How to Assess and Manage Patients' Tear Film Quantity

What you need to know

Slit Lamp Viewing

1. Narrow slit beam with low intensity to measure (with eye-piece graticule) or grade inferior tear meniscus height in primary gaze and with normal blinking.
2. High magnification (40x)
3. Direct focal illumination

Grading

Tear meniscus height

Incidence

Questionnaires - such as:

• Standardized Patient Evaluation of Eye Dryness Questionnaire (SPEED)
• Ocular Surface Disease Index (OSDI)
• Contact Lens Dry Eye Questionnaire (CLDEQ)
• CLDEQ-8, McMonnies Dry Eye Index
• Dry Eye Questionnaire (DEQ)
• Non-invasive tests - tear meniscus height (lower lid margin to top of specular reflex) and regularity
• Invasive tests - Schirmer, Phenol red thread. Invasive and non-invasive break-up time, lipid layer presence.

Etiology

• Multifactorial, including age, medication, systemic or ocular conditions, environment
• Contact lens wear interferes with normal tear film structure and function
• Increased tear film evaporation leads to thinning of pre- and post-lens tear layers

Symptoms

• Dryness, discomfort, grittiness, irritation, sensitivity to adverse environments.

Signs

• Reduced tear meniscus height, irregular tear meniscus (notching or scalloped edge), concave tear profile
• Low Schirmer test scores (at 5 mins, normal >10mm, borderline 5-10mm, severe dry <5mm) or low Phenol red thread test scores (at 15 secs, dry eye <10mm)

Patient Recommendations

Recommendations

• Address associated systemic or ocular conditions
• Artificial tear supplements
• Change lens type (RGP to silicone hydrogel), material or wearing schedule (monthly replacement to two weekly)
• Maintain good lens cleaning including rub and rinse step
• Manage all grades if signs or symptoms exist - improve tear film quality
• Change lens care solution to latest generation of products
• Manage any tear quality issues
• Rewetting drops or liposomal sprays
• Attention to nutrition or nutritional supplements (essential fatty acids)
• Tear retention measures (to reduce drainage and increase tear contact time) such as punctal plugs or surgery
• Manage any meibomian gland issues

Prognosis

Generally good resolution of symptoms with appropriate management unless intractable underlying systemic or ocular condition