Fluorescein eye is a diagnostic test that uses a harmless orange dye (fluorescein) and a blue light to detect corneal abrasions (scratches), foreign bodies, or other damage to the cornea, the clear outer surface of the eye.
How the Fluorescein Eye Stain Test Works
The fluorescein eye stain test is a simple and quick procedure usually performed by an ophthalmologist or optometrist. Here's a breakdown:
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Application of Fluorescein: A small amount of fluorescein dye is applied to the surface of the eye, usually via a fluorescein-impregnated paper strip that is wetted with saline and gently touched to the inner surface of the lower eyelid.
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Examination with Blue Light: The doctor then uses a blue light to examine the eye. Under the blue light, fluorescein dye glows bright green in areas where the cornea is damaged.
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Interpretation: The bright green staining indicates areas where the corneal epithelium (the outermost layer of the cornea) is disrupted. This can reveal abrasions, ulcers, or other irregularities.
What the Test Detects
The fluorescein eye stain test is primarily used to identify the following:
- Corneal Abrasions: Scratches on the cornea.
- Corneal Ulcers: Open sores on the cornea, often caused by infection.
- Foreign Bodies: Presence of foreign objects on the cornea.
- Herpes Simplex Keratitis: A viral infection of the cornea.
- Dry Eye: In some cases, fluorescein can help assess the tear film and identify areas of dryness.
- Contact Lens-Related Problems: To check for corneal damage related to contact lens wear.
What to Expect During the Test
The fluorescein eye stain test is generally painless. Some people may experience mild and temporary stinging or discomfort upon application of the dye. The dye will temporarily stain the tears and may cause a temporary yellow or orange tinge to the skin around the eyes. This will dissipate quickly.
Potential Risks
The fluorescein eye stain test is very safe. Allergic reactions to fluorescein dye are rare. However, it is important to inform your doctor of any known allergies before the test. Contact lens wearers should remove their lenses before the test and typically wait a period of time before reinserting them. Your doctor will provide specific instructions.
