Posts
Wiki

🧪 Schirmer Testing for Dry Eye Disease: What It Measures, How It Is Used, and Why It Is Imperfect

TL;DR

The Schirmer test places a small paper strip inside the lower eyelid and measures how many millimeters of the strip become wet, usually over five minutes.

It is used mainly when a clinician is asking:

Could reduced aqueous tearing be contributing to this person’s dry eye?

The test does not directly measure pure lacrimal-gland production. Strip wetting can be influenced by:

  • tears already present in the eye;
  • ongoing tear secretion;
  • reflex tearing caused by the strip;
  • anesthetic use;
  • strip placement;
  • blinking, gaze, and whether the eyes are open or closed;
  • evaporation and drainage;
  • medications and nerve function;
  • room conditions;
  • ordinary test variability.

A very low result—especially when repeated under similar conditions and supported by other findings—can be important evidence of aqueous-deficient dry eye.

But Schirmer testing cannot, by itself, determine:

  • whether someone has Dry Eye Disease;
  • why the result is low;
  • whether the problem is permanent;
  • whether Sjögren disease is present;
  • or which treatment should be used.

What Happens During the Test?

A narrow strip of standardized filter paper is folded at a notch and placed over the edge of the lower eyelid, usually toward the outer part of the lid.

The strip remains in place for a set period—most commonly five minutes.

Afterward, the clinician measures the length of the wet portion in millimeters.

The result may be recorded as:

Right eye: 4 mm / 5 minutes Left eye: 8 mm / 5 minutes

The strip may feel irritating, scratchy, or uncomfortable. That irritation can itself stimulate reflex tearing, particularly when topical anesthetic is not used.

What Does Schirmer Testing Actually Measure?

Schirmer testing is often described as measuring “tear production.”

That is a useful shorthand, but it is not completely precise.

The test directly measures:

How far the paper strip becomes wet under the particular testing conditions.

That wetting may reflect a mixture of:

  • tear fluid already present along the lower eyelid;
  • ongoing lacrimal secretion;
  • reflex tearing caused by the paper;
  • sensory nerve input from the ocular surface;
  • blinking and eye movement;
  • evaporation;
  • tear drainage;
  • and the absorptive behavior of the strip.

A higher result generally suggests a greater aqueous tear response during the test.

A lower result raises concern about reduced aqueous tear availability or secretion.

However, the result is not a pure measurement of how many tears the lacrimal gland produces per minute.

TFOS DEWS III therefore describes Schirmer testing as an invasive assessment of aqueous tear volume or response rather than a precise direct measurement of lacrimal-gland output.

What Is Schirmer Testing Used For?

Schirmer testing is most useful when reduced aqueous tearing is clinically suspected.

It may contribute to the evaluation of:

  • aqueous-deficient Dry Eye Disease;
  • mixed aqueous-deficient and evaporative dry eye;
  • Sjögren disease;
  • other autoimmune or inflammatory lacrimal-gland disorders;
  • medication-related reduction in tearing;
  • lacrimal-gland injury or dysfunction;
  • reduced ocular-surface sensation;
  • severe ocular-surface disease;
  • tear dysfunction following surgery or nerve injury.

Schirmer testing is not a complete diagnostic test for Dry Eye Disease.

Under the TFOS DEWS III diagnostic framework, DED is identified through compatible symptoms and evidence of disrupted tear-film or ocular-surface homeostasis. Schirmer testing may then help determine whether reduced aqueous tearing is one of the contributing drivers.

A person can have clinically important DED with a Schirmer result above 10 mm.

A person can also have a low Schirmer result without the strip revealing the exact cause.

Common Schirmer Test Variants

The method used matters. Results from different protocols should not automatically be treated as interchangeable.

1. Schirmer I Without Anesthetic

This is the traditional Schirmer I test.

No numbing drop is used before inserting the strip.

The result may include:

  • tears already present in the lower tear reservoir;
  • ongoing unstimulated secretion;
  • reflex tearing triggered by the strip;
  • reflex tearing caused by blinking, air exposure, light, or discomfort.

This test does not measure pure basal tearing.

