Dry Eye Workup
Evidence-based clinical pathway for comprehensive dry eye assessment and management in Singapore, developed in accordance with TFOS DEWS III (2025) guidelines.
Last updated: March 2026
Dry Eye Disease Clinical Workflow
Dry eye disease (DED) is a multifactorial disease of the ocular surface characterized by loss of homeostasis of the tear film, accompanied by ocular symptoms, with tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities playing etiological roles (TFOS DEWS II, 2017).
This workflow is aligned with TFOS DEWS III (2025) — the current international standard — which builds on the DEWS II (2017) framework. It is adapted for optometric practice in Singapore with consideration for local climate, demographics, and available resources.
Structured Intake & Patient History
1.1 Symptom Assessment
Utilize validated questionnaires for standardized symptom assessment:
- OSDI (Ocular Surface Disease Index): 12-item questionnaire scoring 0–100. Grade 0 — Healthy (0–12) · Grade 1 — Mild (13–22) · Grade 2 — Moderate (23–32) · Grade 3 — Severe (33–42) · Grade 4 — Very Severe (≥43). Formula: (sum × 25) ÷ number of items answered.
- DEQ-5 (Dry Eye Questionnaire-5): Rapid 5-item screen scoring 0–22. Grade 0 (<6) · Grade 1 (6–9) · Grade 2 (10–13) · Grade 3 (14–16) · Grade 4 (≥17). DEQ-5 ≥12 — consider Sjögren’s syndrome screening (SS-A/SS-B antibodies) regardless of grade.
- SPEED (Standard Patient Evaluation of Eye Dryness): 8-item assessment of frequency and severity. Useful for rapid chair-side screening.
1.2 Risk Factor Identification
| Category | Risk Factors |
|---|---|
| Environmental | Air conditioning, low humidity, wind exposure, screen time >6 hours/day, Singapore’s tropical climate with indoor air conditioning |
| Systemic | Sjögren’s syndrome, diabetes mellitus, thyroid disorders, rheumatoid arthritis, rosacea, hormonal changes (menopause) |
| Medications | Antihistamines, antidepressants, isotretinoin, beta-blockers, diuretics, oral contraceptives |
| Ocular | Contact lens wear, refractive surgery (LASIK/PRK), incomplete blink, blepharitis, meibomian gland dysfunction |
| Demographic | Age >50 years, female gender, Asian ethnicity (higher MGD prevalence) |
1.3 Singapore-Specific Risk Factors
MGD-dominant evaporative DED accounts for approximately 70% of DED cases in Singapore. The following factors are particularly prevalent in the local context:
Tropical Climate & Environmental Factors
| Environmental Factor | Impact on Dry Eye | Clinical Implication |
|---|---|---|
| High ambient humidity (70–90% RH) | Partially protective outdoors | Symptoms may fluctuate; assess in clinical context |
| Pervasive air-conditioning (22–24°C) | Marked indoor humidity reduction | Indoor environment is the major trigger in SG |
| High UV index (UVI 10–14 daily) | Ocular surface inflammation | Photoprotective lenses recommended |
| Urban particulate matter (PM2.5) | Conjunctival irritation | Peak PSI periods may worsen grade |
| Contact lens wear (>40% urban SG) | Reduced TBUT; lipid disruption | Assess CL wear hours; switch modality PRN |
| Screen time (avg >9 hr/day SG) | Reduced blink rate (~50%) | Blink training; 20-20-20 rule counselling |
Ethnic & Demographic Considerations
| Population Group | Considerations | Relevant Adjustment |
|---|---|---|
| Chinese (74%) | Higher myopia → more CL wearers; LASIK-associated DED common | Post-refractive DED protocol; Grade 1–2 common |
| Malay (13%) | Higher MGD prevalence; cosmetic eye practices | Lid hygiene emphasis; MGD Grade 2–3 |
| Indian (9%) | Higher Sjögren’s susceptibility; systemic autoimmune overlap | Lower threshold for ANA/RF screening; Grade 3–4 |
| Elderly (>65 yr) | Androgen decline → gland atrophy; polypharmacy | Medication review; Grade 2–3 common |
| Paediatric (screen-related) | Rising prevalence; atypical presentation | DEQ-5 adapted; typically Grade 1–2 |
1.4 Medical & Medication History
- Document all systemic medications and supplements
- Screen for autoimmune conditions (especially Sjögren’s syndrome)
- Previous ocular surgeries or procedures
- Contact lens history (type, wearing schedule, solution use)
- Current topical medications and preservative exposure
Clinical Examination Protocol
2.1 Examination Sequence (Least to Most Invasive)
Symptom Questionnaire
OSDI, DEQ-5, or SPEED before any examination
Non-Invasive Tear Break-Up Time (NIBUT)
Preferred over fluorescein TBUT — avoids reflex tearing. Mean NIBUT (Keratograph): ≥7.8 s = Grade 0 (Healthy) · 5–7 s = Grade 1 · 3–4 s = Grade 2 · <3 s = Grade 3–4. First NIBUT <11 s indicates an unstable tear film.
