Eye Diseases > Cornea

Dry Eye Syndrome

Evidence-based assessment and management of dry eye disease (DED). Comprehensive guide covering etiology, pathogenesis, classification, TFOS DEWS II diagnostic criteria, and stepwise management protocols for optometry practice.

Dry Eye Syndrome (DES), also termed Dry Eye Disease (DED) or keratoconjunctivitis sicca (KCS), is a multifactorial chronic condition of the ocular surface. The TFOS DEWS II 2017 consensus defines it as "a loss of homeostasis of the tear film, accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play aetiological roles."

It is one of the most common conditions encountered in optometry and ophthalmology practice, with a global prevalence estimated between 5–50% depending on the diagnostic criteria and population studied. DES significantly impacts quality of life, visual function, and ocular surface integrity.

5–50%

Global Prevalence

depending on criteria used

Evaporative

Most Common Type

80–90% MGD-driven

Female >50

Peak Demographics

post-menopausal, Asian ethnicity

Aqueous-Deficient Dry Eye (ADDE)

Sjögren Syndrome (SS): Primary SS (isolated exocrine gland disease) or Secondary SS (associated with RA, SLE, primary biliary cholangitis) — autoimmune lymphocytic infiltration of lacrimal glands
Non-Sjögren lacrimal gland disease: Sarcoidosis, lymphoma, lacrimal gland infiltration, amyloidosis
Lacrimal gland obstruction: Cicatrising conjunctival disease, trachoma, chemical burns, Stevens-Johnson syndrome
Reflex block: Corneal anaesthesia (neurotrophic keratopathy), systemic medications (anticholinergics, beta-blockers), contact lens wear
Drug-induced: Antihistamines, antidepressants (TCAs/SSRIs), antipsychotics, diuretics, isotretinoin, oral contraceptives, hormone replacement therapy

Evaporative Dry Eye (EDE)

Meibomian gland dysfunction (MGD): Most common cause of EDE (80–90% of all DES) — obstructive or hyposecretory MGD leading to deficient lipid layer and increased tear evaporation
Lid-related: Incomplete blink, lagophthalmos, ectropion, wide palpebral aperture (thyroid eye disease)
Low blink rate: Prolonged screen use, deep concentration tasks, Parkinson's disease
Contact lens wear: Increased evaporation, altered lipid layer, reduced mucin production
Allergic conjunctivitis: Inflammatory goblet cell loss, mucin deficiency
Vitamin A deficiency: Goblet cell loss, xerophthalmia, bitot's spots

Mixed Mechanism

The majority of DES patients present with a combination of aqueous deficiency and evaporative components. Rarely is a pure subtype identified in clinical practice.

Core Mechanism: The Vicious Cycle

Tear film instability leads to tear hyperosmolarity, which activates MAP kinase and NF-κB inflammatory signalling cascades. This produces pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) and matrix metalloproteinases (MMP-9), causing conjunctival and corneal epithelial cell apoptosis, goblet cell loss, and reduced mucin production — further destabilising the tear film and perpetuating the cycle.

MGD / Evaporative Pathway

Posterior lid margin disease → obstructed meibomian gland orifices → altered lipid secretion (increased viscosity, altered composition)
Deficient/abnormal lipid layer → increased aqueous evaporation rate (up to 4× normal)
Compensatory increase in aqueous secretion initially, followed by lacrimal gland fatigue
Hyperosmolarity → inflammation → further meibomian gland atrophy (self-perpetuating)

Neurogenic Pathway

Chronic ocular surface inflammation impairs corneal nerve density and sensitivity
Reduced afferent corneal sensation → decreased lacrimal reflex secretion → worsened aqueous deficiency
Reduced blink frequency and completeness → increased evaporation and ocular surface exposure
Neurotrophic keratopathy in severe cases: complete loss of corneal sensation, impaired epithelial healing

Goblet Cell & Mucin Loss

Conjunctival goblet cells produce MUC5AC, the primary gel-forming mucin of the tear film. Hyperosmolarity and inflammation cause goblet cell apoptosis, reducing mucin secretion, wetting capacity, and tear film stability — directly shortening tear break-up time (TBUT).

