Dry eye Flashcards
What are risk factors for DED
- Ocular surgery
- Age >40 years
- Female gender
- Medications
- Systemic diseases (e.g., diabetes, hypertension, rheumatoid arthritis, Sjögren’s syndrome, thyroid disorders, etc.)
- Smoking
- Computer vision syndrome
- Environmental factors (humidity, air currents/drafts, air conditioning)
- Contact lens wear
What is DED associated with (impact)
- lower QOL
- increased anxiety and depression
- decreased visual acuity
- D/C of contact lens
- digital eye strain syndrome
what is the definition of DED
“Dry eye is a multifactorial disease of the ocular surface characterized by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play etiological roles.”
What are the layers of the tear film
lipid layer
aqueous layer
mucin layer
What are the components of the lacrimal functional unit
lacrimal glands - (produce aqueous layer of tear film)
meibomian glands - (produce lipid layer of tear film)
ocular surface (cornea & conjunctiva) - (produce mucous layer of tear film)
sensory & motor nerves
eyelids
What does the aqueous layer do and what happens when it is broken down
provides moisture and nutrients
breakdown - causes inflammation, increases symptoms of dry eye
What does the lipid layer do and what happens when it is broken down
Layer for eyelids to blink over
breakdown - tear film evaporates quickly, irritating to blink
What is the role of the tear film
- nutrition/O2 (cornea does not have blood vessels)
- blink
- support CL wear
- lubrication
- vision
- lid margin (inflammation)
What is the vicious circle of DED
different factors can result in entering circle
inflammatory mediators
Surface damage
tear film instability
tear film hyper-osmolarity
What if a patient is asymptomatic but has signs of ocular surface disease
- can be neurotropic condition
- not sending messages to brain
- more severe
What is evaporative dry eye
- most prevalent form of dry eye
- Defined by a lack of quality tears (usually the lipid component)
- Leads to quick evaporation of tears on the ocular surface
- Most common: meibomian gland dysfunction
What is aqueous deficient dry eye
- Very uncommon to have aqueous deficient dry eye without overlapping signs of evaporative disease (will be mixed)
- Aqueous deficient dry eye is defined by a lack of aqueous tear production by the lacrimal gland
- Common causes: Sjogren’s syndrome, aging, systemic drugs
Staging of DED
- triaging questions
- risk factor analysis
- diagnostic tests
- subtype classification tests
How are symptoms evaluated
Grading (0-5) based on how uncomfortable
What are symptoms of DED
– Foreign body sensation – Sandy/scratchy feeling – Burning – Itching – Tired eyes – Feeling of dryness – Increased tearing – Vision related problems (intermittent blur, particularly later in the day)
Symptoms tend to worsen over the course of the day, except with evaporative dry eye which is worse in the morning
How is evaporative DED graded
grade secretions
- Mild: Good secretions
- Moderate: plugging of the gland, vascularization of the eyelid margins
- Severe: blocked meibomian ducts (thick secretions)
How is aqueous deficiency DED graded
staining with fluorescein dye (glowing = damage to cornea)
grade 0 - normal
grade 3 - worst
Goals of therapy
- Improve patient’s ocular comfort and quality of life
- Return the ocular surface and tear film to the normal homeostatic state
Self care ocular (personal) consideration
- Hot compresses
- Lid hygiene
- Modifications to contact lens wear
Self care non-ocular considerations
- Environmental modification (humidity, air movement, screen use)
- Systemic medications
- Dietary supplements
- Alcohol use
- Smoking
- Hormonal status
- Sleep apnea
What is the main therapy for DED
Tear supplements or lubricants
How often should artificial tears be used
Frequency depends on severity
- intermittent symptoms: use when symptomatic
- chronic - use daily (2-4 times/day)
What are the downfalls of artificial tears
- Do not address the underlying inflammation causing Dry Eye
- Do not contain the complex mixture of proteins, mucins or other factors found in healthy tears
- Provide temporary palliative relief
- Do not restore normal tear composition
- Do not reverse damage to ocular surface
What are the factors/components of artificial tears
- Preservatives
- Electrolyte composition
- Osmolarity
- Viscosity (increase in thickness increases retention time)
What are benefits of artificial tear SOLUTIONS
- newer formulations contain hyaluronate (naturally occurring in eye)
- Adds viscoelasticity: increased tear stability, reduction of tear removal, protective effects on the corneal epithelium
What are benefits of artificial tear GELS AND OINTMENTS
- Ointments typically mineral oil and petrolatum
- Some have lanolin which can be irritating
- Ointments do not support bacterial growth (do not require preservatives)
- Some may use parabens for preservative but not tolerated well
- Gels–less viscous but provide increased retention time
- gels have preservatives
- Disadvantage: blurring
What are benefits of artificial tear LIPID BASED EMULSIONS
have a long residence time on the tear film, reduce the tear evaporation rate and have a positive effect on the lipid layer (great for evaporative DED)
also improve ocular bioavailability of lipophilic or poorly water-soluble drugs
Examples: Systane Balance, Soothe XP, Refresh Optive Advance
Artificial tears with preservatives
- May be toxic to the cornea
- Most ATs are preserved with less toxic and newer agents that dissipate or change to water when enter the eye (but when tear film is affected, inactivation does not occur quickly)
- Not recommended for extremely dry eye patients
Artificial tears without preservatives
- Eliminate the risk of toxic side effects
- Occasionally patient may react to the buffer in the solution
- Come in uni-dose vials and multi-dose (Maybe more difficult to use)
- Much better for severe dry eye
Benefits of warm compresses
- non-invasive and easy
- have poor adherence (difficult to maintain temp)
- ideal temp is 32–45°C (the more obstructed, the higher temp should be)
- should be applied minimum 5 mins once daily
What are the benefits of eyelid hygeine
- removes bacteria, dirt, and debris
- commercially available products
- alcohol based wipes irritating to patients with rosacea
- can use baby shampoo
- do not put into eye (only eyelid margin, skin around eye and eyebrow)
When should a patient expect relief
- in mild cases, improvement within a week
- if no improvement, refer for full assessment
How long should management for DED be continued
- chronic disease
- continue indefinitely
What modifications can be made to environment
- reduce screen time
- avoid dry environments (humidity control)
- protect eyes from wind
Benefits of Omega-3
Supports proper tear function, cognitive and cardiovascular health and brain function.
