Schirmer Tear Test (STT) in Dogs, Cats, and Other Pets
Southern Ocean Animal Hospital — Ophthalmology Services
(Specialized Care & Diagnostics)
TL;DR (Too Long; Didn’t Read)
The Schirmer Tear Test (STT) measures how much tear fluid your pet’s eyes produce. Tears protect the eye’s surface, keep it lubricated, and support corneal health. Low tear production indicates dry eye disease (keratoconjunctivitis sicca), a painful condition that can cause redness, thick discharge, corneal ulcers, and even blindness if untreated.
At Southern Ocean Animal Hospital, Daniel N. Pascetta, DVM performs the STT using standardized testing strips and advanced ophthalmic evaluation tools to quickly and accurately diagnose tear deficiencies in dogs, cats, and other pets. Early detection allows for effective treatment, comfort, and long-term eye protection.
ELI5 (Explain Like I’m Five)
Your pet’s eyes make tears so the surface stays clean, smooth, and healthy.
If they don’t make enough tears, the eye gets dry — like skin getting cracked without lotion.
The Schirmer Tear Test is like putting a tiny piece of soft paper under the eyelid to see how fast it gets wet.
If it barely gets wet, the pet has dry eyes and needs help.
1. Introduction: Why Tears Matter for Pets
Tears are much more than simple moisture.
They form a protective shield over the cornea and keep the eye functioning normally.
Tears:
- Wash away debris
- Prevent infections
- Carry oxygen to the cornea
- Support healing
- Maintain comfortable blinking
- Protect vision
When tear production decreases, the eye becomes irritated, painful, and vulnerable to infection and injury.
This is why the Schirmer Tear Test is a cornerstone diagnostic tool in veterinary ophthalmology.
2. What Is the Schirmer Tear Test?
The Schirmer Tear Test (STT) measures the baseline tear production in dogs, cats, rabbits, and exotic species.
The test uses a standardized sterile paper strip placed inside the lower eyelid for 60 seconds.
After one minute, the strip shows how many millimeters of tear fluid were produced.
It is:
- Quick
- Painless
- Reliable
- Essential for diagnosing dry eye (KCS) and related disorders
At Southern Ocean Animal Hospital, the STT is routinely performed when pets show signs of:
- Red eyes
- Thick or sticky discharge
- Squinting
- Cloudy corneas
- Chronic eye infections
- Pigmentation changes
- Ulcers
- Tear staining
3. Why Pets Need the Schirmer Tear Test
The STT is primarily used to diagnose keratoconjunctivitis sicca (KCS) — commonly known as dry eye.
Left untreated, dry eye can lead to:
- Chronic irritation
- Persistent infections
- Corneal scratches
- Ulceration
- Scarring
- Pain
- Potential blindness
Since pets cannot tell you their eyes hurt, the STT gives veterinarians an objective measurement.
Common conditions detected with the STT:
- Immune-mediated dry eye
- Drug-induced tear suppression
- Neurological disorders
- Cherry eye aftermath
- Viral infections (e.g., distemper)
- Post-surgical complications
- Breed-related tear deficiencies
- Trauma-related nerve damage
4. Understanding the Tear Film: The Foundation of Eye Health
The tear film has three layers:
A. Lipid Layer (Outer Layer)
Produced by the meibomian glands.
Prevents tear evaporation.
B. Aqueous Layer (Middle Layer)
Produced by the lacrimal glands.
Carries:
- Oxygen
- Nutrients
- Antimicrobial compounds
This is the layer measured by the Schirmer Tear Test.
C. Mucin Layer (Inner Layer)
Helps tears adhere to the cornea.
A deficiency in any of these layers causes discomfort, inflammation, and disease.
5. How the Schirmer Tear Test Is Performed
Step 1 — Preparation
The vet ensures the pet is calm and held gently.
Topical anesthetic is not used because it artificially lowers tear production.
Step 2 — Placing the Test Strip
- A sterile strip is bent at a notch
- Inserted into the lower eyelid
- The pet closes its eye naturally over the strip
Step 3 — One-Minute Timer
Tear fluid travels up the strip.
Most pets tolerate this exceptionally well.
Step 4 — Reading the Result
After 60 seconds, the measurement is recorded in millimeters (mm).
Step 5 — Documenting & Comparing
Dr. Pascetta compares results with breed norms and the other eye.
6. Normal Schirmer Tear Test Values
Dogs
- Normal: 15–25 mm/min
- Borderline: 10–14 mm/min
- Diagnostic for dry eye: 0–10 mm/min
Cats
Cats often have lower baseline tears:
- Normal: 10–15 mm/min
- Borderline: 7–10 mm/min
- Diagnostic for dry eye: 0–7 mm/min
Other species
Values vary, but the principles remain identical.
7. Common Conditions Identified Through STT
A. Keratoconjunctivitis Sicca (KCS)
Most common cause of low tear production.
