Can fluorescein dye visualize an abrasion on the sclera?

Fluorescein Dye Visualization of Scleral Abrasions

Fluorescein dye can effectively visualize abrasions on the sclera, as it stains areas of epithelial disruption across the ocular surface, including the sclera, though it is more commonly used for corneal evaluation. 1, 2

Mechanism of Fluorescein Staining

Fluorescein dye works by:

• Staining areas of the ocular surface where there is disruption of intercellular junctions, allowing the dye to permeate into the tissue 3
• Staining individual cells rather than merely pooling in areas of cell dropout 4
• Appearing more intense when observed with a yellow filter in conjunction with the cobalt blue filter 3, 1

Proper Technique for Scleral Evaluation

For optimal visualization of scleral abrasions:

1. Preparation and Application:

   • Moisten a fluorescein strip with sterile nonpreserved saline 3, 1, 5
   • Apply the moistened strip to the inferior tarsal conjunctiva 3, 1
   • Allow the patient to blink several times to distribute the dye 5

2. Examination:

   • Use a slit-lamp biomicroscope with a cobalt blue filter 3
   • Wait approximately 2 minutes for optimal visualization 1
   • Use a yellow filter in combination with the cobalt blue filter for enhanced visualization 1
   • Examine the entire ocular surface, including the sclera 6

Clinical Considerations

• While fluorescein staining is more commonly discussed for corneal evaluation, anterior segment fluorescein angiography has been used specifically to evaluate scleral inflammation and can distinguish various forms of scleritis and episcleritis 2
• Fluorescein staining can detect areas of epithelial disruption across the ocular surface, including scleral abrasions 7, 6
• Mild fluorescein staining can be observed in normal eyes and may be more prominent in the morning 3, 1

Advantages Over Alternative Stains

• Fluorescein is preferred over Richardson's stain for epithelial defects as it:
  • Does not decrease re-epithelialization rate
  • Does not delay wound closure
  • Does not slow the return of edematous tissue to normal thickness 8

Precautions

• Avoid using fluorescein-anesthetic combination drops as the anesthetic may affect test results 3
• Evaluate before instillation of any other eye drops and before eyelid manipulation 3
• While rare, be aware that systemic reactions can occur with topical fluorescein application 1

By following these guidelines, clinicians can effectively use fluorescein dye to visualize and assess scleral abrasions, aiding in accurate diagnosis and appropriate management of ocular surface injuries.