what the results mean.

Close-up of a brown eye looking upward.Share on Pinterest
Ben Welsh/Getty Images

Ocular surface staining is an eye test that involves using dyes to temporarily change the color of the outer tissue of the eye. This makes it easier to diagnose certain types of eye problems, such as foreign objects in the eye.

Ophthalmologists use different types of eye dyes in different situations. Many dyes, such as brilliant blue and acid blue, are for use during surgery to better see internal eye structures. This is not ocular surface staining.

Instead, ocular surface staining involves applying dye to the outer portion of the eye during nonsurgical procedures, such as when testing for dry eye or small eye injuries.

Depending on the case, doctors may use a single dye or multiple dyes to get the best coverage.

Some types of dyes a doctor might use in ocular surface staining include:


Fluorescein is one of the most common dyes for ocular surface staining because it has many applications. It attaches to the eye’s basement membrane, making it easy to detect areas where the tissue has broken down.

Some uses for this yellow dye include:

  • seeing foreign objects in the eye
  • detecting eye injuries, such as corneal abrasions
  • detecting abnormalities in the blood vessels of the eyes
  • measuring the stability of the eye’s tear film to help detect chronic dry eye

Fluorescein sometimes causes stinging in the eye.

Rose bengal

Rose bengal is a dye that comes from fluorescein. It can detect many of the same conditions as fluorescein, but it may be able to detect changes in the cornea earlier in some diseases. This is because this dye may be able to stain areas of the eye surface that have no tear film rather than only dead or damaged cells.

Rose bengal dye may reveal:

Rose bengal often stings and causes irritation, and it can be toxic to the surface of the eye, so doctors tend to use other options where possible.

Lissamine green

Lissamine green is an organic substance that scientists produce in a lab. It is not toxic — some companies use it as a food additive.

This dye attaches more readily to dead and damaged cells. This makes it useful in detecting eye diseases and some injuries. A doctor may recommend lissamine green for the following purposes:

  • diagnosing chronic dry eye
  • ruling out keratoconjunctivitis sicca in people with Sjogren’s disease
  • determining the right fit for contact lenses

People usually tolerate lissamine green better than rose bengal.

Doctors commonly use ocular surface staining to diagnose dry eye. It may help determine the cause of dry eye, too. For example, the test may show that the eye is not producing sufficient tears.

Sometimes, staining can help diagnose meibomian gland dysfunction. This condition occurs when the tiny glands in the eyelid that help lubricate the eye do not produce enough lubrication.

Some other conditions a doctor may diagnose with ocular surface staining include:

  • foreign objects in the eye
  • corneal abrasions, which are injuries to the cornea
  • diseases of the blood vessels of the eyes
  • cancer of the eye

There are several ways of performing ocular surface staining. One method involves applying a small strip of paper that comes pre-loaded with dye to the eye.

First, a doctor will open the packet, dip the paper in saline, and then hold the eye open and apply the paper to the eye. A person may need to blink several times to distribute the dye.

If a person may have a foreign object in the eye, the doctor may use eye drops instead, applying 1–2 drops in the affected eye.

In cases where a doctor wants to evaluate the retina, they may have the person take fluorescein by mouth. When this happens, it takes 10–15 minutes to appear in the eye. Another option involves injecting the dye into a vein in the arm, which causes the dye to appear in the retina in seconds.

When using fluorescein, a doctor will examine the eye under a blue light. For other dyes, doctors may use other lights or examine the eye using several different lights.

Depending on the test the doctor is doing, they may ask the patient to look straight ahead, or they perform other tests or examinations during the procedure.

Ocular surface staining may cause stinging. Sometimes, this stinging is intense. People may also experience other side effects. Some common ones are:

  • changes in taste
  • burning or prickling in the lips
  • dizziness
  • nausea
  • vomiting
  • abdominal pain
  • chest pain

If the doctor delivered the dye via injection, there may also be some inflammation or irritation around the injection site. A person’s urine may also change color temporarily.

People can be allergic to eye dyes. If they are, they may experience rashes, itchiness, or hives. In severe cases, people may experience a serious allergic reaction known as anaphylaxis, although this is more likely with oral or injection administration.

A medical professional will monitor a person for a reaction after the test to make sure this does not occur.

Depending on what the doctor is looking for via ocular surface staining, they may assign a score to the test. This indicates how intensely the eye has shown the stain. Higher scores indicate a higher stain intensity and point to a higher risk of eye disease, especially dry eye.

Scoring systems vary from dye to dye and practitioner to practitioner, so a person should ask about the specific scoring system their doctor is using.

If a doctor is performing the test to identify a specific object or injury, they may not assign a score.

Ocular surface staining tests can sometimes produce immediate results, so a doctor may begin discussing the next steps for treatment during the same appointment. They will talk through the available options and their advantages and disadvantages.

They may recommend a particular course of treatment right away or follow up at a later date after reviewing a person’s results and medical history.

When ocular staining tests do not provide a clear diagnosis, a doctor may recommend additional tests, including other ocular stains, to identify the cause of a person’s symptoms.

Before an ocular surface staining test, a person may want to ask their doctor questions, such as:

  • What is the test for, and what is it likely to find?
  • What are the potential side effects?
  • How long will it take to get my results?
  • What is the next step after this test?
  • What should I do if the dye stings?
  • What are the alternatives to this test?

Ocular surface staining is a diagnostic test that looks for signs of damage or dryness in the eye. It involves a doctor applying dye to the eye to show areas of damage on its surface. This may help diagnose injuries, dry eye, or other conditions.

This test is a safe procedure, but it may cause stinging in the eye or other side effects in some people. People who have questions or concerns about the test or their results should speak with a doctor.