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Flashcards in Dry eye disease Deck (38)
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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
- 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
- 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
- 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


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

- Dry eye questionnaires
- Symptoms and signs
- Exacerbations
- Duration
- Severity
- Ocular, medical and medication history

- Slit lamp
- Diagnostic tests: tear meniscus height, BUT, staining (fluorescein, lissamine green), Schirmer test


list 4 diagnostic tests that can be done to examine dry eye

- tear meniscus height
- staining using flourescein or lissamine green
- schirmer test


why is lissamine green used for diagnosing dry eye

it stains the conjunctiva area which is affected/damaged by the dry eye


what 5 tests are done for aqueous deficient dry eye and what is the characteristic findings for each

- Tear break up time
less than 10 seconds considered abnormal (but 3x for reliability)

- Ocular surface dye staining
pattern of exposure zone (interpalpebral), corneal and bulbar conjunctival staining typical

- Aqueous tear production and clearance (Shirmer test)
5mm or less with anaesthesia considered abnormal

- flourescein clearance test/tear function index
test result is compared with a standard colour scale

- lacrimal gland function
decreased tear lactoferrin concentrations


what 3 tests are done for evaporative tear deficiency dry eye and what is the characteristic findings for each

- Tear break up time
less than 10 seconds considered abnormal (but 3x for reliability)

- Ocular surface dye staining
staining of inferior cornea and bulbar conjunctival typical

- Lacrimal gland function
decreased tear lactoferrin concentrations


what 2 things does the treatment of dry eye depend on

- severity
- signs and symptoms


how is dry eye severity determined

by a scale from 1-4*

looking at factors such as:
- discomfort, severity and frequency
- visual symptoms
- conjunctiva injection
- conjunctival staining (severity and location)
- corneal/tear signs
- lid/meibomian glands
- shirmer test