Causes of Excessive Tearing in One Eye
Excessive tearing in one eye (epiphora) is most commonly caused by a blockage in the tear drainage system or increased tear production due to ocular surface irritation. 1
Primary Causes
Tear Drainage Problems
- Nasolacrimal duct obstruction - blockage in the tear drainage system preventing normal tear outflow 2
- Punctal stenosis - narrowing of the tear duct opening 1
- Eyelid malposition (ectropion, entropion) affecting proper tear drainage 1
Ocular Surface Disorders
- Blepharitis - inflammation of the eyelid margins causing irritation and reflex tearing 1
- Dry eye syndrome - paradoxically causes excessive tearing as a reflex response to ocular surface irritation 1, 3
- Meibomian gland dysfunction - affects tear film stability leading to evaporative dry eye and reflex tearing 1
Other Common Causes
- Conjunctivitis - inflammation of the conjunctiva causing irritation and increased tear production 1
- Foreign body sensation - stimulates reflex tearing 1
- Corneal abrasion or injury - triggers protective tearing response 1
- Allergic reactions - causing eye irritation and increased tear production 1
Diagnostic Approach
History
- Determine if symptoms include burning, irritation, redness, or foreign body sensation (suggesting ocular surface disease) 1
- Note time of day when symptoms worsen (morning worsening suggests blepharitis; worsening later in day suggests aqueous-deficient dry eye) 1
- Ask about environmental triggers (smoke, allergens, wind, low humidity) 1
- Inquire about screen time habits which may reduce blink rate 1
Examination
- Assess eyelid position and function for malposition or incomplete closure 1, 4
- Examine eyelid margins for signs of blepharitis (crusting, redness, thickening) 1
- Check meibomian gland orifices for capping, pouting or obstruction 1
- Evaluate tear film break-up time to assess tear film stability 1
- Perform fluorescein staining to detect corneal or conjunctival epithelial defects 1
- Consider Schirmer test to measure aqueous tear production 1, 5
Specialized Testing
- Fluorescein dye disappearance test to assess tear drainage function 1, 2
- Tear osmolarity testing to evaluate for dry eye disease 1
- Lacrimal scintigraphy for precise localization of tear drainage obstruction 2
Management
For Tear Drainage Problems
- Nasolacrimal duct probing or dacryocystorhinostomy for obstruction 6
- Punctal dilation for punctal stenosis 6
- Eyelid surgery to correct malposition affecting tear drainage 4
For Ocular Surface Disease
- Eyelid hygiene for blepharitis (warm compresses, lid scrubs) 1
- Artificial tears for mild dry eye symptoms 1, 3
- Anti-inflammatory treatments (cyclosporine, lifitegrast) for moderate to severe dry eye 1, 3
- Punctal plugs for severe aqueous-deficient dry eye 1, 3
For Allergic or Inflammatory Causes
- Antihistamine eye drops for allergic conjunctivitis 1
- Topical steroids for inflammatory conditions (short-term use) 1, 3
- Environmental modifications to reduce exposure to irritants 1
Important Considerations
- Unilateral tearing should raise suspicion for a localized problem in the affected eye 1, 2
- Paradoxically, dry eye is a common cause of excessive tearing due to reflex tearing response 1, 3
- Conditions like rosacea may present with ocular symptoms before cutaneous manifestations 1
- Consider systemic conditions (Sjögren's syndrome, sarcoidosis) if other symptoms are present 1