Signs include:
- Thick mucus
- Redness
- Squinting
- Cloudiness
- Pigmentation changes
- Frequent infections
B. Neurologic Dry Eye
Damage to nerves that regulate blinking or tear production.
C. Immune-Mediated Disease
The immune system attacks tear glands.
D. Medication-Induced Tear Suppression
Common culprits:
- Sulfa antibiotics
- Certain anesthetics
- Atropine
E. Viral Disease
Examples:
- Canine distemper
- Feline herpesvirus
F. Breed-Related Issues
Some breeds produce fewer tears naturally:
- Shih Tzu
- Cocker Spaniel
- Bulldog
- Pug
- Pekingese
- Lhasa Apso
G. Post-Surgical Effects
Especially after eyelid or third eyelid procedures.
8. Additional Tests Used Alongside STT
A. Fluorescein Stain
Checks for corneal ulcers.
B. Tonometry
Measures intraocular pressure (glaucoma screening).
C. Tear Film Break-Up Time (TBUT)
Evaluates tear stability.
D. Schirmer Tear Test II
Performed after anesthetic to measure baseline secretion minus reflex tears.
E. Complete Ophthalmic Examination
Slit lamp, ophthalmoscopy, and retinal evaluation.
9. Example Scenario: A Dog With Chronic Eye Discharge
A 6-year-old Shih Tzu named Bella presents with:
- Thick yellow discharge
- Red eyes
- Frequent infections
STT Results:
- Right eye: 6 mm/min
- Left eye: 8 mm/min
Diagnosis:
Moderate immune-mediated KCS.
Treatment Plan:
- Cyclosporine ointment
- Lubricating drops
- Warm compresses
- Antibiotics for secondary infection
Outcome:
Within 4 weeks, tearing normalized and redness resolved.
10. Timeline of Diagnosis and Treatment
Day 1: Schirmer Tear Test → Diagnosis → Medications started
Week 1: Noticeable improvement in comfort
Week 4: Retest to evaluate progress
Ongoing: Regular monitoring every 6–12 months
Dry eye is chronic but well-managed with proper care.
11. What-If Situations
What if dry eye is ignored?
- Pain
- Corneal ulcers
- Long-term scarring
- Permanent blindness
What if symptoms seem mild?
Early stages are often subtle — yet damage is already occurring.
What if only one eye shows symptoms?
The other eye is usually at risk; STT helps detect early changes.
What if your pet becomes difficult during testing?
Southern Ocean Animal Hospital uses:
- Low-stress handling
- Feline-friendly techniques
- Gentle restraint
- Helpful distractions
- Fear-free strategies
12. Techniques & Tools Used by Daniel N. Pascetta, DVM
Dr. Pascetta blends advanced diagnostic tools with years of medical experience to ensure accuracy and comfort.
His diagnostic approach includes:
- High-precision Schirmer Tear Test strips
- Slit-lamp biomicroscopy
- Fluorescein staining
- Tonometry (pressure measurement)
- In-depth corneal and conjunctival assessment
- Full retinal and optic nerve evaluation
Dr. Dan is proficient in recognizing subtle tear film abnormalities, distinguishing KCS from infections, allergies, and neurologic disorders, and creating personalized treatment plans for each pet.
13. Treatment Options for Low Tear Production
A. Immunomodulatory Medications
Cyclosporine or tacrolimus help restore tear production.
B. Lubricating Drops & Gels
Protect the cornea and relieve pain.
C. Antibiotics
Used when infections are present.
D. Anti-inflammatory Medications
Reduce swelling and irritation.
E. Surgical Options
In severe, unresponsive cases:
- Parotid duct transposition
F. Environmental Management
- Humidifiers
- Reducing irritants
- Gentle cleaning of discharge
14. Service Area & Reputation
Southern Ocean Animal Hospital proudly serves:
- Tuckerton
- Manahawkin
- Barnegat
- Waretown
- Little Egg Harbor
- LBI (all towns)
- Forked River
- Lacey Township
- Galloway
- Absecon
- Other Jersey Shore and Ocean County regions
Pet owners frequently travel 35–60 minutes or more because of the hospital’s reputation for:
- Advanced ophthalmic diagnostics
- Precise testing
- Comprehensive treatment plans
- Trusted veterinary expertise
- Compassionate, fear-free handling
15. Glossary of Terms
STT: Schirmer Tear Test
KCS: Keratoconjunctivitis sicca, or dry eye
Mydriasis: Pupil dilation
Tonometry: Measurement of eye pressure
Conjunctiva: Pink tissue lining eyelids
Cornea: Clear outer surface of the eye
Tear film: Protective moisture layer
Immunomodulators: Medications regulating the immune system
16. Schedule an Appointment
If your pet has red eyes, thick discharge, squinting, or seems uncomfortable, the Schirmer Tear Test may be essential for diagnosing and preventing painful eye disease.
Call Southern Ocean Animal Hospital during business hours to schedule a full ophthalmic exam with Dr. Daniel N. Pascetta, DVM. Early testing means fast relief — and long-term protection for your pet’s vision.