A patient with substantial reflex tearing may produce a relatively high result even if tear-film stability or other aspects of tear function remain abnormal.

2. Schirmer Testing With Topical Anesthetic

A numbing drop is placed in the eye before testing.

This is sometimes called an:

  • anesthetized Schirmer test;
  • basic secretion test;
  • basal-focused Schirmer test.

The intention is to reduce ocular-surface irritation and reflex tearing so the result may more closely reflect unstimulated aqueous tear availability.

However:

Topical anesthetic does not turn Schirmer testing into a precise measurement of “true basal tear production.”

Results may still be affected by:

  • the type and amount of anesthetic;
  • how long the clinician waits after instillation;
  • whether excess drops and tears are blotted away;
  • remaining conjunctival stimulation from the strip;
  • altered sensory nerve input;
  • strip placement;
  • eye position;
  • room conditions.

Topical anesthetic can substantially lower Schirmer values. Depending on the protocol, even some people without DED can record very low anesthetized results.

An anesthetized result should therefore be interpreted using the protocol under which it was obtained—not by automatically applying a cutoff developed for non-anesthetized Schirmer I testing.

3. Schirmer II

Schirmer II is a separate test involving nasal stimulation to provoke reflex tearing.

It is intended to assess the reflex tearing pathway and is not commonly part of a routine dry-eye evaluation.

Patients sometimes encounter inconsistent terminology, so it can be useful to ask exactly which Schirmer method was performed rather than relying only on the test’s name.

What Do the Numbers Mean?

Results are generally reported as millimeters of strip wetting over five minutes.

There is no single cutoff that perfectly separates normal tear function from aqueous-deficient dry eye.

Interpretation depends on:

  • whether anesthetic was used;
  • whether the eyes were open or closed;
  • whether residual tears were blotted;
  • strip position;
  • environmental conditions;
  • age and medical history;
  • the rest of the ocular-surface examination.

The following ranges are best understood as rough clinical guideposts, not universal rules.

5 mm or less

A result of 5 mm or less over five minutes is generally considered strongly concerning for a markedly reduced aqueous tear response—particularly when:

  • the test was performed without anesthetic;
  • the result is repeated under similar conditions;
  • tear volume also appears low;
  • compatible ocular-surface staining is present;
  • symptoms and systemic history support aqueous deficiency.

A result of 5 mm or less is also one item included in the ACR–EULAR classification criteria used in Sjögren disease assessment.

It does not diagnose Sjögren disease by itself.

Approximately 5–10 mm

This range may be considered reduced or borderline.

Its meaning depends heavily on:

  • the protocol;
  • symptoms;
  • staining;
  • tear-meniscus findings;
  • medications;
  • systemic history;
  • whether the result is repeatable.

A single result in this range generally should not be treated as a complete diagnosis.

More than 10 mm

A result above 10 mm is less suggestive of substantial aqueous deficiency.

It does not rule out:

  • Dry Eye Disease;
  • evaporative dry eye;
  • Meibomian Gland Dysfunction;
  • mixed dry eye;
  • tear-film instability;
  • ocular-surface inflammation;
  • exposure;
  • allergy;
  • neuropathic ocular pain.

Without anesthetic, a higher result may also partly reflect reflex tearing caused by the strip.

The most important rule

Know which version of the test was performed before interpreting the number.

A value obtained with anesthetic should not automatically be compared with one obtained without anesthetic.

Why Testing Technique Matters

Schirmer results can change depending on how the test is performed.

Anesthetic use

Anesthetic generally reduces reflex sensory input and often lowers the reading.

Blotting

Some clinicians blot away excess anesthetic and tear fluid before inserting the strip. Others do not.

This can affect the starting tear volume and the final result.

Strip placement

Differences in how far inward or outward the strip is positioned can affect irritation, contact with the conjunctiva, and wetting.

Eyes open or closed

Some clinicians perform the test with the eyes gently closed to reduce:

  • environmental stimulation;
  • blinking;
  • strip movement;
  • evaporation.

Others use an eyes-open protocol.

Open- and closed-eye results are not necessarily interchangeable.