Tear Meniscus Height (TMH)
Anterior OCT or slit lamp. Grade 0 ≥0.25 mm · Grade 1: 0.20–0.24 mm · Grade 2: 0.15–0.19 mm · Grade 3: 0.10–0.14 mm · Grade 4: <0.10 mm.
Lid & Meibomian Gland Assessment
Lid margin evaluation, gland expressibility, secretion quality
Blink Assessment
Frequency (normal: 12–15/min) and completeness during conversation and reading
Tear Film Break-Up Time (TBUT) with Fluorescein
Instil PF fluorescein; ask patient to blink once; measure time to first break under cobalt-blue illumination. Repeat ×3; record mean. Grade 0 ≥10 s · Grade 1: 5–9 s · Grade 2: 3–4 s · Grade 3: 1–2 s · Grade 4: <1 s.
Ocular Surface Staining (Fluorescein + Lissamine Green)
Allow 2–3 minutes after fluorescein instillation before grading under cobalt-blue illumination. Oxford scale: Grade 0 (0 dots) · Grade I (1–5 dots) · Grade II (6–30 dots) · Grade III (≥31 dots) · Grade III + filaments (Very Severe). Lissamine green for conjunctival assessment (van Bijsterveld grading).
Schirmer I Test (if indicated)
Without anaesthesia (reflex + basal secretion). Grade 0 ≥10 mm · Grade 1: 6–9 mm · Grade 2: 3–5 mm · Grade 3: 1–2 mm · Grade 4: ≤1 mm. Note: ~25% sensitivity — a positive result is clinically significant. Consider phenol-red thread test as alternative.
2.2 Meibomian Gland Dysfunction (MGD) Assessment
MGD is present in 85% of evaporative dry eye cases. Systematic evaluation is essential:
| Parameter | Assessment Method | Grading |
|---|---|---|
| Lid Margin | Slit lamp evaluation | Normal, irregular/thickened, vascular engorgement, plugging/pouting, displacement |
| Gland Expressibility | Firm pressure on 5 central lower lid glands | Grade 0: All glands expressible Grade 1: 3–4 glands expressible Grade 2: 1–2 glands expressible Grade 3: No glands expressible |
| Secretion Quality | Observe expressed meibum | Grade 0: Clear fluid Grade 1: Cloudy fluid Grade 2: Granular / turbid Grade 3: Inspissated / no expression (→ DED Grade 4) |
| Gland Dropout | Meibography (if available) | Grade 0: 0–25% loss Grade 1: 26–50% loss Grade 2: 51–75% loss Grade 3: >75% loss (→ DED Grade 3–4) |
Classification & Severity Grading
3.1 TFOS DEWS III Classification (2025)
DEWS III (2025) retains the ADDE/EDE framework from DEWS II and formally adds a third primary driver subtype: Pain-Dominant DED. Up to 30–40% of patients carry a mixed subtype.
Aqueous Deficient Dry Eye (ADDE)
Primary Mechanism: Reduced tear production
Key Findings:
- Reduced tear meniscus height (<0.25 mm — Grade 1+; <0.10 mm Grade 4)
- Low Schirmer I (<10 mm/5 min — Grade 1+; <3 mm Grade 3+)
- May have normal TBUT initially
- Associated with Sjögren’s syndrome or lacrimal gland dysfunction
Evaporative Dry Eye (EDE)
Primary Mechanism: Excessive tear evaporation
Key Findings:
- Normal or near-normal tear volume
- Reduced TBUT (<10 seconds)
- MGD present in 85% of cases
- Most common type in Asian populations
Pain-Dominant DED (DEWS III, 2025)
Primary Mechanism: Central sensitisation / neuropathic ocular pain
Key Findings:
- Burning, hyperalgesia, or allodynia disproportionate to clinical signs
- OSDI/SPEED scores markedly elevated despite minimal staining or normal TBUT
- Poor response to conventional lubricants and anti-inflammatories
- Screen using pain-specific questions; refer to ophthalmology or pain specialist if suspected
Note: Mixed subtypes (ADDE + EDE, or either combined with Pain-Dominant) are common. Treatment-refractory patients should be screened for a pain-dominant component before escalating ocular surface therapy.