The TFOS DEWS II (2017) classification provides the current gold standard framework, replacing the older aqueous-deficient vs. evaporative binary with a more nuanced understanding of overlapping mechanisms.

Aqueous-Deficient DED (ADDE)

Sjögren Syndrome-associated DED (SS-DED)

Primary SS or Secondary SS (RA, SLE, primary biliary cholangitis). Autoimmune lacrimal gland destruction. Most severe form of ADDE.

Non-Sjögren's ADDE

Lacrimal gland disease (sarcoid, lymphoma), lacrimal duct obstruction (cicatricial conjunctivitis, trachoma, chemical burns, SJS), reflex block (neurotrophic keratopathy, contact lens wear), drug-induced (systemic medications).

Evaporative DED (EDE)

Intrinsic EDE

Meibomian gland dysfunction (obstructive MGD most common), lid-related abnormalities (incomplete blink, lagophthalmos, wide palpebral aperture), low blink rate (digital screen use, Parkinson's disease).

Extrinsic EDE

Contact lens wear (altered lipid layer, increased evaporation), ocular surface disease (allergic conjunctivitis — goblet cell loss), vitamin A deficiency (xerophthalmia), topical medication toxicity (preservatives).

Severity Grading (TFOS DEWS II)

MildTBUT >7sSchirmer >10mmAbsent/mild stainingOSDI 13–22

ModerateTBUT 3–7sSchirmer 5–10mmMild-moderate stainingOSDI 23–32

SevereTBUT <3sSchirmer <5mmModerate-severe stainingOSDI >33

Patient-Related Factors

Age (>50 years): Reduced lacrimal gland secretory capacity, meibomian gland atrophy, decreased goblet cell density
Female sex: Androgen deficiency (especially post-menopause) impairs meibomian gland function and lacrimal secretion; hormonal fluctuations across menstrual cycle
Asian ethnicity: Higher prevalence of MGD, shorter tear film break-up times in epidemiological studies
Menopause / androgen deficiency: Strong association; androgen receptors present on meibomian and lacrimal glands

Behavioural & Environmental Factors

Prolonged screen use: Reduces blink rate by up to 66%; incomplete blinks; increased exposure area
Contact lens wear: Alters tear film dynamics, increases evaporation, reduces mucin layer, hypoxia-mediated changes
Low humidity environments: Air conditioning, aircraft cabins, heated offices significantly increase evaporative loss
Smoking: Oxidative damage to meibomian glands; toxic to ocular surface epithelium
Vitamin A / omega-3 deficiency: Essential for goblet cell function and mucin production

Iatrogenic Factors

Refractive surgery (LASIK): Corneal nerve severing reduces afferent loop of lacrimal reflex; often induces transient-to-chronic DES
Systemic medications: Antihistamines, antidepressants (TCAs, SSRIs, SNRIs), antipsychotics, diuretics, beta-blockers, isotretinoin, oral contraceptives, hormone replacement therapy
Topical preservatives (BAK): Benzalkonium chloride in topical glaucoma medications is directly toxic to the ocular surface and meibomian glands
Prior eyelid surgery: Can disrupt meibomian gland architecture, alter lid margin position

Systemic Disease-Related

Sjögren syndrome, rheumatoid arthritis, SLE, graft-versus-host disease, thyroid eye disease, diabetes mellitus, Parkinson's disease, rosacea

Tear Film Assessment

Fluorescein TBUT <10s (significant <5s) — instability of aqueous layer; NIBUT by corneal topographer preferred (non-invasive)
Reduced tear meniscus height <0.2mm — assessed at inferior lid margin with slit lamp or OCT
Tear osmolarity ≥308 mOsm/L (or inter-eye difference >8 mOsm/L) — TearLab or i-Pen osmometer; most specific objective biomarker
Lipid layer grading: Thin/absent lipid layer visible on specular reflection (Guillon grading: 1 = thick, 5 = absent)

