Week 1.02 Wet And Dry Eye Flashcards
(17 cards)
What are the components of tear film
Lipid layer – Meibomian glands, Zeiss and Moll Glands involved.
Aqueous layer – Lacrimal glands
Mucin layer – Goblet cells and Lacrimal gland
Lipid layer
- reduces evaporation
- lower surface tension
- Lubricate eyelids
Aqueous layer
- Oxygen supply
- Antibacterial contains lysosyme and immunoglobulin
- Remove debris
- eliminate minus surface irregularity
Mucin layer
- create a hydrophilic surface
- lubrication
What is the normal tea break up time?
10 seconds
What are the causes of wet eyes?
Hyperlacrimation
Epiphora
What is hyperlacrimation?
Reflex tearing due to underlying pathology e.g.foreign body, inflammatory disease
Too much tears
What is epiphora?
Compromised tear drainage
Punctum occluded or out of position
Duct obstruction
Pump failure
Not enough tears being drained away
In a normal eyes tear production is…
Greater than the evaporation
What are the tests for wet eyes?
Slit lamp - standard slitlamp examination can test for their eyes
Fluorescein dye disappearance test - ask patient to blow the nose and clear with tissues patient should blink normally throughout the test, in still equal amount of fluorine into both eyes and wait for five minutes, compare the height of the two tear meniscus of the lower eyelids
John test 1- instill fluorescein wait five minutes occlude one nostril at a time and blow their nose check the tissue for fluorine under the button lamp. If Fluorescein not present, the lacrimal sac obstructed surgery may be needed or lacrimal syringing.
What are the causes of dry eye?
Not enough or too much being evaporated
- Increased evaporation
- Hyposecretion
- oculur surface disorder
Increased evaporation
Lipid layer deficient
Meibomian gland dysfunction - look for MGD or notching
Hyposecretion
Deficient aqueous layer - deteriorates over time
Age related
Sjögren’s syndrome
Lacrimal gland destruction - thyroid disease
Obstruction of flow from gland - scarring
Ocular surface disorder
Deficient mucin layer
Lasik surgery reduces number of functioning goblet cells and reduces mucin layer
A test for dry eyes
Case history
Slit lamp
Ocular surface damage
Dyes - Fluorescein identifies damaged tissues, Lissamine green stains devitalised cell - instil into lower fornix and check after 1 minute enhance using wratten filter
Rose bengal - stains devitalised cells, px blink observe white light
Non-invasive tear break up(NIBUT) - grid pattern projected on cornea, time taken for disruption of pattern
Tear thinning time- time from blink to 1st distortion of keratometer mires
Tear break up time - fluorescein, time appearance of dark spots in tear film
Tear meniscus height
Tear volume tests(aqueous layer) - phenol red thread - 3 mm section bent over temporal side for 15secs, red portion measured in mm
Schirmer test - bend strip, place in conjunctival sac, remove after 5 mins, measure wet portion.
> 5mm dry eye
10-15mm normal
Requires repeated measures
Dry eye treatment options
- Lid hygiene - warm compresses, lid scrub, cotton bud water and baby shampoo
- Puntal plugs - short term dissolvable, long-term silicon, perforated - allowed drainage for wet eyes with punctal problems
Medication associated with dry eye
Orphenadrine - for Parkinsonism
Amiodarone - anti arrhythmic
Bendroflumethazide - diuretic
Retinol - used in treatment of psoriasis
Isoretinoin - acne treatment
Antidepressants
Antipsychotic
Oestrogen replacement