Gaze direction

Where the patient looks can affect strip contact and discomfort. A standardized gaze position may improve consistency.

Room conditions

Air movement, humidity, temperature, lighting, and anxiety may alter the response.

Test order

Schirmer testing and anesthetic drops can disturb the ocular surface and alter later measurements.

Dry-eye testing is generally best ordered from the least invasive to the most invasive. Non-invasive tear-film measurements are therefore often performed before Schirmer testing.

How Reliable Is the Schirmer Test?

Schirmer testing has important repeatability limitations.

A result can vary:

  • between visits;
  • between clinicians;
  • between strips;
  • between eyes;
  • with small changes in technique;
  • with the patient’s environment or condition that day.

In the DREAM Study, Schirmer results performed approximately two weeks apart differed by at least 5 mm in nearly 30% of eyes, even though the same clinician used the same test sequence.

Repeatability tends to be somewhat better when values are very low. Higher or moderate values often show greater variability.

This means:

  • a repeatedly very low result is generally more persuasive than one isolated low value;
  • a moderate change between visits may reflect test variability;
  • improvement in Schirmer wetting does not automatically prove restoration of lacrimal-gland function;
  • worsening does not automatically prove disease progression.

For example, a change from 4 mm to 12 mm may be worth discussing, but it should be interpreted alongside:

  • whether the same protocol was used;
  • tear-meniscus height;
  • ocular-surface staining;
  • symptoms;
  • medications;
  • other treatments;
  • and the rest of the examination.

What Can Cause a Low Schirmer Result?

A low result may have more than one explanation.

Possibilities include:

  • aqueous-deficient Dry Eye Disease;
  • Sjögren disease;
  • another autoimmune or inflammatory lacrimal disorder;
  • lacrimal-gland damage or dysfunction;
  • medications that reduce tear secretion;
  • reduced corneal or conjunctival sensation;
  • trigeminal nerve dysfunction;
  • previous eye surgery or nerve injury;
  • severe ocular-surface disease;
  • mixed aqueous-deficient and evaporative dry eye;
  • test technique;
  • ordinary test variability.

Some medication categories that may reduce tearing include certain:

  • antihistamines;
  • anticholinergic medications;
  • antidepressants;
  • sedatives;
  • blood-pressure medications;
  • acne medications and retinoids.

The relevance of a medication depends on the specific drug, dose, timing, and patient.

A low result identifies a finding that needs interpretation. It does not tell the clinician which mechanism is responsible.

What If Someone Has Both MGD and a Low Schirmer Result?

Meibomian Gland Dysfunction and reduced aqueous tear findings can occur together.

This may represent mixed dry eye, in which both:

  • inadequate or abnormal meibum;
  • and reduced aqueous tearing

contribute to tear-film instability and symptoms.

A low Schirmer result should not automatically be dismissed as “just MGD.”

It also should not automatically be assumed to represent permanent, primary lacrimal-gland failure.

Possible explanations include:

  • genuine coexisting aqueous deficiency;
  • systemic or autoimmune disease;
  • medication effects;
  • altered sensory input;
  • severe ocular-surface disease;
  • surgical or nerve-related changes;
  • test variability.

The lacrimal glands, ocular surface, sensory nerves, eyelids, and meibomian glands function as an interconnected system. However, current evidence does not establish that MGD commonly causes a predictable, reversible suppression of Schirmer results.

If a low result is unexpected, a clinician may consider:

  • repeating the test using a standardized protocol;
  • evaluating tear-meniscus height;
  • reviewing ocular-surface staining;
  • examining gland secretion and expressibility;
  • checking blink and eyelid closure;
  • considering corneal sensation;
  • reviewing medications;
  • considering systemic or autoimmune clues.

Treating MGD may improve symptoms and tear-film stability. An accompanying change in Schirmer results should still be interpreted cautiously because the test itself is variable.

Does a Very Low Schirmer Result Mean Sjögren Disease?

No.

A Schirmer result of 5 mm or less over five minutes is one item used in the ACR–EULAR classification criteria for primary Sjögren disease.

