Fluorescein Testing After Chemical Spray Eye Exposure
Yes, fluorescein strip testing is essential after chemical spray exposure to the eye and should be performed after thorough irrigation to assess for corneal epithelial damage and guide treatment decisions.
Immediate Management Priority
The first priority is copious irrigation to remove all chemical residue before any diagnostic testing 1. Once irrigation is complete, fluorescein testing becomes a critical diagnostic step.
Why Fluorescein Testing is Required
Detection of Epithelial Injury
- Fluorescein dye specifically stains areas where corneal epithelial intercellular junctions are disrupted, allowing visualization of chemical-induced damage that may not be visible on standard examination 2, 3.
- Chemical injuries can cause extensive ocular surface epithelial damage that requires documentation and monitoring 1.
- The staining pattern reveals the extent and location of epithelial defects, which directly impacts treatment decisions and follow-up timing 4, 5.
Clinical Grading and Prognosis
- After chemical injury, it is essential to clinically grade the severity of injury by assessing corneal stromal clarity and epithelial damage using fluorescein 1.
- The presence and size of epithelial defects identified by fluorescein determine whether prophylactic antibiotics are needed and how aggressively to treat 4.
Proper Testing Technique
Application Method
- Use saline-moistened fluorescein strips applied to the inferior tarsal conjunctiva 2, 3.
- Avoid fluorescein-anesthetic combination drops as anesthetics may affect test results 3.
- Perform fluorescein staining before instillation of any other eyedrops to avoid false results 3, 5.
Examination Protocol
- Examine the ocular surface through a biomicroscope using a cobalt blue filter 2.
- Wait approximately 2 minutes after application for optimal visualization 2, 3.
- Use a yellow filter in conjunction with cobalt blue light for enhanced visualization of corneal staining 2, 3.
Treatment Implications Based on Findings
If Epithelial Defect is Present
- Initiate broad-spectrum topical antibiotic prophylaxis immediately (ideally within 24 hours) to prevent progression to bacterial keratitis 4.
- Fluoroquinolone drops (moxifloxacin or gatifloxacin) 4 times daily are first-line therapy 4.
- Never patch the eye - this delays healing and increases infection risk 4.
- Avoid topical steroids initially as they delay epithelial healing 4.
Follow-Up Timing
- Re-evaluate in 24 hours for any epithelial defect, except small abrasions (≤4 mm) with normal vision 4.
- Chemical injuries require close monitoring as they can progress despite initial treatment 1.
Critical Pitfalls to Avoid
- Failure to perform fluorescein testing means you cannot accurately assess the extent of injury or make appropriate treatment decisions 4, 5.
- Testing before adequate irrigation is complete will not provide accurate assessment 1.
- Delaying antibiotic prophylaxis when epithelial defects are identified increases risk of serious infection 4.
Warning Signs Requiring Urgent Ophthalmology Referral
Immediate referral is indicated for 4:
- Increasing pain despite treatment
- Purulent discharge development
- Corneal infiltrate or ulcer on examination
- Significant vision loss
- Symptoms worsening or not improving within 24-48 hours