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How to Assess and Manage Patients' Tear Film Quantity

TearFilmQuantity.jpg

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

Low: ≤0.1mm or a difference of at least 0.06mm between the eyes
Medium: 0.1mm to 0.25mm
High: ≤0.25mm (indicates reflex tearing and/or deficiency in naso-lacrimal drainage)

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

Reference

Adapted from a handbook of Contact Lens Management (3rd Edition)