DRY EYE DISEASE Flashcards
Dry eye disease
disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability with potential damage to the ocular surface.
Ocular surface
Cornea
Conjucntivitis
Accessory lacrimal glands
Meibomian glands
Specific sebaceous glands of the eyelid margin that produce the outer lipid film of the tear film
Structures affected in dry eye disease
Occular surface
Meibomian glands
Lacrimal gland
Layers of the tear film
Superficial thin lipid layer (0.11um)
Middle thick aquoeus layer (7um)
Innermost hydrophilic mucin layer (0.02-0.05um)
Antimicrobial proteins in healthy tears
Lysozyme
Lactoferrin
Growth factors and antinflammatory components in tears
ECF
IL-1RA
Role of soluble mucin 5AC in tears
For viscosity
Which cells secrete soluble mucin 5AC
Goblet cells
Role of electrolytes in tears
For osmolarity
Components of healthy tears
Complex mixture or proteins, mucin, electrolytes
Features of tears in chronic dry eye
Decreased in proteins
Decreased growth fatcors
Decreased solule mucin 5AC
Altered cytokine balance promoting inflammation
Increased electrolytes
Why is there reduced soluble mucin 5AC in chronic dry eye
Goblet cell loss
Reason for increase in dry eye syndrome among young adults aged 18-34 years
Increased use of soft contact lenses
Frequent smartphone and computer usage
Causes or Aetiology of dry eye disease
Decreased tear production
Sjogren syndrome
Excessive evaporation
Structural abnormalities of eyelid position or Decreased blink function
Cause of decreased tear production
Lacrimal gland dysfunction or destruction
Causes of excessive tear evaporation
Meibomian gland dysfunction or posterior blepharitis
Sjogren syndrome
Chronic autoimmune inflammatory characterised by diminished lacrimal and salivary gland function
How does decreased blink function increase
evaporation of tear film
By increasing the area or the time of tear film exposure
Core mechanism of dry eye disease
Evaporation-induced tear hyperosmolarity
Pathogenic triggering mechanisms for dry eye disease
Environmental factors
Infection
Endogenous stress
Antigens
Genetic factors
Conditions that initiate tear film instability
Vitamin A deficiency
Eye allergies
Preservatives in topical medications
Contact lens
Certain cosmetics
Low humidity
Blowing air
Computer vision syndrome
Clinical types of dry eye disease
Evaporative Dry eye disease (EDE)
Aqueous deficient dry eye disease (ADDE)
Mechanism of ADDE
Damage to lacrimal gland
Reduced tear secretion
Tear hyperosmolarity despite normal tear evaporation rate
These factors lead to expansion of autoreactive helper T cells which infiltrate ocular surface and lacrimal gland
Proinflammatory cytokines
Chemokines
Matrix metalloproteinases
Mechanism of EDE
Dysfunction of meibomian gland
Deficiency of tear film lipid
Excessive evaporation of tear film
Tear hyperosmolarity despite normal lacrimal function
Two types of evaporative dry eye
Intrinsic
Extrinsic
Causes of intrinsic evaporative dry eye
Meibomian oil deficiency
Disorders of lid aperture
Low blink rate
Drugs
Environmental factors that cause extrinsic evaporative dry eye
Humidity
Allergy
Causes of extrinsic evaporative dry eye
Vitamin A deficiency
Topical drug preservatives
Contac lens
Environmental factors
Symptoms of dry eye disease
Redness
Burning
Stinging
Pruritis
Photophobia
A drug that causes intrinsic evaporative dry eye
Isotretinoin
Diagnostic investigations in drye ey
Schirmer test
Tear film break up time
Ocular surface staining
Examination of eyelids margins and meibomian gland orifices
Schirmer score
Measures tear secretion
Types of dry eye disease according to the TFOS DEWS classification
Aqueous deficient
Evaporative/ Tear film instability
Combination
Two main types of aqueous deficiennt dry eye disease
Sjogren syndrome dry eye
Non-sjogren dry eye
What is used to determine taer film break up time
FLuorescein
Types of sjogren syndrome dry eye
Primary
Secondary
Ocular surface staining is done with……
Fluorescein and
Lissamine green
Causes of non-sjogren dry eye
Lacrimal deficiency
Lacrimal gland duct obstruction
Reflex block
Systemic drugs
Non-pharmacological treatment oprions for dry eye
Eyelid hygience
Punctal plugs
Tarsorrhaphy
Amniotic membran transplantation
Keratoplasty
Salivary gland transplantation
Tarsorrhaphy
Joining part or all of the upper and lower eyelids so as to partially or completely close the eye
Punctal plugs
Devices inserted into the tear ducts to prevent tear drainage
Keratoplasty
Corneal transplant is a surgery where a damaged cornea is replaced by a donated corneal tissue
Lipid containing supplements are used in ………
Meibomian gland dysfunction
What is used to treat demodicosis
Tea tree oil
Tear conservation therapies
Punctal occlusion
Moisture chamber spectacles/goggles
Demodicosis
Parasitic infection of the skin caused be Demodex spp.