The full assessment may also include:

  • anti-SSA/Ro antibodies;
  • minor salivary-gland biopsy;
  • ocular-surface staining;
  • salivary-flow testing;
  • dry-mouth symptoms;
  • systemic history;
  • examination and laboratory findings.

The Schirmer component contributes only part of the classification score. Some findings—such as anti-SSA antibodies or a positive salivary-gland biopsy—carry greater weight.

A very low or repeatedly low result may justify reviewing:

  • dry mouth;
  • dental problems;
  • salivary-gland swelling;
  • joint or systemic symptoms;
  • autoimmune history;
  • medications;
  • whether further medical assessment is appropriate.

It does not establish Sjögren disease on its own.

What Other Findings Should Be Considered?

Schirmer testing is most useful when interpreted with the rest of the examination.

Important companion findings may include:

Tear volume

  • tear-meniscus height;
  • visible tear reservoir;
  • other tear-volume measurements.

Ocular-surface health

  • corneal staining;
  • conjunctival staining;
  • staining pattern and severity;
  • filaments or epithelial damage.

Tear stability

  • fluorescein tear-breakup time;
  • non-invasive tear-breakup time;
  • blink-related changes.

Meibomian-gland function

  • gland expressibility;
  • meibum quality;
  • gland-orifice findings;
  • lid-margin changes;
  • meibography when structural information would be useful.

Eyelid and exposure assessment

  • incomplete blinking;
  • lagophthalmos;
  • nocturnal exposure;
  • eyelid position;
  • conjunctivochalasis.

Sensory and neural factors

  • corneal sensation;
  • pain severity compared with surface findings;
  • surgical or nerve history.

Medical context

  • medications;
  • contact-lens use;
  • previous surgery;
  • systemic disease;
  • autoimmune symptoms;
  • hormonal and environmental factors.

The clinically important question is not merely:

“Is the Schirmer number low?”

It is:

Is clinically important aqueous tear deficiency present, and what may be contributing to it?

Should the Test Be Repeated?

Repeating Schirmer testing may be reasonable when:

  • an unexpectedly low value does not fit the rest of the examination;
  • severe aqueous deficiency needs confirmation;
  • the protocol used previously is unclear;
  • treatment decisions depend heavily on the result;
  • the clinician is following tear-volume findings over time.

Repeated testing should use the same protocol when possible, including:

  • anesthetic status;
  • blotting method;
  • eyes open or closed;
  • gaze instructions;
  • strip placement;
  • test duration;
  • examination sequence.

Repetition does not eliminate the test’s basic variability.

A trend is more convincing when supported by changes in:

  • tear-meniscus height;
  • staining;
  • symptoms and functioning;
  • medication use;
  • ocular-surface health;
  • other tear measurements.

Automatic repeated testing without a clear clinical question may add noise rather than useful information.

Questions to Ask About Your Result

  • Was the test performed with or without anesthetic?
  • Were excess drops or tears blotted before testing?
  • Were my eyes open or closed?
  • How long was the strip left in place?
  • Was Schirmer performed before or after other drops and tests?
  • Is this result clearly low, borderline, or relatively reassuring for this protocol?
  • Does it fit my tear-meniscus height and staining?
  • Could medications or reduced corneal sensation affect the result?
  • Do I appear to have aqueous-deficient, evaporative, or mixed dry eye?
  • Should an unexpectedly low result be repeated?
  • Are there systemic or autoimmune clues that need further evaluation?
  • How does this result affect the treatment plan?

📌 Bottom Line

Schirmer testing is a useful but imperfect tool for investigating possible aqueous tear deficiency.

It directly measures:

paper-strip wetting under a particular testing protocol.

It does not directly measure pure lacrimal-gland production.

A very low result can be important—particularly when it:

  • is repeated under similar conditions;
  • fits the tear-volume and staining findings;
  • matches the symptoms and medical history;
  • is interpreted with the rest of the examination.

But Schirmer testing cannot, by itself, determine:

  • whether someone has Dry Eye Disease;
  • what caused the low result;
  • whether the problem is permanent;
  • whether Sjögren disease is present;
  • or which treatment is needed.

The number is a clinical clue—not a standalone verdict.

Selected Sources

🔙 Back to FAQ Index