Dry Eye Disease Investigations Flashcards
Why is it important to asses tear film?
- Complete tear film is essential for:
o Antibacterial properties – to fight infection
o Transporting nutrients to cornea – cornea is avascular so needs nutrients from somewhere
o Optical performance of eye – if not good tear film then not smooth refraction of light into eye & so blurred vision is symptom of DE – if tear film is damaged then can affect vision overall
o Successful CL wear
o Removing FBs - Dry eye is due to disorder or disturbance of tear film
Describe the structure of tear film?
- Outer oily layer
o Produced by meibomian glands (if have MGD it is lipid layer you lack leading to ↑ evaporation)
o Smoothes tear surface and decreases evaporation - Aqueous (Watery large middle) layer
o Produced by lacrimal gland
o Carries nutrients & oxygen to cornea
o Washes away particles & irritants - Inner mucous layer
o Produced by conjunctiva (in particular goblet cells)
o Provides protection & ensures eye remains moist
o Vital for stability of tear film (vital in ensuring tear film remains on)
Now being described more as a mucin gradient through the tear film
Describe Dry Eye Disease (DED) overall?
- Complex group of conditions
- Characterised by a dysfunction of one or more of components of tear film
- Multifactorial – can be multiple things causing it
- Types:
o Evaporative (e.g. due to MGD)
o Aqueous deficient (e.g. due to age)
o Mixed – both of above
Aqueous deficient px has reduced production of tears
Evaporative px has increased evaporation with normal production of tears
Reduced lacrimal flow but also MGD
What is dry eye caused by?
- Too few tears
o Resulting from:
Nerve damage
Refractive surgery - Too high an evaporation
o Resulting from:
Environment e.g. air con
Lids conditions e.g. bleph - Both of the above causes of DE feed into cycle in same way, both cause hyperosmolarity – in turn releases various inflammatory markers that lead to goblet cell loss & epithelial damage to cornea & apoptosis (cell death)
o These factors cause tear film instability or low tear break-up time
o Tear film instability also causes hyperosmolarity – then stuck in cycle – therefore management is difficult if have to break cycle - Preservative reaction or allergy can also cause tear film instability
What are the risk factors for dry eye?
- Female – especially during menopause – hormonal element
- Age
- Smoking
- Caffeine consumption
- Diabetes mellitus – can be severe
- Topical medications – especially those with preservatives
- Systemic medications
- Acne rosacea – associated w/ MGD
- History of arthritis – any autoimmune conditions e.g. Sjogren’s, Lupus
What is aqueous deficient dry eye (ADDE)?
- ADDE primarily refers to a failure of tear production by the lacrimal gland
- This leads to a reduction in the volume of tears which, in turn, causes hyperosmolarity of the tears due to evaporation
- This hyperosmolarity induces an inflammatory response on the ocular surface
- ADDE can be sub-divided into Sjögren’s syndrome dry eye and non-Sjögren’s syndrome dry eye
Describe aqueous deficient dry eye (ADDE) and Sjogren’s?
- Sjögren’s syndrome is an autoimmune condition involving damage to the secretory glands throughout the body, such as the salivary, vaginal and lacrimal glands.
- Primary form of Sjögren’s syndrome dry eye (SSDE) occurs independently of any other autoimmune condition, but alongside a reduction in saliva production
- Secondary SSDE occurs alongside an autoimmune condition, such as systemic lupus erythematosus or rheumatoid arthritis
Describe aqueous deficient dry eye (ADDE) and non-sjogren’s?
- Acinar atrophy and periductal fibrosis can cause an obstruction affecting tear production scarring in lacrimal gland/duct area – tears then can’t reach surface of eye
- Familial dysautonomia – problems with reflexes throughout body – reflex tearing & normal basal secretion of tears - rare
- Congenital alacrima – rare – absence of lacrimal gland
- Secondary causes include:
o Obstruction of the lacrimal gland ducts from chemical/thermal trauma (scarring)
o Trachoma
o Contact lens wear
o Diabetes
o Cranial nerve damage
o Systemic medication use - Secondary obstruction of the lacrimal gland itself, due to conditions such as lymphoma (cancer), sarcoidosis, graft-versus-host disease and acquired immunodeficiency syndrome
Describe evaporative dry eye (EDE)?
