Key Facts

Dry eye disease is a multifactorial disease of the ocular surface characterised by loss of homeostasis of the tear film, leading to ocular symptoms including discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface. It is one of the most common reasons for ophthalmology and optometry consultations.

Epidemiology

• Prevalence: 5-30% depending on definition and population studied
• More common in females (1.5-2× risk) and postmenopausal women
• Prevalence increases significantly with age (>50 years)
• Screen time and environmental factors contribute to rising prevalence

Aetiology

• Evaporative dry eye (most common, >85%): meibomian gland dysfunction, blepharitis, reduced blink rate (screen use), environmental (low humidity, air conditioning)
• Aqueous-deficient dry eye: Sjögren syndrome (primary or secondary), lacrimal gland infiltration, age-related gland atrophy
• Medications: antihistamines, tricyclic antidepressants, beta-blockers, diuretics, oral contraceptives, isotretinoin
• Systemic disease: rheumatoid arthritis, SLE, sarcoidosis, thyroid eye disease, graft-versus-host disease
• Iatrogenic: LASIK, cataract surgery, contact lens wear, radiation

Pathophysiology

• Tear film has three layers: lipid (meibomian glands), aqueous (lacrimal gland), and mucin (goblet cells)
• Loss of any component leads to tear film instability
• Hyperosmolarity of tears is the central mechanism driving ocular surface inflammation
• Inflammatory cascade (IL-1, TNF-α, MMP-9) damages epithelial cells and goblet cells
• Creates a vicious cycle of instability → inflammation → further damage

Symptoms

• Gritty, sandy, foreign body sensation
• Burning or stinging
• Paradoxical tearing (reflex tearing due to ocular surface irritation)
• Photophobia
• Blurred vision (fluctuating, improves with blinking)
• Tired eyes, difficulty with prolonged reading/screen use
• Symptoms worse in dry environments, with air conditioning, or wind

Examination Findings

• Reduced tear meniscus height
• Conjunctival hyperaemia
• Punctate corneal staining with fluorescein
• Meibomian gland dysfunction: capped or blocked gland orifices, frothy tears, lid margin irregularity
• Blepharitis: crusting, collarettes

Red Flags

• Unilateral dry eye (consider lacrimal gland tumour, nerve palsy)
• Associated with xerostomia and parotid swelling (Sjögren syndrome)
• Filamentary keratitis (severe disease)
• Corneal ulceration or perforation (severe untreated disease)
• Young patient with severe disease (investigate for Sjögren syndrome)

Bedside

• Schirmer test: filter paper in lower fornix for 5 minutes
  • Normal: >15mm; Dry eye: <10mm; Severe: <5mm
• Tear break-up time (TBUT): time for first dry spot after blink
  • Normal: >10 seconds; Abnormal: <10 seconds
• Fluorescein staining: punctate epithelial erosions
• Meibomian gland expression assessment
• Lissamine green staining: conjunctival damage

Bloods

• Anti-Ro (SSA) and anti-La (SSB) antibodies: if Sjögren syndrome suspected
• ANA, rheumatoid factor
• ESR, CRP
• Immunoglobulins

Imaging

• Meibography: infrared imaging of meibomian gland structure
• USS parotid glands if Sjögren syndrome suspected

Special Tests

• OSDI questionnaire (Ocular Surface Disease Index): validated symptom scoring
• Tear osmolarity measurement (>308 mOsm/L = abnormal)
• MMP-9 point-of-care testing (InflammaDry)
• Labial salivary gland biopsy: focal lymphocytic sialadenitis (Sjögren syndrome)

Non-pharmacological

• Lid hygiene: warm compresses (10 minutes BD) + lid massage for meibomian gland dysfunction
• Environmental modification: humidifier, reduce screen time, take regular breaks (20-20-20 rule)
• Blink exercises
• Omega-3 fatty acid supplementation (evidence mixed; DREAM trial showed no benefit over placebo)
• Moisture chamber glasses

Pharmacological

• Step 1: Artificial tears (hypromellose 0.3% QDS, carbomer 980 gel PRN, sodium hyaluronate 0.1-0.2%)
  • Preservative-free formulations preferred for frequent use (>4× daily)
• Step 2: Topical anti-inflammatory — ciclosporin 0.1% (Ikervis) OD at bedtime (NICE TA369 for severe dry eye)
  • Lifitegrast 5% (Xiidra) — available in some settings
• Step 3: Short courses of topical corticosteroids (fluorometholone 0.1% or loteprednol 0.5%) under specialist supervision
• Oral tetracyclines (doxycycline 50-100mg OD for 3 months) for meibomian gland dysfunction (anti-inflammatory, not antimicrobial at this dose)
• Oral pilocarpine 5mg TDS for Sjögren-related aqueous deficiency

Surgical

• Punctal plugs: silicone or collagen plugs to reduce tear drainage (for aqueous deficiency)
• Punctal cautery for permanent occlusion
• Intense pulsed light (IPL) therapy for meibomian gland dysfunction
• Amniotic membrane transplant for severe ocular surface disease
• Tarsorrhaphy for exposure keratopathy

Referral Criteria

• Ophthalmology referral if not responding to first-line artificial tears after 4-6 weeks
• Rheumatology referral if Sjögren syndrome suspected
• Urgent referral if corneal complications (ulceration, thinning)

• Dry eye disease is typically a chronic condition requiring long-term management
• Mild-moderate disease: well controlled with artificial tears in most patients
• Severe disease: significant impact on quality of life; may require combination therapy
• Sjögren-related dry eye tends to be more severe and progressive
• Sight-threatening complications (corneal ulceration, perforation) are rare with appropriate treatment
• Meibomian gland dysfunction may improve with consistent lid hygiene
• Quality of life impact comparable to moderate-severe angina (studies)

TFOS DEWS II Severity Grading

Key Medications Causing Dry Eye