TERM 1: Dry eye disease Flashcards
How can you classify dry eye disease?
aqueous deficient dry eye
evaporative dry eye
mixed dry eye
What are the risk factors of dry eye disease?
-age
-women
-asian ethnicity (double risk)
modifiable risk factors: hormonal deficiency or imbalance, computer use, CL wear and certain medications
What is the aetiology of dry eye disease?
-Dry eye is recognized as a disturbance of the Lacrimal Functional Unit (LFU)
-The lacrimal glands, ocular surface and lids
- function of the LFU is to preserve the integrity of the tear film, the transparency of the cornea, and the quality of the image projected onto the retina
Disease or damage to any component of the LFU (including the afferent sensory nerves, the efferent autonomic and motor nerves) can destabilise the tear film and lead to ocular surface disease that expresses itself as dry eye
What is the pathogenesis of dry eye disease?
-Tear film hyperosmolarity causes hyperosmolarity of the ocular surface epithelial cells and stimulates a cascade of inflammatory events
What is sjogren’s syndrome?
What is it associated with?
autoimmune disorder consisting of dry eye (KCS) and dry mouth (xerostomia), which often involves nasal and vaginal mucous membranes also
autoimmune diseases such as rheumatoid arthritis and systemic lupus erythematosus
What is the most common cause of tear deficient dry eye?
What does histology show?
What is the most common cause?
acquired primary lacrimal disease-only lacrimal gland involved
infiltration by inflammatory cells, loss of normal structure, atrophy and fibrosis
age-related changes in lacrimal gland morphology and secretion
What is the most common cause of evaporative dry eye?
Meibomian gland dysfunction
What systemic drugs can cause dry eye disease?
Beta blockers
Antihistamines
HRT
Anti-psychotic medications
Isotretinoin
What surgery is dry eye disease a risk factor for?
-LASIK refractive surgery
LASIK has a neurotrophic effect on the cornea, along with other changes in corneal shape, that affect tear dynamics causing ocular surface desiccation.
What are the symptoms of dry eye disease?
mild: irritation, itching, soreness, burning, or intermittent blurred vision
moderate: increased discomfort and frequency of symptoms, and visual effects may become more consistent
severe: have increasing frequency of symptoms or constant symptoms, and visual symptoms may be disabling
What are the signs of dry eye disease?
Conjunctival injection
Conjunctival staining
Corneal staining
Reduced tear meniscus
Filaments
Reduced tear BUT
Reduced Schirmer score
MGD
What must you include in the history taking for DED?
Dry eye questionnaires
Symptoms and signs
Exacerbations
Duration
Severity
Ocular, medical and medication history
What examinations can you do to diagnose dry eye disease?
Slit lamp
Diagnostic tests: tear meniscus height, TBUT, staining (fluorescein, lissamine green), Schirmer test (Schirmer I with or without anaesthetic), tear osmolarity
What is abnormal TBUT?
What is abnormal for schirmer test?
What is abnormal for tear osmolarity?
less than 10 seconds
less than 5mm in 5 minutes
more than 308mOsm/l
What is the management of dry eye disease?
step 1:
Education regarding the condition
Modify local environment
Nutritional advice (including oral essential fatty acid consumption)
Modification/elimination of systematic and topical medications
Ocular lubricants
Lid hygiene and warm compresses
step 2:
Non-preserved lubricants
Tear conservation e.g. punctal plugs
Non-medicated ointment at night
Topical antibiotics for anterior blepharitis (if present)
Oral antibiotics e.g tetracyclines
Topical immunomodulatory drugs e.g. cyclosporin
step 3:
Management in secondary care
Autologous serum
Surgical punctal occlusion
Amnionic membranes
