Why do eyes water on the outside underneath?

Causes of Eyes Watering on the Outside Underneath

Eyes watering on the outside underneath is most commonly caused by dry eye syndrome, which paradoxically leads to excess tearing as a compensatory mechanism, or by ocular surface disorders affecting the tear drainage system.

Dry Eye Disease as a Primary Cause

Dry eye disease (DED) is a multifactorial condition that often presents with excessive tearing, particularly at the outer corners of the eyes. This occurs through the following mechanisms:

• Reflex tearing: When the ocular surface becomes irritated due to dryness, the lacrimal gland produces excess tears as a compensatory mechanism 1, 2
• Tear drainage issues: Inflammation can affect the normal drainage of tears through the puncta and nasolacrimal system, causing overflow 1
• Tear film instability: Poor quality tears that evaporate too quickly trigger production of more tears 1, 2

Contributing Factors to Dry Eye and Excessive Tearing

1. Meibomian Gland Dysfunction (MGD)

   • Causes evaporative dry eye by affecting the lipid layer of tears
   • Results in tear film instability and compensatory tearing 1

2. Blepharitis and Lid Margin Disease

   • Inflammation of eyelids leads to poor tear quality
   • Can cause both irritation and excess tearing 1

3. Environmental and Lifestyle Factors

   • Reduced humidity, air conditioning, heating
   • Increased screen time (reduces blink rate)
   • Wind exposure 1, 2

4. Medication-Related Causes

   • Systemic medications: diuretics, antihistamines, anticholinergics, antidepressants, retinoids
   • Topical eye medications with preservatives (especially with frequent use) 1, 2

5. Rosacea

   • Can exacerbate dry eye symptoms and cause ocular surface inflammation
   • Often overlooked, especially in children 1

Other Causes of Watering Eyes

1. Contact Lens-Related Issues

   • Mechanical irritation, chronic hypoxia, or preservative reactions
   • Can lead to giant papillary conjunctivitis with watery discharge 1

2. Floppy Eyelid Syndrome

   • Upper eyelid edema and laxity
   • Causes chronic ocular irritation and tearing 1

3. Giant Fornix Syndrome

   • Affects elderly women with large superior fornix
   • Presents with chronic mucopurulent discharge and tearing 1

4. Dupilumab-Related Ocular Surface Disorders (DROSD)

   • In patients taking dupilumab for atopic dermatitis
   • Can cause conjunctivitis and excessive tearing 1

Diagnostic Considerations

When evaluating watering eyes, look for:

• Tear film quality: Using fluorescein, rose bengal, or lissamine green staining 1
• Tear production: Schirmer test (less than 10mm wetting in 5 minutes suggests abnormality) 1
• Lid position and function: Check for ectropion, entropion, or incomplete blinking 2
• Punctal patency: Ensure tear drainage system is functioning properly
• Corneal sensation: Using a cotton tip applicator to assess for neurotrophic keratopathy 1

Management Approach

1. For Dry Eye-Related Tearing:

   • Artificial tears without preservatives for mild cases
   • Lid hygiene measures for associated blepharitis
   • Warm compresses followed by eyelid massage to unblock oil glands 1

2. For Medication-Induced Tearing:

   • Consider reducing frequency of preserved eye drops
   • Evaluate systemic medications that may contribute to dry eye 1

3. For Inflammatory Causes:

   • Topical anti-inflammatory treatments like tacrolimus 0.1% ointment for lid margins
   • Ciclosporin eyedrops for severe cases not responding to tear substitutes 1

4. Environmental Modifications:

   • Increase humidity in living/working spaces
   • Take regular breaks during screen time
   • Use protective eyewear in windy conditions 2

Important Considerations

• Watering eyes significantly impact quality of life and can lead to depressive symptoms 3
• Early intervention is important as chronic inflammation can lead to corneal damage 2
• Children can develop watering eyes due to congenital conditions, autoimmune diseases, or medication effects 1
• Ophthalmology referral is warranted for persistent symptoms not responding to initial management 1

Remember that paradoxical tearing from dry eye is a common and often misunderstood phenomenon. Treating the underlying dry eye condition often resolves the excessive tearing that bothers patients.