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
Globe rupture
Clinical features:
- **Soft eyeball
- **Distorted pupil
- **Exposed intraocular content
- **Leaking fluid / jelly
Management:
1. **Tetanus prophylaxis
2. X-ray (ensure no foreign body)
3. **Plastic eye shield
4. ***Repair
- Primary repair: restore integrity of eyeball
- Secondary repair: restore function
Aim of surgery:
- Restore globe integrity
- Prevent infection (Endophthalmitis)
- Prevent further prolapse of intraocular content
- Restore function
Complications:
1. ***Blindness (depending on rupture severity, rupture site usually at insertion of EOM (∵ weakest site))
-
**Sympathetic ophthalmia
—> Body produce Ab against choroid in eye (not in contact with blood circulation before injury ∵ blood-retinal barrier)
—> Attack ruptured eye + **unruptured eye
—> Evisceration / ***Enucleation if eye is not viable (painful blind eye) (to prevent stimulation of immune system)
—> Enucleation can prevent small risk of sympathetic ophthalmia in contralateral eye
Intraocular foreign body (IOFB)
Direct mechanical damage —> creating:
1. Blood —> can ↑ IOP
2. Scar
—> damage optic nerve / retina
Depend on site of foreign body:
1. Cornea —> Corneal scar
2. Lens —> Cataract
3. Vitreous
—> Vitreous haemorrhage
4. Retina
—> Retinal haemorrhage
—> Retinal break
—> Retinal detachment (rheumatogenous and tractional)
Management:
1. **Tetanus prophylaxis
2. Slit lamp examination, Gonioscopy, Fundoscopy
3. Ultrasound, X-ray, CT scan (ensure no foreign body)
4. **Plastic shield
5. Removal of IOFB
6. ***Intraocular antibiotics
7. Repair external wounds
- Anterior chamber: Removal
- Lens: Removal +/- Lens extraction +/- Intraocular lens implantation
- Vitreous / Retina: Vitrectomy +/- Retinal surgery
8. Observe for sympathetic ophthalmia
Corneal foreign body
- foreign body on top of cornea
- commonly seen in renovation workers (welding shot onto eye)
Treatment:
1. Removed under topical anaesthesia
2. Topical antibiotic
Complications:
1. Perforation
2. Infection
3. Corneal scar, Astigmatism
Non-mechanical injury: Chemical burn
***Alkali more serious than Acid
Acids:
- Common acids: Battery fluid (H2SO4), Toilet cleaner (H2SO4), Bleach / Pool cleaning fluid (NaHOCl)
- Severity depends on:
—> Concentration of acid
—> Protein affinity of acid anion
—> Combines with protein —> forms and ***insoluble layer on superficial tissue —> limits further penetration by acid
Alkalis:
- Common alkalis: Oven / Drain cleaning fluid (NaOH), Plaster (CaOH2), Fertiliser (NH4OH)
- **Penetrates tissue rapidly —> combine with **lipoid cell membrane —> disruption of cells —> ∴ Alkali more serious than acid
Classification:
- ***Roper Hall classification (grade 1-4)
—> Epithelial damage
—> Limbal ischaemia (location of stem cells —> help to regenerate corneal epithelium)
—> Anterior chamber details (e.g. hyphaema)
Management:
1. **Irrigation (initial pH: similar to unaffected eye)
2. Topical antibiotics (for prophylaxis)
3. Steroid (prevent inflammation, scarring)
4. High dose Vit C (for healing)
5. **Cycloplegic (for pain control)
6. Refer to ophthalmologist
Complications:
1. **Cataract
2. **Corneal haze / scar
3. ***Glaucoma
4. Symblepharon (eyelid sticking to cornea)
5. Lash misdirection / Lid malposition (scarring in posterior lid cause lid in-rolling)
6. Corneal ulcer / melt
7. LSCD (Limbal stem cell deficiency)
8. Phthisical eye (i.e. non-viable eye)
Treatment of complications:
- ***Keratoprosthesis (e.g. OOKP, plastic prosthesis)
Lid laceration / Canaliculus injury
Aim:
- Prevent lid deformity leading to complication —> need proper apposition of lid margin
—> Entropion (eyelid turning in) —> Corneal problem from constant mechanical scratching
—> Ectropion —> Cicatricial ectropion —> Exposure keratopathy
Management:
- Suture
- Re-canulate puncture
- Pre-auricular graft (for lost eye lid)
Orbital fracture
Commonest site of fracture: Medial + Inferior part of orbit (∵ thinnest)
Signs:
1. **Enophthalmos (∵ herniation of orbital contents: “tear drop” sign on skull x-ray)
2. **Restricted eye movement
3. Bony tenderness
4. Surgical emphysema
5. ***Infraorbital (V2) numbness
6. Blood in maxilla
Symptoms:
1. Orbital pain
2. Pain on ocular movement
3. Diplopia (esp. in upgaze, ∵ orbital haematoma, muscle incarceration)
4. Paresthesia over maxilla (∵ damaged infraorbital nerve)
Indications for surgical repair:
1. Diplopia on primary gaze
2. Unacceptable enophthalmos (>2 mm sunken)
3. Large orbital floor defect (>1 cm^2)
Management:
1. Surgical repair
2. Avoid nose blowing (∵ maxillary sinus connected with orbit now —> create air in retrobulbar space)
3. Prophylactic systemic antibiotic
4. Look for associated injuries
Orbital cellulitis
Pre-septal cellulitis
- Periorbital cellulitis
- Management: Oral / IV Antibiotics
Post-septal cellulitis
- More severe Periorbital cellulitis
- Chemosis (swelling of conjunctiva (∵ subconjunctival fluid))
- Proptosis
- EOM limitation (∵ ↑ intraorbital pressure)
- +/- Visual impairment / RAPD (∵ compression of CN2)
- Management: ***IV Antibiotics, CT scan, Debridement / Drainage (for sphenoid / frontal / maxillary sinus abscesses)
