Ophthalmology SC007: Trauma And Ocular Emergency Flashcards
Eye anatomy
Anterior chamber: Anterior to iris, space between iris and back of cornea
Posterior chamber:
- Posterior to iris, Anterior to lens
Complete eye examination
History taking:
1. Mechanism of injury
2. Other illnesses
3. Glasses
4. Vision
Physical examination:
1. Externa
2. Vision (corrected vision, with + without glasses)
3. Pupil (pupil reflex, RAPD)
4. Motility (EOM: Diplopia, Peripheral gaze, Primary gaze)
5. ***Visual field
- ***Slit lamp
- staining to assess anterior segment (cornea, conjunctiva, sclera), lids, punctum - ***Ophthalmoscopy
- retina: retinal detachment
- vitreous body: vitreous haemorrhage
- optic nerve: swelling - Intraocular pressure (high vs low vs normal)
- **Goldmann Applanation Tonometer
- **Gonioscopy (for angle) - Optical coherence tomography
Approach to eye injuries
Exclude life-threatening injuries
- CT brain
- Neck examination
- Consciousness
***Eye injuries classification
- Globe injury
- Mechanical
—> Open / Closed
- Non-mechanical
—> Chemical
—> Thermal
—> Electrical
—> Radiational - Lid laceration / canaliculus injury
- Orbital injury
- Muscle
- Nerve
- Bone
- Infection
Closed mechanical injury
Mechanical waves transmitted through the globe
—> damage can occur to all intraocular structures
Anterior segment:
1. Subconjunctival haemorrhage
2. Corneal abrasion
3. Hyphaema
4. Iridodialysis, Angle recession
5. Lens
- Dislocation
- Traumatic cataract
Posterior segment:
1. Traumatic optic neuropathy
2. Choroidal rupture
3. Vitreous haemorrhage
4. Retina
- Retinal edema (Commotio retinae)
- Holes
- Detachment
Corneal abrasion
Most common eye injury
Cornea: 5 layers, abrasion typically on most superficial layer (i.e. epithelial layer)
- if deeper layer involved —> corneal scarring will occur afterwards
Symptoms (very non-specific, have to rely on PE):
- **Pain
- **Tearing
- ***Photophobia
- Blepharospasm
Assessment:
- VA
- ***Stain
Treatment:
- Relief pain: **Analgesics, Patch eye
- Promote healing / prevent infection: Avoid rubbing, Patch eye
- Antibiotics: **Chloramphenicol (if defect is large)
Complications:
- Infection
- ***Recurrent erosion syndrome (within 4-6 months after injury, ∵ epithelium not well adhered to underlying structures —> slough off by itself)
Prognosis:
- Usually heal within 24-48 hours
Conjunctival laceration
- Exclude globe injury (underlying puncture —> can cause intraocular infection)
- Exclude injury of EOM (12, 3, 6, 9 o’clock location) —> check EOM
- Suture if large
Cyclodialysis / Iridodialysis
**Cyclodialysis: Detachment of the **ciliary body from its insertion at the scleral spur
- low pressure, drainage of fluid into suprachoroidal space (space between choroid and sclera)
**Iridodialysis: Separation of the **iris root from its attachment to the anterior ciliary body
Associations:
1. **Angle recession
2. Traumatic **phacodonesis (movement of lens when eye move around)
3. Sphincter tears
4. Pupil distortion
5. Cataract
Treatment:
- Laser
- Suture
Angle recession
Vs Angle closure (Trabecular meshwork is closed)
Ciliary damage and is displaced posteriorly from its insertion
—> can be considered ***milder form of Cyclodialysis
—> Seen with gonioscopy
Can result in ↑ IOP —> Glaucoma
- usually occurs if recession >180o —> drainage system broken
Treatment:
- Observe
- Control IOP
Traumatic hyphaema
Blood in anterior chamber
—> Need to look for bleeding source (e.g. Cyclodialysis, Sphincter tear)
Grade:
- Microhyphaema (only seen on microscope / slit lamp: RBC floating in anterior chamber)
- 1: <33%
- 2: 33-50%
- 3: >50%
- 4: 100% (“eight ball hyphaema”)
Symptoms:
- Decreased vision
- **Photophobia
- Pain
- **Absence of light reflex
Complications:
- **Rebleeding within 48 hours (esp. if on antiplatelet / anticoagulant)
- Possible ↑ IOP —> **Ghost-cell glaucoma (RBC blocking trabecular meshwork)
- 25% chance associated with other ocular injury
Management:
- MUST exclude **ruptured globe
- Exclude other eye injury
—> if no view —> ultrasound to make sure no foreign body in anterior / posterior chamber
- Shield eye
- Bed rest
- **Control IOP (observe for 1 week)
- **Mydriatic (2% Homatropine / 1% Atropine)
—> prevent pupil movement causing rebleeding
- **Anterior chamber washout (if necessary / persistent / high IOP)
Traumatic lens subluxation
∵ Rupture of Zonular fibres
Subluxation:
1. Inferiorly
- Anteriorly
- ***Acute angle closure (lens press against iris —> iris press against angle)
- Iridocorneal touch, Lenticulocornea touch —> inflammation of cornea —> corneal edema
- Complicated by endothelial failure (∵ prolonged touching, endothelium does not regenerate) - Posteriorly
- Dropped lens (into vitreous / even stick onto macula)
Symptoms:
1. Visual distortion, ↑ Astigmatism
2. ***Phacodonesis (lens shaking on eye movement)
Management:
- Suture
Retina / Vitreous damage
Daily examination with fully dilated pupil!
- Retinal edema
- resolves spontaneously (esp. if at periphery)
- look for co-existing retinal break - Retinal haemorrhage
- resolves spontaneously
- look for co-existing retinal break
- ***Terson syndrome (vitreous haemorrhage with SAH ∵ ruptured cerebral aneurysm) —> need CT brain - Retinal break
- ***floaters, flashes, shadow, ↓ VF
- may co-exist with vitreous haemorrhage - Retinal detachment
- ***floaters, flashes, shadow, ↓ VF
- may co-exist with vitreous haemorrhage - Vitreous haemorrhage
- ophthalmic ultrasound helpful to rule out RD
Traumatic optic neuropathy (TON)
Mechanism of injury:
1. Direct injury to optic nerve anywhere within the intra-orbital length
2. Contusions —> swollen tissues, vasospasm —> Ischaemic injury to retinal ganglion cell axons
Diagnosis:
- Visual loss
- **Afferent pupillary defect
- **Swollen optic disc initially followed by pale disc (replaced by glial tissue)
Imaging:
- Retrobulbar haemorrhage
- Bone impingement on optic nerve
Treatment:
- High dose steroid / Decompression surgery (controversial)
—> Actually high dose steroid found to have no benefit
Open mechanical injury
Causes:
1. High force rupturing globe
2. Sharp injury
3. Previous eye surgery with unstable wounds (e.g. corneal graft)
Symptoms:
1. Drop vision
2. Pain
3. Bleeding
4. Can self seal and miss
Classification of site of penetration / lacerations:
1. Corneal
2. Corneal-scleral (i.e. Limbus)
3. Scleral
4. Posterior
—> Different types of suture used
Ocular traumatology terms
Rupture: Full thickness wound caused by blunt objects
Penetrating injury: Single, full thickness wound usually caused by sharp object (no exit wound)
Perforating injury: 2 full thickness wounds (entrance + exit) usually caused by same object
