Schirmer Test Interpretation
Interpret Schirmer test results based on which version was performed (with or without anesthesia), using specific cutoff values: Schirmer I (without anesthesia) <5.5 mm at 5 minutes is diagnostic of aqueous tear deficiency, while Schirmer with anesthesia <3 mm at 5 minutes is highly diagnostic, with 3-10 mm being equivocal.
Test Methodology Matters
The interpretation fundamentally depends on whether topical anesthesia was used, as this dramatically affects results 1:
Schirmer I (Without Anesthesia)
- <5.5 mm at 5 minutes: Diagnostic of aqueous tear deficiency
- <10 mm at 5 minutes: Suggestive of abnormality (though no absolute cutoff established)
- 5-10 mm: Relatively insignificant (basal secretion score)
Schirmer with Anesthesia (Schirmer II/Basic Secretion Test)
- <3 mm at 5 minutes: Highly diagnostic of aqueous tear deficient dry eye
- 3-10 mm: Equivocal zone - requires correlation with other findings
- >10 mm: Generally normal
Schirmer II (Reflex Secretion Test)
- <15 mm at 2 minutes: Abnormal (after nasal mucosa stimulation)
Critical Interpretation Principles
Single abnormal results are nonspecific - the guideline explicitly states that serially consistent low results are strongly suggestive of aqueous tear deficiency 1. This is a crucial caveat: don't diagnose based on one test alone.
The Schirmer test has inherent variability and should not be used as the sole criterion for diagnosing dry eye 1. The test has only 51% specificity for dry eye diagnosis 1, making it less reliable than tear osmolarity testing.
Practical Testing Considerations
When performing the test with anesthesia, remove excess fluid from the cul-de-sac before inserting the filter paper 1. The test measures wetting over 5 minutes for standard Schirmer testing, with the strip placed in the temporal one-third of the inferior cul-de-sac 1.
Research shows that Schirmer with anesthesia is more objective and reliable than without anesthesia, particularly for aqueous-deficiency dry eye (ADDE) 2. The anesthetized version eliminates reflex tearing, providing a more accurate assessment of basal tear production.
Time-Saving Alternative
If 5 minutes is impractical, a 1-minute test correlates highly with the 5-minute test 3. Specifically, 100% of patients with severe dry eye (5-minute test ≤5.5 mm) had 1-minute results ≤2 mm, and 80% with moderate dry eye (5-minute test 5.5-10 mm) had 1-minute results of 3-6 mm.
Context-Dependent Interpretation
Age, sex, and medications affect results 4. Male sex, higher age, and various topical (prostaglandin, beta-blocker drops) and systemic medications (NSAIDs, thyroid hormones, sedatives) are associated with lower Schirmer values. Consider these factors when interpreting borderline results.
For Sjögren's syndrome diagnosis, the European-American consensus criteria use Schirmer <5 mm in 5 minutes (without anesthesia) as one diagnostic criterion worth 1 point 1.
Clinical Integration
Always correlate Schirmer results with:
- Patient symptoms (burning, stinging, photophobia)
- Tear film break-up time
- Corneal/conjunctival staining patterns
- Tear osmolarity when available
The fluorescein dye disappearance test shows better correlation with symptoms and corneal staining than Schirmer testing 1, so consider using complementary tests when Schirmer results are equivocal.