Schirmer's Tear Test: Clinical Overview and Guidelines
Why Schirmer's Testing Matters
Schirmer's Tear Test quantifies aqueous tear production and helps differentiate aqueous deficient dry eye from primarily evaporative disease. By measuring strip wetting over five minutes, clinicians gain an objective data point that supports diagnosis, staging, and treatment planning. Adequate baseline tearing protects the corneal epithelium, maintains optical quality, and reduces infection risk, so identifying deficiency early prevents long term surface damage and patient frustration.
Procedure and Test Variations
A sterile filter paper strip is placed in the inferior temporal fornix and the patient gently closes the eyes for five minutes before wetting length is recorded. Schirmer I without anesthesia measures combined basal and reflex tearing, while repeating the test after topical anesthetic suppresses reflex input and isolates basal secretion. Consistency in strip placement, room conditions, and instruction to avoid squeezing eyelids improves reproducibility and comparability over time.
Normative Values and Clinical Interpretation
Typical reference points include 10 mm or more in five minutes as normal, 5 to 9 mm as borderline or mild deficiency, and 5 mm or less as severe aqueous deficiency. Values should be interpreted alongside symptoms, tear break up time, staining patterns, and osmolarity because false lows can occur with anxiety or poor cooperation and falsely high readings may follow reflex stimulation. Use the provided table as a quick chairside check but confirm trends with repeat testing when results and symptoms disagree.
Common Pitfalls and How to Avoid Them
Reflex tearing from touching the cornea, talking during the test, or bright lighting can inflate results, while antihistamines, antidepressants, and dehydration can depress them. Incomplete lid closure shortens wetting and excessive squeezing increases it. Standardize timing during the visit, control environmental airflow, and document whether anesthesia was used so future comparisons are meaningful. Repeat questionable tests rather than making management decisions on a single outlier value.
Treatment Decisions Based on Schirmer's Results
Low readings support escalation to preservative free lubricants, punctal occlusion, immunomodulators such as cyclosporine or lifitegrast, and oral secretagogues in severe cases. Borderline values may respond to environmental changes, hydration, omega 3 supplementation, and lid hygiene if evaporative components coexist. Combine Schirmer data with meibography and staining to decide whether to target aqueous replacement, lipid restoration, or inflammation control first. Recheck values after major therapeutic changes to document objective improvement.
Documentation, Follow Up, and Communication
Record which eye was tested first, anesthesia status, duration, and exact millimeter values for both eyes. Schedule follow up intervals that match disease severity and therapy intensity so results can be trended rather than viewed in isolation. Provide patients with a simple explanation of what the numbers mean and how treatments aim to raise comfort, not just the score. Clear records enhance continuity of care and support evidence based adjustments at subsequent visits.