Week 3: Lacrimal Drainage

Question 1

What the path for lacrimal flow?

Answer 1

Tears begin by being secreted by the lacrimal gland and Wolfring/Krause glands

The tears pass laterally across the ocular surface travelling nasally.

A portion of tear is lost due to evaporation (depending on size os palpebral aperature (open eye)), blink rate, temperature and humidity.

70% of the remainder is drained throught the lower canaliculi and 30% via the upper due to gravity.

Question 2

How does the blink function drain the tears?

Answer 2

When we blink compression from teh orbiucularis muscle both occludes the punctum (opposing them against each other)

This pushes tears into the nasolacrimal sac

when we open our eyes the nasolacrimal sac empties and new tears are sucked into the canaculi - ready for the cycle to repeat

Question 3

What is the difference between a true epiphora and hypersection?

Answer 3

True Epiphora

• medial location
• may have ectopia puncta or palpable blockage
• tears produced at appropriate rate, but not drained effectively

Hypersecretion

• more likely lateral location
• seconday to irritation
• more common
• tear produced at rate faster than blink process can drain

Question 4

What are the 3 way to treat Aqueous Defiency Dry Eye?

Answer 4

Replace Tears
Preserve Tears
Stimulate Tears

Question 5

Give 3 examples that Replace Tears

Answer 5

○ Preserved are cheaper but over exposure can be bad
○ Non preserved - are more expensive and harder to use
○ They can have different viscosity (e.g. gel)
○ Lipid component - some are designed to also help with the lipid component of tears
○ Autologous - made via blood centrifuge (expensive)
○ Manuka honey drops
§ Increase tear osmolarity
§ Improving tBUT
Can sting some patients

Question 6

Give an example that preserve tears

Answer 6

punctual plugs
○ Can be permanent or dissolvable
○ Can also get surgery to get them permanently closed
Blocks drainage of ocular surface

Question 7

Give 2 Examples that stimulate tears

Answer 7

Secretagogues - drugs that encourage aqueous secretion
○ Diquafosol 3% (Diquas, Santen Pharmaceuticals)
§ (not available in aus)
§ promotes tear fluid and protein secretion by conjunctival epithelium and goblets cells (mucins) via elevation of intracellular calcium ion levels
§ Adverse effect: eye irritation, blepharitis, discharge, conjunctival hyperemia
○ Nasal neurostimulation
§ Irritating the nose to cause tear secretion

Question 8

Name 3 cause of Evaporative Dry Eye

Answer 8

Blepharitis
Meibomian Gland Dysfunction
Blink/eyelid abnormalities

Question 9

Treatments for Meibomian Glands

Answer 9

Heat application
MBG expression
Golf spud lid margin debridement

Question 10

What are the steps for Evaluation of Epiphora?

Answer 10

1. Gross examination of the eye
2. Biomicroscopic examination of the eye
3. Invasive/physical examination

Question 11

What questions do you ask during Gross Examination of the eye?

Answer 11

a. Is there visible epiphora, Are the eyes symmetrical ?
b. Is there sign of ectropion? Does the puncta oppose the globe?
c. Is there any sign of inflammation (swelling, redness) at medial canthus?
d. Does the blink process occur as required? Do the lid margins meet effectively?

Question 12

What questions do you ask during Biomicroscopic examination of the eye?

Answer 12

a. Is the tear meniscus even across the entire lid margin? Is there symmetry between the eyes?
b. Is there sign of obstruction, inflammation, or stenosis or the punctum
c. Are there signs of any irritants such as trichiasis?

Question 13

What do you do during Invasive / physical examination?

Answer 13

Palpate the lacrimal sac

Fluorescein retention test

Probing and irrigation

Jones 1 or 2 test