Fluorescein Staining for Corneal Abrasion: Procedure, Interpretation, and Clinical Value

Fluorescein sodium (orange dye) instilled in the eye fluoresces bright green under cobalt blue light (Wood's lamp or slit-lamp blue filter), revealing epithelial defects.

Procedure

1. Topical anesthetic (optional, but improves comfort).
2. Apply fluorescein strip (wet with saline) to inferior fornix or use 2% drops.
3. Patient blinks to distribute.
4. Examine under cobalt blue light with magnification.

Patterns & Interpretation

• Punctate stippling: Dry eye, superficial keratitis, contact lens overwear.
• Linear/geographic defect: Corneal abrasion (trauma, foreign body).
• Dendritic (branching): Herpes simplex keratitis — pathognomonic.
• Ring/central: Neurotrophic ulcer, exposure keratopathy.
• Vertical lines: Foreign body under upper lid (evert lid to find).

Clinical Pearls

• Photodocument for medico-legal and follow-up comparison.
• Seidel test (aqueous leak) — fluorescein streaming from wound under blue light.
• Rose bengal/lissamine green stain devitalized cells (dry eye, SJOGREN'S) — complementary.

Fluorescein staining is rapid, non-invasive, and the cornerstone of corneal integrity assessment.