- EDE is a consequence of increased evaporation of tears from the ocular surface, when the lacrimal gland is functioning normally
o Normal level of tears, they are just evaporating too quickly - This increase in tear evaporation leads to tear hyperosmolarity
- EDE can be due to either an abnormality with the ocular structures (intrinsic) or an external factor (extrinsic)
Describe intrinsic evaporative dry eye (EDE)?
- Meibomian gland dysfunction
o Blockages in glands, don’t have lipid layer to protect aqueous which leads to increased evaporation
o Congenital lack, malformation or scarring of the meibomian glands
o Telangiectasia (see in pic) – classic sign of MGD – lots of BVs on inflamed lid - Proptosis – thyroid eye disease -> lid retraction -> exposure of ocular surface leading to increased evaporation
- Low blink rate – commonly when looking at screens
Describe extrinsice evaporative dry eye (EDE)?
- Contact lens wear – piece of plastic disrupting tear film
- Ocular surface disease e.g. allergy – look under eyelids to look for papillae
- Systemic drug use e.g. isotretinoin (Roaccutane – acne tx)
- Topical drug use – anything that’s preserved
- Vitamin A deficiency – may not be as common in UK
- Environment e.g. air conditioning, central heating (low humidity, dry atmosphere)
What questions should be asked in px reporting dry eye?
o Dry eye is chronic problem – rarely acute
* Binocular? Is one eye worse?
o DE is binocular unless really unusual cause – e.g. only wear CL in one eye
o Can be asymmetric
* Describe your symptoms in your own words
o If burny, gritty, firey – then aqueous deficient
o If watery eye – leads down different route
o Gives idea on how effects their life
* What have you tried? How often did you use it? Did it work?
o E.g. drop, gel, hot compress
* Does anything make your symptoms worse/better?
o Anything triggering them e.g. only in work under AC unit
o Anything improve it? – better on holiday = more humidity
* General health – diabetes? Autoimmune conditions?
* Medications?
o Systemic meds – oral contraceptive, beta blockers, antihistamines
o Never advise px to stop using meds – but if tie in start of meds with start of dry eye can communicate to doctor & see if alternative med or if we need to manage the dry eye while they are on the meds
* VDU use? Occupation? CL wearer?
* Allergies?
o Most of these will also be allergic to preservatives
o If px has red watery eye and may be thinking evaporative dry eye – consider allergic conj
May need mast cell stabiliser or antihistamine instead of DE tx
What are the symptoms of Dry Eye Disease?
- Including, but not limited to:
o foreign body sensation
o grittiness
o pain – if corneal involvement
o itching – allergy as differential
o blurred vision
o photophobia – if corneal involvement
o lacrimation
o redness - ADDE: burning, gritty sensation
- EDE: watery, uncomfortable eyes. May be worse in certain environments
- Mucus: sticky, uncomfortable eyes. May report a stringy discharge
o Not as common – may be misdiagnosed as bacterial conj - If the cornea is affected then expect reports of pain, photophobia
o BUT, in long standing severe DED the cornea desensitizes (nerves damaged) so the most severe cases may not report the most severe symptoms
Sxs & signs of DED may mismatch – if lots of damage make sure px understands severity of problem
When and why would you use a symptom questionnaire?
- Complete after H&S
- Gives quantifiable number on symptoms
- Less subjective way to measure symptoms
- 3 main ones:
o Ocular Surface Disease Index (OSDI) – asks about environment px is in
o DEQ-5 – shortest, just 5 Q’s
o McMonnies – asks about meds, swimming, alcohol intake (risk factors) – asks about age and gender as well (age increases so score automatically increases too) - CANNOT SWAP AND CHANGE WHICH ONE USE WITH PX – consistency is key
What is the differential diagnosis of Dry Eye Disease?
- Viral conjunctivitis – due to watery discharge
o Short term, not chronic – usually starts in one eye – other people in household
o Follicular reaction - Bacterial conjunctivitis – sticky discharge
- Allergic conjunctivitis – watery, itchy eye – more chronic when perennial so easily confused
o Papillae reaction - Eyelid abnormality – ectropion, entropion – look for on slit lamp
- Nocturnal lagophthalmos – technically causes dry eye but not a type of dry eye itself – problem with closure of eyelids when sleeping – causing dry eye – tape eyes during night
LID EVERSION is v useful for helping with diagnosis
When do lid eversion in dry eye – usually see redness & roughness rather than follicular or papillae