3.2 Severity Grading System
Overall DED grade = most severe single finding across all parameters. Grade 0 indicates a healthy ocular surface with no DED detected. Use the Dry Eye Severity Grader tool for interactive, instant grading at the chair side, or download the printable PDF worksheet for slit-lamp use.
| Grade | OSDI / DEQ-5 | TBUT (Fluorescein) | NIBUT (Mean) | Oxford Staining | Schirmer I | TMH |
|---|---|---|---|---|---|---|
| Grade 0 — Healthy | OSDI 0–12 / DEQ-5 <6 | ≥10 s | ≥7.8 s | Oxford 0 (0 dots) | ≥10 mm | ≥0.25 mm |
| Grade 1 — Mild | OSDI 13–22 / DEQ-5 6–9 | 5–9 s | 5–7 s | Oxford I (1–5 dots) | 6–9 mm | 0.20–0.24 mm |
| Grade 2 — Moderate | OSDI 23–32 / DEQ-5 10–13 | 3–4 s | 3–4 s | Oxford II (6–30 dots) | 3–5 mm | 0.15–0.19 mm |
| Grade 3 — Severe | OSDI 33–42 / DEQ-5 14–16 | 1–2 s | <3 s | Oxford III (≥31 dots) | 1–2 mm | 0.10–0.14 mm |
| Grade 4 — Very Severe | OSDI ≥43 / DEQ-5 ≥17 | <1 s | <3 s (Gr 3 max) | Oxford III + filaments | ≤1 mm | <0.10 mm |
MGD domain grade = most severe finding across: meibum quality · gland expressibility · meibography dropout · lid margin thickening · lid margin vascularity. MGD Grade 3 (inspissated / none expressible / >75% dropout) elevates overall DED to Grade 4.
Evidence-Based Treatment Ladder
Level 1: Mild Dry Eye
Patient Education & Lifestyle Modifications
- Explain dry eye pathophysiology and chronic nature
- Environmental modification: humidifiers, reduce air conditioning exposure, position away from direct airflow
- Digital device usage: 20-20-20 rule (every 20 min, look 20 feet away for 20 sec)
- Conscious blinking exercises, especially during screen use
- Adequate hydration (8 glasses water/day), omega-3 rich diet
- Protective eyewear outdoors (wrap-around sunglasses)
Artificial Tears
- Preservative-free formulations preferred if using >4 times/day
- Start with low-viscosity drops for daytime use
- Gel or ointment for nighttime if needed
- Frequency: Minimum 4 times/day, increase as needed
Lid Hygiene (if MGD present)
- Warm compresses: 40–45°C for 5–10 minutes, twice daily
- Lid massage: Gentle downward strokes on upper lid, upward on lower lid
- Lid scrubs: Diluted baby shampoo or commercial lid wipes, once daily
Level 2: Moderate Dry Eye
Continue all Level 1 treatments and add:
Omega-3 Fatty Acid Supplementation
- Dosage: EPA + DHA ≥2000 mg/day (EPA:DHA ratio 3:1 to 4:1 preferred)
- Duration: Minimum 3–6 months for therapeutic effect
- Evidence: Meta-analyses show improvement in TBUT, OSDI scores, and tear osmolarity
- Particularly effective for MGD-related evaporative dry eye
Anti-Inflammatory Therapy
🏥 SINGAPORE PRACTICE NOTE
Anti-inflammatory medications require prescription. Refer to ophthalmologist or collaborate with general practitioner for medication management.
- Cyclosporine A 0.05%: Twice daily. Onset 3–6 months. Reduces inflammation, increases tear production
- Lifitegrast 5% (Xiidra): Twice daily. Faster onset (2 weeks). LFA-1 antagonist. Note: Not registered with HSA Singapore — currently available in the US only. Cyclosporine A 0.05% is the locally available anti-inflammatory option.
- Short-term topical corticosteroids (e.g., fluorometholone 0.1% QID for 2 weeks) for acute exacerbations
Tear Conservation
🏥 SINGAPORE PRACTICE NOTE
Punctal plug procedures are performed by ophthalmologists in Singapore. Refer appropriate candidates.
- Punctal plugs: For aqueous deficient dry eye unresponsive to lubricants
- Trial with temporary collagen plugs (dissolve in 7–10 days) before permanent silicone plugs
- Insert lower puncta first; add upper if needed
- Monitor for epiphora, increased discharge, or granuloma formation
Level 3: Severe Dry Eye
Continue all previous treatments. Most Level 3 interventions require ophthalmology referral in Singapore:
Advanced MGD Therapy
🏥 SINGAPORE PRACTICE NOTE
Advanced MGD procedures (thermal pulsation, IPL, meibomian gland probing) are performed by ophthalmologists. Refer candidates with severe MGD unresponsive to conservative therapy.
