Dry eyes Flashcards
What is the lacrimal functional component composed of? 1. 2. 3. 4. 5.
- lacrimal glands
- ocular surface
- meibomian glands
- eyelids
- sensory and motor nerves
What are the three layers of the tear film?
Mucous layer
aqueous layer
lipid layer
What do goblet cells produce?
mucin
What is the function of the mucous layer?
a) supplies oxygen and electrolytes to the ocular surface,
b) provides antibacterial defence and wound healing
c) Enhances tear film spreading
d) Traps and removes waste materials
d) Traps and removes waste materials
What layer of the tear film is produced by the lacrimal gland?
a) aqueous layer
b) mucous layer
c) lipid layer
a) aqueous layer
What is the purpose of the aqueous layer?
a) Traps and removes waste materials
b) Hydrate mucous layer, supplies oxygen and electrolytes to the ocular surface, provides antibacterial defence and wound healing
c) Enhances tear film spreading, provides a smooth surface and stabilizes the tear film
b) Hydrate mucous layer, supplies oxygen and electrolytes to the ocular surface, provides antibacterial defence and wound healing
Which layer of the tear film is produced by the meibomian gland?
a) aqueous layer
b) mucous layer
c) lipid layer
c) lipid layer
Purpose of the lipid layer?
a) Traps and removes waste materials
b) Hydrate mucous layer, supplies oxygen and electrolytes to the ocular surface, provides antibacterial defence and wound healing
c) Enhances tear film spreading, provides a smooth surface and stabilizes the tear film
c) Enhances tear film spreading, provides a smooth surface and stabilizes the tear film
Dry eye is a multifactorial ___________ of the ocular surface characterized by a loss of _________ of the tear film, and accompanied by ocular__________, in which tear film instability and __________, ocular surface _________ and damage, and ___________abnormalities play etiological roles.
disease homeostasis symptoms hyperosmolarity inflammation neurosensory
disease homeostasis symptoms hyperosmolarity inflammation neurosensory
What are the two types of dry eyes?
1.
2.
- aqueous-deficient dry eye (ADDE)
2. evaporative dry eye (EDE).
tear hyperosmolarity arising from reduced lacrimal secretion due to excessive drainage or impaired/reduced lacrimal gland tear production
aqueous-deficient dry eye (ADDE)
What causes aqueous-deficient dry eye (ADDE)?
Sjogren’s Syndrome , systemic drugs, reflex block
hyperosmolarity due to excessive evaporation from the exposed tear film surface
evaporative dry eye (EDE).
What causes evaporative dry eye (EDE)?
Meibomian gland dysfunction, vitamin A deficiency, topical preservatives, ocular allergy
List some risk factors of dry eye
Aging •Female •Asian •MGD •Connective tissue diseases •Sjogren’s syndrome Low androgen •Computer use •Environment •Contact lens wear
What kind of drugs can cause dry eye?
NSAID Aspirin*, ibuprofen* (THC)* Morphine* Antihistamines: Antiarrhythmic/Bronchodilating Antidepressants And more... Decongestant Pseudoephedrine, phenylephrine
Antihypertensive Diuretic Antineoplastic Cyclophosphamide*, CNS Depressant Acne Treatment Isotretinoin* Hormone-based Therapy Finasteride*, estrogen/progesterone, medroxyprogesterone Neurotoxin
Symptoms of dry eye
Dry or foreign body sensation Mild itching Burning or stinging “sandy” or “scratchy” feeling Irritation or soreness Blurry vision Contact lens intolerance
Signs of dry eye
Redness
Mucus discharge
Increased blink frequency
Intermittent tearing (increased tearing such as to the wind or reading/computer work results from a reflex tearing that does little to increase comfort)
What are the four screening questions
- Do your eyes feel uncomfortable?
- Do you have watery eyes?
- Does your vision fluctuate, especially in a dry environment?
- Do you use eye drops?
Refer to optometrist if yes to any of the above
When to refer patient to doctor
Pain, photophobia, any disturbances of vision, blunt trauma, chemical exposure, imbedded foreign body, heat exposure (e.g. welder’s arc), eye protrusion, or contact lens wear
signs and symptoms of acute angle-closure glaucoma (e.g. red, painful eye with
increased IOP, blurred vision, headache, vomiting)
History of iritis, scleritis, angle-closure glaucoma
Symptoms secondary to medication or to an undiagnosed condition (e.g.
blepharitis)
Symptoms worsen or persistent (e.g. >5 days)
3 ways to manage DED
Environment methods
Supportive methods
Tear supplements
Diet (e.g. omega-3 fatty acids)
replenishing tear volume, tear stabilization, reduction in tear osmolarity, reduction in friction between eyelids and cornea, preservation of smooth refracting surface
OCULAR LUBRICANTS
Adding ________ may better mimic natural tears
electrolytes
The function of lipids: To replace _________ and prevent tear evaporation
To replace low lipid levels and prevent tear evaporation
What is the role of a buffer in medication?
control pH
Disrupts the lipid layer as a detergent by affecting the surface tension and
Cytotoxic to corneal epithelial cells (disrupts tight junctions), goblet cells
BENZALKONIUM CHLORIDE (BAK)
Role: enhance lubrication
increase tear thickness
increase adhesion to the mucus layer of tears àprolong retention time on the ocular surface
protecting against desiccation; protecting the ocular surface
VISCOSITY
List 2 viscosity agents
- Cellulose derivatives
- Dextran Polymers
- Polyvinyls
- Polyols
- Glyco-amino-glycan
- Ointment
- Carbomer resins
List 2 viscosity agents
- Cellulose derivatives
- Dextran Polymers
- Polyvinyls
- Polyols
- Glyco-amino-glycan
- Ointment
- Carbomer resins
T or F: A diet rich in omega-3 fatty acids may or may not help.
T
Pharmacological therapy
•Short-term topical _____
•Long-term topical ______
•Long-term topical _____
Pharmacological therapy
•Short-term topical corticosteroid
•Long-term topical cyclosporine
•Long-term topical lifitegrast
Dry eye symptoms should improve within ______
3 to 5 days
