Ocular Surface Disorders

Question 1

Describe the function and anatomy of the lacrimal system

Answer 1

tears provide delivery/excretory route for nutrients/metabolic waste, lubrication and smooth surface

Question 2

Describe the tear film layers and aqueous flow

Answer 2

95% aq tears from lacrimal gland/5% from accessory

outer lipid: meiobian glands prevent evaporation
inner mucous: GCs of conjunctiva hydrophilic

tears flow in marginal strips entering canaliculi via capillary action/suction

lacrimal pump suction into lacrimal sac via orbicularis (blink)

Question 3

Explain dry eye symptoms and aq tear deficiencies

Answer 3

irritation, fatigue, blurred vision, reflex tearing

tear deficiency (Conjuctival dilation/pleating)

AQ tear Deficiencies:
age, CL,
drug related (CT/haematological/endocrine disorders)

Question 4

Explain lipid and mucous layer disorders

Answer 4

Lipids: blepharitis, acne rosacea
Mucous: conjuctival scarring (VitA deficiency)

Question 5

Explain mild and severe treatments for dry eye

Answer 5

Mild: eyelid hygiene, lower CL use, humidifier
hypromellose (0.3%), sodium hyaluronate (HyloTear), Carbomer, retinol with paraffin/wool fat ointment (VitA-POS)

Severe: medicated eye drops (cyclosporine ~ Restasis)
Plugs, topical steroids, fish oil supplements

Question 6

Describe watery eyes

Answer 6

overproduction of tears (ocular surface inflammation/disease)
defective drainage:
punctal malposition (entro/ectropion ~ lid laxity, poor orbicularis function)
punctal stenosis (primary/congenital or secondary)
blocked lacrimal sac/naso-lacrimal duct
lacrimal pump failure

Question 7

Name 3 eyelid disorders causing discomfort

Answer 7

trichiasis, entropion, ectropion

Question 8

Describe 3 corneal disorders causing discomfort

Answer 8

recurrent corneal erosions: acute ocular pain after waking
exposure keratopathy (neutrophic ulcer): progressive thinning, poor lid closure, can be infected
corneal dystrophies: epithelium/Bowmans layer

Question 9

What are the ocular effects of thyroid eye disease?

Answer 9

reduced lacrimal gland function
dry eye
lid retraction
proptosis causes exposure keratopathy

Question 10

Describe infectious keratitis

Answer 10

Increased risk in extended CL wear
Epithelial injury (poor fit/defects/deposits)
Microorganism (poor CL hygiene, pseudomonas, acanthamoeba)