Ocular Surface Staining

Fluorescein staining: Punctate epithelial erosions (PEEs) — corneal and conjunctival; Oxford grading 0–5 or NEI grading; inter-palpebral distribution typical
Lissamine green / Rose Bengal staining: Conjunctival staining; van Bijsterveld grading 0–9; marks devitalised cells
Lid wiper epitheliopathy (LWE): Lissamine green staining of upper/lower lid wiper margin — sensitive sign of DES
Corneal filaments: Mucous strands adherent to corneal surface — filamentary keratitis in severe DES

Lacrimal Function Tests

Schirmer I test (without anaesthesia): ≤10mm/5min abnormal; ≤5mm/5min severe; measures basal + reflex secretion
Schirmer II test (with anaesthesia): ≤5mm/5min; measures basal secretion only
Phenol red thread test: ≤10mm/15s; well-tolerated alternative to Schirmer

Meibomian Gland Assessment

Meibography (non-contact infrared): Meibomian gland dropout graded 0–3 per lid (Meiboscore); LipiView / Keratograph 5M
Lid margin: Telangiectasia, keratinisation, anterior/posterior displacement of mucocutaneous junction, plugged orifices
Meibomian gland expressibility: Digital pressure or Meibomian Gland Evaluator; grade 0–3; toothpaste-like secretion typical of obstructive MGD
MMP-9 (InflammaDry): Point-of-care test; positive ≥40 ng/mL — indicates ocular surface inflammation

Common Presenting Symptoms

Burning and stinging: Most common; worse in evaporative DES; correlates with osmolarity and inflammation
Foreign body / gritty sensation: Sandy/gritty feeling; associated with punctate epithelial erosions and reduced mucin
Fluctuating or blurred vision: Vision clears transiently with blinking; reduced TFBUT causes optical degradation between blinks
Photophobia: Corneal nerve irritation and inflammation; often marked in severe DES or filamentary keratitis
Paradoxical epiphora (tearing): Reflex hypersecretion from lacrimal gland in response to ocular surface irritation — does not indicate adequate tear film
Contact lens intolerance: Reduced wear time, discomfort, lens dehydration, reduced visual performance
Difficulty with sustained visual tasks: Reading, driving, computer use; symptoms worsen with prolonged visual demand

Symptom Pattern by Subtype

Aqueous-Deficient DES

• Symptoms worse in afternoon / evening
• Prominent burning and stinging
• Symptoms worsen in dry, windy conditions
• Marked relief with artificial tears
• Often associated with dry mouth (SS)

Evaporative (MGD-driven) DES

• Symptoms worse with screen use / reading
• Morning lid margin crusting / discharge
• Itching and lid margin irritation
• Less marked response to artificial tears alone
• Often associated with rosacea / seborrhoea

Validated Symptom Questionnaires

OSDI (Ocular Surface Disease Index): 12-item questionnaire; score 0–100; ≥13 = dry eye symptoms (mild 13–22, moderate 23–32, severe ≥33)
DEQ-5 (Dry Eye Questionnaire): 5-item; score ≥6 = positive for DES; quick screening tool
SPEED (Standard Patient Evaluation of Eye Dryness): 8-item; widely used in contact lens practice

Corneal Complications

Punctate epithelial erosions (PEEs): Superficial epithelial defects from desiccation; if recurrent, progresses to deeper pathology
Filamentary keratitis: Twisted mucous-epithelial strands adherent to cornea; painful, causes foreign body sensation; hallmark of severe DES
Recurrent corneal erosion syndrome: Compromised epithelial adhesion complexes from chronic desiccation and inflammation
Sterile corneal ulceration: Peripheral or central; primarily in Sjögren's or severe ADDE; risk of perforation in advanced cases
Corneal vascularisation: Neovascularisation from chronic hypoxia and inflammation; compromises optical quality
Corneal scarring and opacification: End-stage complication; permanent vision loss; may require corneal transplantation

Infectious Complications

Bacterial keratitis: Compromised epithelial barrier increases susceptibility; especially in contact lens wearers with DES
Blepharitis and hordeolum: MGD-associated DES predisposes to lid margin infection
Recurrent conjunctivitis: Impaired mucosal immunity from reduced IgA and lysozyme in deficient tears

