D - Dry Eye - Week 1 redone Flashcards
What is the 2017 TFOS DEWS II definition of dry eye?
A multifactorial disease of the ocular surface characterised by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play aetiological roles
In regards to dry eye: how do you manage signs without symptoms?
Preventative management as appropriate (e.g. pre-surgery)
How do you manage neurotrophic conditions (dysfunctional sensation)?
Signs indicate management of DED is required
How do you manage a patient with dry eye symptoms but it’s another ocular surface disease?
Refer/manage according to differential diaignosis
How do you manage symptoms without signs/pre-clinical state?
Observe/offer education/preventative therapy
How do you manage dry eye patients with no signs and neurotrophic pain?
Refer for pain management
Provide an example how a patient can have signs of dry eye but no symptoms
Nerve damage causing loss of sensation
What is the lacrimal functional unit comprised of?
Lacrimal gland, ocular surface components, MGs, eyelids, assoc. sensory (CNV) and autonomic (CNVII) innervatino
What does the lacrimal functional unit regulate? (3)
Tear secretion
Tear distribution
Tear clearance
What can disruption to one or more components of the lacrimal functional unit lead to?
Loss of tear film homeostasis
From where does the cornea receive sensory input?
From the ophthalmic division of the trigeminal nerve
Is staining enough to diagnose dry eye?
No
What is the difference between nociceptive pain and neuropathic pain?
Nociceptive: pain in response to actual or threatened tissue damage
Neuropathic: pain in response to damage to the somatosensory pathway
Which is more transient: nociceptive pain or neuropathic pain?
Nociceptive (whereas neuropathici is more chronic)
Which type of pain activates the corneal nerves? Nociceptive or Neuropathic?
Nociceptive
Is topical treatment that useful in treating neuropathic pain?
Not really, since it’s higher up
List features of clinical history that would make you suspect neuropathic pain (2)
Heat or prickling sensation
Association with other neuropathic disorders (e.g. migraine)
How can you anatomically evaluate corneal
Corneal confocal microscopy
What functional test can you do for corneal neuropathy? What outcome would indicate neuropathy?
Test central sensitisation with either topical anaesthetic or sclerlal lenses. if level of pain stays the same, then it’s neuropathic
List the 3 steps in the diagnostic algorithm for dry eye
Triaging questions
Risk factor analysis
Diagnostic tests
What are the 4 most important trading questions for dry eye?
Any mouth dryness or swollen glands?
Vision affected? Does it clear on blinking?
Itchy/swollen/crusty on waking/any discharge?
Have you been diagnosed with any general health conditions?
List 5 other important triaging questions for dry eye
How severe is the discomfort?
How long have your symptoms lasted and was there any triggering event??
Are the symptoms or redness worse in one eye than the other?
Do you wear contact lenses?
Are you taking any medications?
List 4 non-modifiable risk factors for dry eye?
Age > 40yo
Female
Asian
Systemic (DM, rosacea, rheumatoid, sjogren’s, thyroid)
List 5 modifiable risk factors for dry eye
Meds
Smoking
VDU
Contact lens
Environmental factors (humidity, air currents/drafts/air conditioning)
What screening test is used for dry eye? What values do we expect for dry eye?
Questionnaire:
Either OSDI >/= 13 or DEQ-5 >/= 6
Describe the order of homeostasisi marker tests for dry eye while providing their normal values
- NIBUT (<10 sec = dry eye)
- Osmolarity (>308mOsm/L or interocular difference >8 = dry eye)
- TBUT (<10 sec = dry eye)
- Ocular surface staining (>5 corneal spots; >9 conj spots; or lid margin >/= 2mm length & >/= 25% width)
NB: pick one of TBUT and NIBUT. Also sometimes osmolarity isn’t available in clinic etc. Also should find out how to do osmolarity
What does a score of >/= 12 on DEQ-5 indicate?
Possible sjogren’s
Where is NIBUT performed? How many measures do you take?
Performed on topographer (observe the quality of the motors over time). Take the average of 3 measures
What happens to the results of osmolarity if you accidentally poke the patient in the eye?
Patient will get hyposmolarity so it will look like their osmolarity reading is lower than it actually is. This is due to reflex tearing from being poked in the eye
What are the key parameters to look at in meibomian gland evaluation? (3)
Evaluate lid margin
Express MGs
Examine secretion colour and consistency
How is the MGS (Meibomian Glands yielding liquid Secretion score) assessed? What score is classified as clinically significant MGD?
Express 5 glands inferiorly (5 nasal, 5 central, 5 temporal). Score is as follows:
3 = clear liquid secretion
2 = cloudy liquid secretion
1 = toothpaste consistency
0 = no secretion
MGS < 12 = clinically significant MGD
What does Meibography assess?
Extent of drop out as a percentage of the eyelid (loss of secretory acinar tissue)
Is tear meniscus height a reliable parameter for dry eye assessment?
Not particularly, too variable
What happens if you use too bright a light when measuring tear meniscus height?
Reflex tearing will make the meniscus height larger
When should you expect dry eye when doing the phenol red test? (Values wise)
<10mm/15sec
When should you expect dry eye/sjogren’s in the schooner test?
<5mm/5min