- Thermal Pulsation (LipiFlow): Automated heating + pulsatile pressure. Single 12-minute treatment. Improvement lasts 6–12 months
- Intense Pulsed Light (IPL): 3–4 sessions at 2–4 week intervals. Reduces lid inflammation, improves meibum quality
- Meibomian gland probing: For obstructed glands unresponsive to conservative therapy
Autologous Serum Tears
🏥 SINGAPORE PRACTICE NOTE
Autologous serum preparation requires medical oversight and laboratory facilities. Refer to ophthalmology.
- 20–50% concentration in preservative-free saline
- Contains growth factors, vitamins, immunoglobulins, fibronectin
- Particularly effective for severe aqueous deficiency and neurotrophic keratopathy
- Requires proper storage (refrigeration) and patient compliance
Systemic Therapy
🏥 SINGAPORE PRACTICE NOTE
Systemic antibiotics require prescription. Collaborate with ophthalmologist or general practitioner for medication management.
- Oral tetracyclines: Doxycycline 50–100 mg daily or azithromycin 500 mg daily for 3 days, then 250–500 mg 3×/week
- Anti-inflammatory and lipid-altering properties beneficial for MGD and rosacea-associated dry eye
- Duration: 3–6 months minimum
Bandage Contact Lenses
✓ OPTOMETRIC SCOPE
Bandage contact lens fitting is within optometric scope in Singapore. Close monitoring essential.
- Silicone hydrogel lenses for persistent epithelial defects
- Scleral lenses create fluid reservoir, protect ocular surface
- Requires careful monitoring for infection risk
- Consider co-management with ophthalmology for complex cases
Level 4: Refractory / Very Severe Dry Eye
Referral to Ophthalmology
Refer for consideration of:
- Surgical intervention: Permanent punctal occlusion, tarsorrhaphy, salivary gland transplantation
- Immunosuppressive therapy: For severe autoimmune-related dry eye (Sjögren’s syndrome)
- Amniotic membrane transplantation: For persistent epithelial defects or severe limbal stem cell deficiency
- Investigation of systemic causes: Rheumatology referral if autoimmune disease suspected
⚠️ Red Flags Requiring Urgent Referral:
- Corneal infiltrate or suspected microbial keratitis
- Persistent epithelial defect >2 weeks despite treatment
- Corneal ulceration or thinning
- Significant visual impairment affecting daily activities
- Suspected Stevens-Johnson syndrome or other severe ocular surface disease
Follow-Up & Monitoring Protocol
| Severity Level | Initial Follow-Up | Subsequent Monitoring | Key Parameters |
|---|---|---|---|
| Mild | 4–6 weeks | 3–6 months if stable | OSDI score, TBUT, symptom improvement |
| Moderate | 2–4 weeks | 1–3 months | All baseline tests, medication tolerance, MGD improvement |
| Severe | 1–2 weeks | 2–4 weeks initially, then monthly | Comprehensive examination, staining scores, medication compliance |
| Very Severe | 3–7 days | Weekly until stabilized | Full workup, corneal integrity, vision assessment, coordinate with ophthalmology |
Treatment Response Assessment
Criteria for Adequate Treatment Response:
- ✓≥20% improvement in OSDI or symptom score
- ✓Improvement in TBUT (≥2 seconds increase)
- ✓Reduction in ocular surface staining (≥1 grade improvement)
- ✓Patient-reported improvement in quality of life
If inadequate response after 4–6 weeks: Re-evaluate diagnosis, assess compliance, escalate treatment tier, or consider referral.
Special Considerations for Singapore Practice
Contact Lens-Related Dry Eye
- Highly prevalent: 50% of contact lens wearers experience symptoms
- Management approach:
- Reduce wearing time, consider daily disposables
- Switch to high-water-content or silicone hydrogel materials
- Preservative-free rewetting drops during wear
- If severe: Contact lens holiday (1–2 weeks) with aggressive dry eye therapy
- Consider discontinuation if refractory despite optimal management
Post-Refractive Surgery Dry Eye
- LASIK/PRK causes transient neurotrophic dry eye (3–6 months typical duration)
- Pre-operative screening critical: Identify pre-existing dry eye, optimize before surgery
- Post-operative protocol:
- Intensive preservative-free lubrication (hourly initially)
- Consider autologous serum for severe cases
- Punctal plugs if persistent >3 months
- Collaborate with operating surgeon for complex cases
Regulatory & Referral Pathways in Singapore
- Optometrists and Opticians Act: Optometrists can diagnose and co-manage dry eye disease
- Prescription medications: Cyclosporine, lifitegrast require medical prescription. Collaborate with ophthalmologist or general practitioner
- Referral indications:
- Lack of improvement after 3 months optimal therapy
- Suspected systemic disease (rheumatology workup needed)
- Corneal complications (ulceration, thinning, scarring)
- Need for advanced procedures (IPL, thermal pulsation, surgical intervention)
- Documentation: Detailed referral letter with baseline measurements, treatment history, severity grading essential for continuity of care
References
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