Functional & Quality of Life Impact

Impaired visual performance: Higher-order aberrations from irregular tear film; reduced contrast sensitivity; symptoms worsen over a day's use
Blepharospasm: Chronic pain-induced involuntary lid closure; particularly debilitating
Depression and anxiety: Chronic pain condition with significant quality-of-life burden equivalent to moderate angina or dialysis patients in studies
Inability to wear contact lenses: Social, occupational, and sport-related functional impairment
Reduced surgical success: DES impairs outcomes of cataract, refractive, and glaucoma surgery if untreated pre-operatively

Autoimmune & Connective Tissue Disease

Sjögren Syndrome (Primary & Secondary): DES is a cardinal feature; secondary SS associated with RA, SLE, primary biliary cholangitis, polymyositis. Screen with anti-SSA/Ro and anti-SSB/La antibodies; refer for rheumatology workup
Rheumatoid Arthritis (RA): Secondary SS in 30–50%; also independent lacrimal gland disease; peripheral ulcerative keratitis risk
Systemic Lupus Erythematosus (SLE): Secondary SS; vasculitic ocular manifestations; hydroxychloroquine (Plaquenil) use can paradoxically worsen DES
Graft-versus-Host Disease (GvHD): Post-haematopoietic stem cell transplantation; severe cicatrising ocular surface disease; major indication for scleral lenses and autologous serum
Scleroderma / polymyositis / primary biliary cholangitis: Associated with secondary SS and lacrimal gland disease

Endocrine & Metabolic

Thyroid Eye Disease (Grave's / Hashimoto's): Lagophthalmos and proptosis cause exposure keratopathy; reduced blink rate; eyelid retraction widens palpebral aperture
Diabetes Mellitus: Peripheral neuropathy reduces corneal sensation (neurotrophic component); impaired lacrimal gland innervation; reduced tear secretion; impaired epithelial healing
Menopause / androgen deficiency: Reduced androgen levels directly impair meibomian gland lipid secretion and lacrimal gland function; strong epidemiological link

Neurological

Parkinson's Disease: Dopaminergic deficit reduces blink rate (2–3 blinks/min vs normal 15–20/min); severe evaporative DES; reduced lacrimal reflex
Facial nerve palsy (CN VII): Lagophthalmos → exposure keratopathy; reduced reflex blink; requires urgent management
Trigeminal nerve disease (CN V): Reduced corneal sensation → neurotrophic keratopathy; absent protective blink reflex

Dermatological

Rosacea: Ocular rosacea in 60% of patients; MGD-driven DES; telangectasia of lid margins; responds well to oral doxycycline and IPL
Seborrhoeic dermatitis: Anterior blepharitis with secondary MGD and DES; dandruff-like lid scaling
Vitamin A deficiency (xerophthalmia): Goblet cell loss, bitot's spots, corneal xerosis; endemic in developing countries; treat with vitamin A supplementation

Systemic Medications Causing DES

Drug Class	Mechanism
Antihistamines	Anticholinergic — reduced lacrimal and goblet cell secretion
Antidepressants (TCAs/SSRIs)	Anticholinergic / altered serotonin — reduced aqueous secretion
Antipsychotics	Anticholinergic — reduced secretion; reduced blink rate
Diuretics	Systemic dehydration reduces tear volume
Beta-blockers (systemic)	Reduced lacrimal gland beta-receptor stimulation
Isotretinoin (Accutane)	Meibomian gland atrophy; goblet cell loss — often irreversible
Oral contraceptives / HRT	Altered androgen/oestrogen balance; meibomian gland effect

TFOS DEWS II Diagnostic Criteria (2017)

Diagnosis requires a positive symptom score PLUS at least one positive homeostasis marker:

Step 1 — Symptoms (required)

• OSDI ≥13 (Ocular Surface Disease Index) — 12-item questionnaire, score 0–100
• DEQ-5 ≥6 (Dry Eye Questionnaire-5) — 5-item quick screen

Step 2 — Homeostasis Markers (≥1 positive required)

• TBUT <10s (fluorescein) or NIBUT <10s (non-invasive)
• Osmolarity ≥308 mOsm/L in either eye, OR inter-eye difference >8 mOsm/L
• Corneal staining ≥2 (Oxford scale) or conjunctival lissamine green staining ≥1 (van Bijsterveld)
• Schirmer I ≤10mm/5min (without anaesthesia)

