Eyelids & Lacrimal System

Question 1

3 constituents of tear film
In order from most superficial - deepest

Answer 1

1. Superficial lipid layer - formed by secretions of Moll Glands, Zeiss & Meibomian
2. Intermediate aqueous layer - formed from secretions from the main & accessory lacrimal glands of Krause & Wolfring
3. Innermost mucin layer - formed through conjunctival goblet cells, stratified squamous cells of the cornea and conjunctival epithelium

Question 3

Functions of the tear film x5

Answer 3

• creates a nearly perfectly smooth surface on the cornea surface

• keeps corneas surface and conjunctiva moist

• transfers o2 from air into the cornea

• flushes away harmful irritants

• provides ideal refractive media for light

Question 4

Osmolarity in tears

Answer 4

Measure of the amount of milliosmoles / litre of a solution.
Refers to the concentration of dissolved solutions and is important in detecting health of tear film.

Question 5

Dacryocystitis

Answer 5

Infectious inflammation of lacrimal sac, deemed acute or chronic.

• acute dacryocystitis formed by bacterial infections formed from lacrimal drainage apparatus being blocked.
• most commonly seen on new born babies / infants and also common in elderly

Symptoms:
• painful swelling
• watery eyes / mucopurulent discharge

Signs:
• swelling of surface is inflamed, below inner canthus around lacrimal sac
• redness at nasal conjunctiva
• discharge of pus/mucus exiting the lacrimal puncta when pressure applied

Question 6

Dacryoadentitis

Answer 6

Unilateral or bilateral inflammation of lacrimal glands.

Typically idiopathic with no underlying cause

Can be a sign of some underlying pathology

Signs
- painful and red swelling beneath lateral end of upper eyelid

Symptoms
- painful swelling in lacrimal gland region on supero-temporal part of orbit.
- epiphoria (watery eyes) and discharge
- redness of the overlying skin