Ophthalmology - Eye trauma

Question 1

Which is worse: acid or alkali eye burns? Why?

Answer 1

Alkali cause liquefactive necrosis and thus penetrates the eye to a greater extent than acids which cause coagulative necrosis and so remain localised on surface of eye.

Question 2

A 25yo male presents to ED with eye pain after having accidentally splashed bleach into his eye.

What is your immediate management?

Answer 2

Immediate (before full Hx + examination)

1. test pH then instill topical anaesthetic
2. irrigate with at least 2L of water/normal saline/Hartmann’s solution through IV tubing or until normal pH is restored
3. inspection: evert the lids + inspect fornices, remove any particulate matter
4. test pH at end of irrigation and 5mins after completion of irrigation
   - if pH neutral/near neutral (max 7.4): examination + further Tx, recheck pH after 20mins
   - if pH abnormal: repeat irrigation with another 2L until pH normal

Question 3

A 25yo male presents to ED with eye pain after having accidentally splashed bleach into his eye.
His eye has been irrigated to reduce pH to normal and his eye has been thoroughly examined.
How should you manage him next?

Answer 3

1. topical Abx e.g. chloramphenicol 5% QDS
2. topical cycloplegia (for comfort/AC activity) e.g. cyclopentolate 1% TDS or atropine 1% OD
3. topical lubricants 1-4 hourly day + night and liquid paraffin nocte
4. oral analgesia e.g. paracetamol, codeine

Admit for further Tx if Dua grade II+

Question 4

A 37yo male presents to ED with facial pain + double vision after having been punched in the right eye.

What is the most common site for an orbital fracture?

Answer 4

Orbital floor (maxillary bone easily fractured as weakened by maxillary sinus).

Question 5

A 37yo male presents to ED with facial pain + double vision after having been punched in the right eye.
O/E he has vertical diplopia with eye movement, enophthalmos + facial anaesthesia. Explain why.

Answer 5

Orbital blow-out fracture with tissue prolapse + entrapment causing mechanical restriction of upgaze (so vertical diplopia).

Infraorbital anaesthesia occurs due to infraorbital nerve damage in infraorbital canal.

Question 6

How would you investigate + manage a patient presenting with an orbital blow-out fracture?

Answer 6

Ix

• CT: ID fractures, prolapsed orbital fat/EOM and haemorrhage
• facial X-rays: droplet sign, fluid level in maxillary sinus, visible fracture
• orthoptic assessment: mechanical restriction on field of binocular vision

Mx

• Abx prophylaxis e.g. CO-AMOXICLAV
• refer to maxillofacial surgeons to consider surgical repair
• orthotic f/u

Question 7

What are the indications for surgical intervention in orbital floor fractures?

Answer 7

Immediate:

• persistent oculocardiac reflex (bradycardia associated with EOM traction or ocular pressure)
• young patient with ‘white eyed’ trapdoor fracture
• early large enophthalmos causing significant facial asymmetry

Early (<2/52):

• persistent symtpomatic diplopia with restriction within 30 degrees of 1 position
• significant enophthalmos (>2mm and symptomatic) or fracture involving >50% of orbital floor

Observation:

• minimal restriction e.g. only extreme upgaze
• minimal enophthalmos

Question 8

An 18yo girl presents to ED after being hit in the face by a baseball bat.
O/E: tight swollen eyelid, painful proptosis + resistance to retropulsion, IOP 50mmHg, restricted ocular movements and reduced vision with RAPD.

What has occurred and how would you manage?

Answer 8

Orbital compartment syndrome: soft tissue oedema + retrobulbar haemorrhage… acute increased intraorbital pressure, compromising blood flow… ischaemia + optic n. damage.

Mx

1. immediate lateral canthotomy + lower/upper cantholysis
2. 2nd line: IV mannitol + IV acetazolamide
3. orbital CT scan