wk2: AED - Wet Eye

Question 1

What is the role of the Aqueous layer of the tear film? (2)

Answer 1

Provides the tissue with: moisture, oxygen and nutrients

Also: removes waste, flushing mechanism

Question 2

What is the role of the mucin layer of the tear film? (2)

Answer 2

Allows the aqueous layer to adhere to the epithelial cells of the cornea - by reducing surface tension between these two layers. Therefore acts as a wetting and stabilising agent.
- [increases hydrophilicity of corneal epithelial cells]

Question 3

Name the tear film layers in order from most to least superficial, and state their thickness (3)

Answer 3

Lipid layer - 0.1um
Aqueous layer - 7um
Mucin layer - 0.05um

Question 4

How does the lower eyelid relate to lacrimal drainage?

Answer 4

It holds a tear reservoir

Question 5

How is our tear film replenished?

Answer 5

Replenished with each blink. The meibomian gland produces lipids, then the lids close to meet each other. As the lids open again, the upper lid draws up the lipid into a lipid layer. So a new lipid/oil layer is placed on the tear film with each blink

Question 6

What is the role of the lipid layer of the tear film?

Answer 6

seals the tear film and reduces evaporation (of tears)

Question 7

How do the eyelids interact with tears?

Answer 7

Lid action pushes tears to the drainage sites (lacrimal pump)

Question 8

What is a “lacrimal lake”?

Answer 8

the pool of tears in the lower conjunctival cul-de-sac, which drains into the opening of the tear drainage system (puncta lacrimalia)

Question 9

Describe the steps in how tears drain to the nose

Answer 9

1. Lid+capillary action - draws tears into lacrimal sac through puncta and canaliculi
2. Lacrimal sac - drains via nasolacrimal duct into back of nose
3. Valve of Hasner prevents movement the other way

Question 10

What is the main cause of wet eye?

Answer 10

Reflex tearing (e.g. in response to being poked in the eye, etc. it’s a reflex)

Question 11

Name 5 causes of Wet Eye (note: there are many others)

Answer 11

Reflex tearing
Blocked gland or puncta
Epiphora
Lacrimal sac obstruction
Allergic Rhinitis

(A REBEL is how I’ll remember this)

Question 12

Define Epiphora

Answer 12

tear overflow from the ocular surface

Question 13

Name 3 general factors that contribute to wet eye

Answer 13

tear overproduction
poor tear support/movement across surface
impaired tear drainage

Question 14

List 5 potential symptoms of wet eye that can help us understand its cause

Answer 14

watery eye (uni/bilateral) with fluid leak onto cheek
slight discomfort (usually)
blurred vision
worse in cold/windy conditions
worse in hot/dry conditions

Question 15

Which tears run down your cheek? Basal or Reflex?

Answer 15

Reflex tears. Basal tears stay in your eye

Question 16

Sometimes when you tell a patient they have dry eyes, the patient will exclaim “No, I have wet eyes!”. What is likely going on to make the patient think this?

Answer 16

The tearing in the eyes in these cases are due to reduction in the normal basal tears and subsequent overcompensation of the lacrimal glands, producing reflex tears

Question 17

What is the purpose of basal tears?

Answer 17

They coat the surface of your eyes, forming a “tear layer”, which hellps keep your vision clear

Question 18

Name the 3 types of tears

Answer 18

Basal
Reflex
Emotion (not as much is known about this one. Some studies suggest they contain more toxins then reflex tears so can be good to remove toxins)

Question 19

What might slight discomfort in a patient with wet eye indicate about aetiology?

Answer 19

Could be overproduction/dry eye related

Question 20

What might tears running down the face of a wet eye patient indicate about aetiology?

Answer 20

Could be dry eye related

Question 21

What might wet eye symptoms being worse in cold/windy conditions indicate about aetiology of the wet eye?

Answer 21

Usually means the problem is anatomical or obstructional

Question 22

What might wet eye symptoms being worse in hot/dry conditions indicate about aetiology of the wet eye?

Answer 22

Usually overproduction/dry eye related

Question 23

Name 5 signs of wet eye

Answer 23

Increased marginal tear prism 
Lid anomalies 
Drainage blockage
Dry eye
Stenosed (narrowed) puncta

Question 24

Why do we have 2 puncta?

Answer 24

Our drainage system relies on both gravity and the movement of eye muscle, which causes a wave of contraction and causes the punctum hole to open and draw in debris

Question 25

What questions should you ask/things to consider in history when dealing with a wet eye patient? (11. Try and remember 5)

Answer 25

Age (e.g. infants)?
True tear spillage or just poor vision?
When are symptoms worst; are they acute or chronic?
Associated Discomfort?
Previous therapy for these symptoms?
Previous CNVII related events, tearing while eating?
Medication?
Red eye, discharge, lid crusting, allergies?
Pain or swelling near lacrimal sac (or gland)?
Surface trauma?
Lid or conjunctiva trauma/surgery/scarring?