ALgorithms for managing dry eye
TFOS DEWS II treatment protocol
CEDARS algorithm
ASCRS algorithm
CEDARS meaning
Corneal External Disease and Refractive Society
Categories of dry eye based on the CEDARS algorithm
Aqueous deficiency
Blepharitis or Meibomian Gland dysfunction (Evaporative and Non-evaporative)
Goblet cell dysfunction/ Mucin deficiency
Exposure related Dysfunctional Tear Syndrom (DTS)
Which algorithm is used to manage dry eye based on cause and not severity
CEDARS
ASCRS meaning
American Society of Corneal and Refractive Surgery
Which algorithm is used when correct diagnosis has been made
ASCRS algorithm
Pharmacological treatments in dry eye
Artificial tears
Antiinflammatory agents
Topical corticosteroids
Topical cyclosporine A
Tacrolimus/ Pimecrolimus
Tetracyclines
Macrolides
Omega fatty acids
Mainstay therapy for dry eyes
Artificial eyes
Benefits of artificial eyes
Increases tear film stability
Reduces ocular surface stress
Improves contrast sensitivity
Improves optical quality of the surface
Increases quality of life
Examples of artificial eyes
Acetylcysteine
Carmellose sodium
Hypromellose
Polyvinyl chloride
Brand names for acetylcysteine
Ilube
Frequency of aplication for acetylcysteine
Apply every 6-8 hours
Brand names for carmellose sodium
Aqualube
Why corticosteroids are used for short term in dry eye
Raised intraocular pressure
Cataract
Brand names for hypromellose
Artelac
Cool eyes
Natural tears
Corticosteorids used in dry eye diseases
Betamethasone
Dexamethasone
Fluorometholone
Hydrocortisone
Prednisolone
Frequency of application for betamethasone in dry eye
Apply 6 hourly
Dexamethasone frequency of application in dry eye
Apply 4-6 hourly
Fluorom etholone frequency of application in dry eye
Apply 1 hourly for 24-48 hours
Frequency of application for hydrocortisone in dry eye
Apply 6-12 hourly
Frequency of application for prednisolone in dry eye
Apply 1-2 hourly
MOA of cyclosporine A
Inhibits calcineurin-phosphatase pathway by complexing with cyclophilin
Reduces transcription of T cell activating cytokines eg: IL-2
How does topical cyclosporine A increase tear production
Local release of parasympathetic neurotransmitter
Frequency of application of cyclosporine A
One drop at bedtime
MOA of tetracyclines in dry eye
Anti- inflammatory effect
Reduce the synthesis and activity of MMP Reduce production of IL-1, TNF
Reduce collagenase activity
Reduce B-cell activation.
Meibomian gland dysfunction and rosacea have been successfully treated with…………
Tetracyclines
Tetracyclines used for dry eye
Tetracycline
Doxycycline
Minocycline
Why are topical tetracyclines preferred
GIT adverse reactions
Skin problems
Omega fatty acids
Omega-3
Omega-3
Tacrolimus preparation and dosing
0.03% tacrolimus eyedrops plus/minus olive oil
Apply 12 hourly for 14-90 days
MOA of omega fatty acids
Blocks eicosanoids
Reduces cytokines
This has been successfully used to treat blepharitis and meibomian gland dysfunction
Azithromycin 1%
Benefits of azithromycin in dry eye
Improves meibomian gland function and symptoms
Reduces bacterial colonization of the eyelid margins Normalizes the meibomian gland secretion lipid profile
