4. Dry eye disease Flashcards
(13 cards)
What are the two types of Dry eye disease?
ADDE - aqueous deficient dry eyes- this is associated with sjogren’s disease.
EDE - Evaporative dry eyes - 80% of Pxs have this type.
Some Pxs can have a combination of both.
What is the cycle of Dry eye disease?
- Tear film instability
- Excessive evaporation from ocular surface
- Increased osmolarity of the tear film
- Damage to surface cells (mostly goblet)
- Inflammation of ocular surface
- Loss of microvilli glycocalyx and goblet cells. (found at base of tears where mucin layer is spreading across epithelium)
This is a cycle so back around.
What can tear film instability be caused by?
Preservatives, Allergy, CL wear
How can excessive evaporation from ocular surface arise?
Due to meibomian gland dysfunction or unstable lipid layer.
What are the risk factors of Dry eye disease?
- Age
- Female
- Asian
- Meibomian gland dysfunction
- Sjogren syndrome
- Computer use
- CL use
- Hormone replacement therapy
- Environment: polluntion, low humidity
- Medication: antihistamines, antidepressants
What are examples of topical treatments that may worsen Dry eye disease?
- Decongestants
- Anti allergics
- Anti virals
- Beta blockers
- Adrenergic agonists
- Cholinergic agonists
- Mydriatics and cycloplegics
- Anaesthetics
- NSAIDs
What is important about the diagnosis of Dry eye disease?
Optom needs to work out where on the circle of doom the Px is and how long they have been there. Need to know the major cause behind the dry eye disease before crafting treatment plan because it could be an environmental cause that can easily be stopped by talking to the Px rather than needing any sort of medical intervention.
What is the definition of DED?
Dry eye is a multifactorial disease of the ocular surface characterised by a loss of homeostasis of the tear film, and accompanied by ocular symptoms .
Describe the lipid layer of the tear film.
Source:
Meibomian glands, glands of Zeiss and Moll’s gland
Components:
*Polar and non polar layer
*Cholesterol
*Phospholipids
Function:
Reduces evaporation
Maintains optically smooth surface
Describe the Aqueous layer of the tear film.
Source:
Lacrimal gland, Krause (palpebral) gland, Wolfring (tarsal) gland, conjunctival epithelium
Components:
*Water
*Growth factors
*Proteins - lactoferrin, lysozymes, IgA
*Soluble mucins
*Salts/electrolytes
Function:
Anti bacterial properties.
Flushes away debris.
Anti-inflammatory
Epithelial hydration and oxygenation
Maintains pH and osmolarity
Describe the mucous layer of the tear film.
Source:
Membrane bound mucins from corneal epithelium.
Gel forming mucins from conjunctival goblet cells
Components:
*Membrane bound and secreted
*Glycoprotein
Function:
Converts hydrophobic epithelium to hydrophilic.
Prevents infection
What is non pharmacological management of DED?
- Px education
- Environmental factors
- Diet advice - balance of Omega 3 and 6
- Modification of systemic and topical medications
- Lid hygiene and warm compress
What is pharmacological management of DED?
Ocular lubricants:
Active ingredients in ocular lubricants:
*Osmotic agents
*Lipids
*Viscosity enhancing agents
*Preservatives
*Aqueous supplementation
*Buffers
*Electrolytes
*Anti oxidants
*Cell protectants
