Dry eye disease Flashcards
what is dry eye disease defined as
Dry eye is a multifactorial 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. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface
why is rose bengal a good indicator of dry eye
because it is a good indicator of severe ocular damage, as it stains dead cells for diagnostic findings
which 2 groups of people have been identified as major risk factors for dry eye
- older age
and - female gender
what is the aetiology of dry eye
is recognized as a disturbance of the Lacrimal Functional Unit (LFU)
an integrated system comprising the lacrimal glands, ocular surface and lids
what is the lacrimal functional unit and what is it’s 3 main functions
an integrated system comprising the lacrimal glands, ocular surface and lids
The overall function of the LFU is to:
- preserve the integrity of the tear film
- the transparency of the cornea
- the quality of the image projected onto the retina
what can happen as a consequence of any disease or damage to any component of the LFU
Disease or damage to any component of the LFU (including the afferent sensory nerves, the efferent autonomic and motor nerves) can destabilize the tear film and lead to ocular surface disease that expresses itself as dry eye
what is the pathogenesis of dry eye
that inflammation plays a role in the pathogenesis of dry eye
Tear film hyperosmolarity causes hyperosmolarity of the ocular surface epithelial cells and stimulates a cascade of inflammatory events
The pathogenesis also has a immune component
A secretary dysfunction = reduced tear volume/production
what 2 things is dry eye classified into
1) Aqueous deficient dry eye: failure of lacrimal secretion
A SjÖgren’s Syndrome (SS)
B Non-SjÖgren Syndrome (= 80%)
2) Evaporative dry eye A Intrinsic (due to intrinsic disease causing evaporative loss directly e.g. lid margin disease/MGD does not release component of tear) B Extrinsic (increased evaporation by pathological effects on the ocular surface e.g. contact lenses, effects of topical drugs)
what is SjÖgren’s Syndrome, what is it commonly associated with and what is the only way to diagnose it
an autoimmune disorder consisting of dry eye (KCS) and dry mouth (xerostomia), which often involves nasal and vaginal mucous membranes also
commonly associated with systemic diseases such as rheumatoid arthritis and systemic lupus erythematous
only way to diagnose is by blood test
what is the commonest cause of tear deficient dry eye
Acquired primary lacrimal disease
with Acquired primary lacrimal disease:
what is the only thing involved
what does histology of this show
what is shown as normal with this condition
what is the most common cause of acquired primary lacrimal disease
- Commonest cause of tear deficient dry eye
- Only lacrimal glands involved
- Histology shows infiltration by inflammatory cells, loss of normal structure, atrophy and fibrosis
- Blood tests normal
- Most common cause is age-related changes in lacrimal gland morphology and secretion
what is the most common cause of evaporative dry eye
Meibomian gland dysfunction
which type of drugs are found to cause dry eye
list 5 examples of these drugs
how does it cause the dry eye in patients
- Several commonly systemic drugs
- Beta blockers
- Antihistamines
- HRT
- Anti-psychotic medications
- Isotretinoin (treatment for acne)
- May exacerbate symptoms in patients with pre-existing dry eye and in contact lens wearers reduce wearing time
how is antihistamines found to cause dry eyes
by the tears evaporating quickly
name a surgery that can cause dry eye
laser refractive surgery
how does LASIK cause dry eye
LASIK has a neurotrophic effect on the cornea, along with other changes in corneal shape, that affect tear dynamics causing ocular surface desiccation
what is a major risk factor of more severe dry eye after LASIK surgery and what should be done to prevent this
- Preoperative dry eye condition
- should be identified prior to surgery
list 4 main symptoms of mild dry eye syndrome
- itching
- soreness
- burning
or - intermittent blurred vision
what are the symptoms of moderate dry eye syndrome
increased discomfort and frequency of symptoms, and visual effects may become more consistent
what are the symptoms of severe dry eye syndrome
increasing frequency of symptoms or constant symptoms, and visual symptoms may be disabling (need to be managed more closely in hospital)
list 8 signs of dry eye
- Conjunctival injection
- Conjunctival staining
- Corneal staining
- Reduced tear meniscus along upper and lower eyelid
- Filaments
- Reduced tear BUT
- Reduced Schirmer score
- MGD
how can you measure tear meniscus as a sign of dry eye
use flourescein to measure the tear meniscus height
which is the best way to measure TBUT
the non invasive way, which is without flourescein as that can disturb the tear film
list 6 things that should be done in your history and 2 things done in examination in relation to someone with dry eye
History
- Dry eye questionnaires
- Symptoms and signs
- Exacerbations
- Duration
- Severity
- Ocular, medical and medication history
Examination
- Slit lamp
- Diagnostic tests: tear meniscus height, BUT, staining (fluorescein, lissamine green), Schirmer test