Additional Diagnostic Tests

Meibography (LipiView / Keratograph 5M): Infrared imaging of meibomian gland structure; Meiboscore 0–3 per lid (gland dropout); essential for MGD subtyping
MMP-9 (InflammaDry): Point-of-care lateral flow assay; ≥40 ng/mL positive; indicates active ocular surface inflammation; guides anti-inflammatory treatment initiation
Corneal topography: Irregular mire patterns from tear film instability; corneal irregularity index; differentiates DES from early keratoconus
Anterior segment OCT: Tear meniscus height and volume quantification (<0.2mm abnormal); corneal epithelial thickness mapping
Confocal microscopy: Corneal nerve density, sub-basal nerve plexus assessment; goblet cell density; research and specialist settings
Conjunctival impression cytology: Goblet cell density; Nelson grading 0–3; gold standard for mucin deficiency assessment

Systemic Investigations (when SS suspected)

Anti-SSA/Ro and Anti-SSB/La antibodies: Sjögren's syndrome serology; positive in 50–70% of primary SS
ANA (antinuclear antibody): Screening test; positive in many connective tissue diseases
RF (rheumatoid factor), anti-CCP: RA screen in secondary SS
Minor salivary gland biopsy: Gold standard for SS diagnosis; focal lymphocytic sialadenitis (focus score ≥1)
Schirmer test with anaesthesia <5mm/5min: Strongly indicative of SS-related ADDE

Management follows the TFOS DEWS II stepwise approach, escalating treatment based on severity and response. Address the underlying mechanism (MGD vs ADDE) alongside symptomatic relief.

Step 1 — Mild DES (All Patients)

Patient education: Condition chronicity, compliance importance, environmental triggers; screen hygiene (20-20-20 rule: every 20 min, look 20 feet away for 20 seconds)
Preservative-free artificial tear substitutes: Sodium hyaluronate 0.1–0.4% (Hylotears, Clinitas), carboxymethylcellulose 0.5–1%, polyethylene glycol (Systane); instil 4–6× daily; avoid preserved drops if using >4× daily (BAK toxicity)
Lid hygiene: Warm compresses (Bruder mask or Eyebag) 10–15 minutes twice daily to liquefy inspissated meibomian secretions; followed by lid massage and lid wipes (HypoChlor, Blephaclean)
Dietary omega-3 supplementation: EPA/DHA 1–3g/day; evidence for improvement in meibomian gland function and tear quality; oily fish diet alternatively
Environmental modification: Increase indoor humidity (humidifier); reduce direct air conditioning/fan exposure; protective wrap-around spectacles outdoors
Review and modify systemic medications: Switch to less anticholinergic alternatives where clinically appropriate; liaise with prescribing physician

Step 2 — Moderate DES

Topical anti-inflammatory therapy:
- – Ciclosporin A 0.05% (Restasis) / 0.1% (Ikervis): Calcineurin inhibitor; reduces T-cell-mediated lacrimal gland inflammation; onset 3–6 months; use BD; approved for chronic DES
- – Lifitegrast 5% (Xiidra): LFA-1 integrin antagonist; reduces lymphocyte recruitment; onset 6–12 weeks; use BD
Punctal occlusion: Collagen (temporary, 1–2 weeks) then silicone plugs (semi-permanent); lower puncta first; reduces tear drainage; contraindicated in active ocular surface inflammation (traps inflammatory mediators)
Intense Pulsed Light (IPL) therapy: Pulsed light 500–1200 nm applied to lower eyelid and malar region; reduces lid margin telangiectasia and meibomian gland inflammation; followed by meibomian gland expression; 4 sessions monthly; evidence-based for MGD-associated DES
Lipiflow Thermal Pulsation: Vectored thermal pulsation device; simultaneous eyelid warming and pulsatile pressure; unblocks meibomian glands; single treatment; effect lasts 6–12 months
Overnight lubricating ointments: Lacri-Lube, Simple Eye Ointment; preservative-free; for nocturnal exposure or severe evaporation
Moisture chamber spectacles / humidity goggles: Reduce environmental evaporation; particularly useful in occupational DES

