Fluorescein eye stain

This is a test that uses orange dye (fluorescein) and a blue light to detect foreign bodies in the eye. This test can also detect damage to the cornea. The cornea is the outer surface of the eye.

A piece of blotting paper containing the dye is touched to the surface of your eye. Sometimes the dye comes in a drop form which also contains anesthetic. You are asked to blink. Blinking spreads the dye and coats the tear film covering the surface of the cornea. The tear film contains water, oil, and mucus to protect and lubricate the eye.

The health care provider then shines a blue light at your eye. Any problems on the surface of the cornea will be stained by the dye and appear green under the blue light.

The provider can determine the location and likely cause of the cornea problem depending on the size, location, and shape of the staining.

How to Prepare for the Test

You will need to remove your eyeglasses or contact lenses before the test.

How the Test will Feel

If your eyes are very dry, the blotting paper may be slightly scratchy. The dye may cause a mild and brief stinging sensation if there is no anesthetic used.

Why the Test is Performed

This test is to:

Find scratches or other problems with the surface of the cornea
Reveal foreign bodies on the eye surface
Determine if there is irritation of the cornea after contacts are prescribed

Normal Results

If the test result is normal, the dye remains in the tear film on the surface of the eye but does not show any abnormal areas.

What Abnormal Results Mean

Abnormal results may point to:

Abnormal tear production (dry eye)
Blocked tear duct
Blocked tear duct
A blocked tear duct is a partial or complete blockage in the pathway that carries tears from the surface of the eye into the nose.
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Corneal abrasion (a scratch on the surface of the cornea)
Corneal abrasion
Corneal injury is a wound to the part of the eye known as the cornea. The cornea is the crystal clear (transparent) tissue that covers the front of ...
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Foreign bodies, such as eyelashes or dust (foreign object in eye)
Foreign object in eye
The eye will often flush out small objects, like eyelashes and sand, through blinking and tearing. DO NOT rub the eye if there is something in it. ...
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Infection
Injury or trauma
Severe dry eye associated with arthritis (keratoconjunctivitis sicca)

Often the test is done to check for any of the conditions listed above.

Risks

If the dye touches the skin, there may be a slight, brief, discoloration. It may stain your clothing or other fabric.

Open References

References

Fowler GC. Corneal abrasions and removal of corneal or conjunctival foreign bodies. In: Fowler GC, ed. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 200.

Knoop KJ, Dennis WR. Ophthalmologic procedures. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 62.

Fluorescent eye test - illustration
The fluorescent eye test is useful in determining if there is a scratch or other problem with the surface of the cornea. It can also be used to detect foreign bodies on the surface of the eye, and determine if there is an injury to the eye or eye infection. The test is performed by administering dye onto the eye's surface. After the dye has thoroughly covered the eye a cobalt blue light is then directed on the eye. The light causes the dye to glow green. Abnormalities in the corneal epithelium will cause the dye to stain that region.
Fluorescent eye test
illustration

Fluorescent eye test - illustration
The fluorescent eye test is useful in determining if there is a scratch or other problem with the surface of the cornea. It can also be used to detect foreign bodies on the surface of the eye, and determine if there is an injury to the eye or eye infection. The test is performed by administering dye onto the eye's surface. After the dye has thoroughly covered the eye a cobalt blue light is then directed on the eye. The light causes the dye to glow green. Abnormalities in the corneal epithelium will cause the dye to stain that region.
Fluorescent eye test
illustration

A Closer Look

Talking to your MD

Self Care

Tests for Fluorescein eye stain

Fluorescein eye stain

Review Date: 2/12/2023

Reviewed By: Franklin W. Lusby, MD, Ophthalmologist, Lusby Vision Institute, La Jolla, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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