What is a Seidel Exam?
The Seidel test is a diagnostic procedure using fluorescein dye and cobalt blue light to detect aqueous humor leakage from corneal or conjunctival wounds following trauma, surgery, or suspected perforation. 1
Purpose and Clinical Indications
The test is essential for identifying:
- Leaks from corneal or conjunctival wounds after trauma or surgery 1
- Spontaneous aqueous leakage in conditions like corneal ulceration 1
- Self-sealed perforations that may not be clinically obvious 2
Test Procedure
Materials Required
- Fluorescein dye strip and cobalt blue light (typically from a slit lamp) 1
Preparation Steps
- Moisten the fluorescein strip with sterile saline solution for at least one minute to achieve adequate dye concentration 1
- Perform the test BEFORE instilling any other drops that might wash away or dilute the fluorescein 1
Application Technique
- Apply the fluorescein directly to the suspected leak site or surgical wound, ensuring the dye covers the entire area of concern 1
- Observe under cobalt blue light immediately after application 1
Interpretation of Results
Positive Test
- A positive Seidel test shows aqueous humor flowing from the wound, diluting and washing away the fluorescein, creating a characteristic clear streaming pattern 1
- Subtly positive tests may show minimal leak with subtle dilution pattern, requiring careful observation 1
Negative Test
- Fluorescein remains concentrated at the wound site without streaming or dilution 1
- However, a negative test does not guarantee wound integrity, as demonstrated in cases where self-sealed perforations later opened 2
Documentation Requirements
When performing the test, you must record:
- Location, size, and rate of any observed leakage 1
- Whether the leak is continuous or intermittent 1
- Associated findings such as shallow anterior chamber or hypotony 1
Critical Clinical Caveats
Safety Considerations
- Avoid puff tonometry in patients with suspected corneal perforation, even with a negative Seidel test, as the air-jet can temporarily distort wound integrity and reopen self-sealed perforations 2
- The test itself is non-invasive and safe when performed correctly 1