Step 3 — Severe DES

Oral tetracyclines: Doxycycline 50–100mg OD or 20mg BD (sub-antimicrobial dose); anti-inflammatory via MMP-9 inhibition; improves meibomian gland secretion; effective for rosacea-associated MGD; 3-month courses; avoid in pregnancy/children
Autologous serum eye drops (ASED): 20–100% concentration; contains natural growth factors (EGF, TGF-β), vitamins, immunoglobulins; promotes epithelial healing; key treatment for GvHD, neurotrophic keratopathy, severe SS-DED; requires NHS consultant prescription and refrigeration
Short-term topical corticosteroids: Fluorometholone 0.1% or loteprednol 0.5% QID for 2–4 weeks; rapidly reduces acute inflammation; monitor IOP; not for long-term use due to cataract and glaucoma risk
Scleral contact lenses (large diameter 16–24mm): Vault over cornea, maintain constant fluid reservoir; highly effective for severe DES, GvHD, neurotrophic keratopathy, irregular cornea

Step 4 — Very Severe / Refractory DES

Systemic immunosuppressants: Hydroxychloroquine, mycophenolate mofetil, methotrexate — for SS and GvHD-associated; rheumatology co-management required
Amniotic membrane transplantation (ProKera / PROKERA Slim): Self-retained ring; cryopreserved amniotic membrane promotes epithelial healing, reduces inflammation; for persistent epithelial defects
Permanent punctal occlusion: Thermal or laser cauterisation of puncta; irreversible; only after successful temporary occlusion trial
Tarsorrhaphy: Partial/complete eyelid closure; reduces ocular surface exposure; used in neurotrophic keratopathy, lagophthalmos, corneal perforation risk
Surgical management of lid abnormalities: Ectropion repair, ptosis repair to correct exposure; botulinum toxin to reduce lagophthalmos

Dry Eye Syndrome is a chronic, relapsing-remitting condition for the majority of patients. Complete cure is rarely achievable; the goal is effective long-term symptom control and prevention of ocular surface complications.

Favourable Prognostic Factors

Early diagnosis and initiation of stepwise treatment
Identification and treatment of the underlying aetiology (MGD vs ADDE)
High patient compliance with lid hygiene and artificial tear use
Modification of environmental and behavioural risk factors
Mild-to-moderate evaporative DES (MGD) — excellent response to lid hygiene, IPL, and ciclosporin

Unfavourable Prognostic Factors

Sjögren syndrome-associated DED — more severe, progressive, difficult to treat
Graft-versus-host disease — aggressive cicatrising ocular surface disease
Established corneal scarring, vascularisation, or neurotrophic keratopathy
Significant meibomian gland dropout on meibography (irreversible gland loss)
Non-compliance with treatment regimen
Continued use of causative systemic medications (unable to modify)

Follow-Up Schedule

Mild DES: 3–6 monthly review; monitor TBUT, staining, Schirmer
Moderate DES on anti-inflammatory therapy: 6–8 weekly initially (monitor response to ciclosporin/lifitegrast); then 3–4 monthly
Severe / SS-associated DES: 1–3 monthly; co-manage with ophthalmology and rheumatology
Post-IPL / Lipiflow: 4–6 weeks post-procedure review; repeat as needed every 6–12 months

Many conditions mimic or co-exist with DES. Careful history, slit lamp examination, and targeted investigations help distinguish these entities.

Allergic Conjunctivitis (Seasonal/Perennial/Vernal)

Prominent itching (pathognomonic), chemosis, papillary response; seasonal pattern; +ve allergy history; elevated IgE; eosinophilia in scraping. DES has burning not itching.

Blepharitis (Anterior / Posterior MGD)

Often co-existing with DES. Anterior: Staphylococcal scales at lash bases, collarettes. Posterior: MGD is the most common cause of evaporative DES — not a separate condition but primary aetiology.

Superior Limbic Keratoconjunctivitis (SLK)

Rose Bengal staining of superior bulbar conjunctiva and superior cornea; filamentary keratitis; associated with thyroid disease; redundant superior conjunctiva; responds to topical silver nitrate or thermocautery.

Neurotrophic Keratopathy

Absent or markedly reduced corneal sensation (esthesiometry); persistent epithelial defect with rolled edges; Mackie grade I–III; caused by CN V lesion, HSV, VZV, diabetes, post-surgical; requires neurotrophic treatment (cenegermin — Oxervate).

Mucous Membrane Pemphigoid (MMP) / Ocular Cicatricial Pemphigoid

Progressive cicatrising conjunctivitis; subepithelial fibrosis; forniceal foreshortening and obliteration; symblepharon; severe DES secondary. Confirmed by conjunctival biopsy (IgG/IgA linear basement membrane deposition).

Viral Conjunctivitis (Adenoviral)

Acute onset; follicular response; lymphadenopathy; watery discharge; epidemic keratoconjunctivitis (EKC) causes subepithelial infiltrates; self-limiting 2–3 weeks; may leave pseudo-membranes and secondary DES.

Lagophthalmos / Exposure Keratopathy

Inferior interpalpebral staining in band distribution; nocturnal lagophthalmos common (ask about morning symptoms); CN VII palsy; thyroid proptosis; assess lid closure on slit lamp.

Graft-versus-Host Disease (GvHD)

Post-haematopoietic stem cell transplant; severe bilateral DES with progressive cicatrising conjunctivitis; ciclosporin and scleral lenses; multidisciplinary management with haematology.

Recurrent Corneal Erosion Syndrome

Sudden onset severe pain on awakening; prior corneal trauma or corneal dystrophy (EBMD/map-dot-fingerprint); focal epithelial loosening; not associated with tear film deficiency per se, though DES can co-exist.

Toxic Keratoconjunctivitis

Inferior punctate staining in preserved drop distribution; worsens with increased drop frequency; history of topical medication overuse; improves with switch to preservative-free formulations.

80–90% of DES is evaporative — always examine meibomian glands first

Assess gland expressibility, lid margin telangiectasia, and meibography. Treating MGD is foundational before escalating to systemic therapy. Most patients presenting with "dry eyes" primarily have MGD, not aqueous deficiency.

Paradoxical epiphora is a sign of dry eye, not adequate tears

Reflex hypersecretion from lacrimal glands is triggered by ocular surface irritation from desiccation. Patients who "can't have dry eyes because they cry a lot" may have the most severe DES. Always measure TBUT in tearful patients.

OSDI ≥13 + any positive homeostasis marker confirms DES per TFOS DEWS II

Do not rely on Schirmer test alone — it has poor sensitivity and specificity. Combine symptom questionnaire with objective homeostasis markers (osmolarity, TBUT, vital staining) for robust diagnosis.

Treat the mechanism, not just the symptoms

Aqueous-deficient DES (especially SS) requires anti-inflammatory therapy (ciclosporin/lifitegrast). Evaporative MGD-driven DES responds to lid hygiene, warm compresses, IPL, and doxycycline. Misidentifying the subtype leads to treatment failure.

Contact lens wearers with DES: trial daily disposables before abandoning lenses

Switch to daily disposable silicone hydrogel lenses with lower modulus; consider artificial tear instillation before lens insertion and at end of day; reduce wearing time; scleral lenses as last resort before ceasing lens wear.

Screen for Sjögren syndrome in unexplained severe bilateral DES

Especially in women >40 with sicca symptoms (dry eyes + dry mouth), arthralgia, or fatigue. Request anti-SSA/Ro and anti-SSB/La antibodies. Early diagnosis enables systemic disease monitoring and prevention of systemic complications.

Anti-inflammatory therapy should precede punctal occlusion

Inserting punctal plugs in actively inflamed eyes traps inflammatory cytokines and can worsen DES. Initiate ciclosporin or lifitegrast first, confirm reduced inflammation (negative MMP-9), then consider occlusion.

Pre-operative DES management is critical before cataract or refractive surgery

Untreated DES causes irregular tear film, inaccurate keratometry and biometry, and poor post-operative outcomes. Optimise DES for minimum 4–6 weeks pre-operatively. Repeat biometry after tear film stabilisation.

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Clinical Illustration

Overview

Etiology