Ocular Trauma & Sudden loss of vision

Question 1

What should you include in ocular trauma hx?

Answer 1

1. Mechanism and timing of trauma
2. Any non-ocular injury sustained?
3. Any first-aid given?
4. Past ocular + medical hx
5. Drugs/Allergies
6. When did they receive tetanus in the past?

Question 2

What should you include in ocular trauma examination?

Answer 2

1. ABC + systemic examination
2. Visual acuity with and w/o pinhole
3. Assess external structures: orbit, eyelids, lacrimal apparatus, conjunctiva, cornea
4. If hx suggests, check for foreign body by look under the eyelid
5. Opthalmoscopy: anterior segment (ant chamber, iris, lens, vitreous) and fundoscopy (retina, optic disc, introcular P)
6. Pupil examination, eye position include proptosis (orbital hameatoma), eye movements
7. visual fields, sensation (corneal reflex, maxillary n)

Question 3

If a patient presents with a corneal foreign body, what might you find on examination? What investigations might you order if you suspected intraocular body?

Answer 3

metallic foreign body on cornea +/- rust ring, anterior uveitis. Can have photophobia due to corneal irritation.
Always look under eyelid (subtarsal).
If hammering metal - high velocity might have led to intraocular FB- check with XR.

Question 4

What investigations and management are required for a chemical injury to the eye?

Answer 4

pH
wash out with water/ saline immediately, continuing to irrigate and check pH.
Later management: inspect eye for particulates. Topical abx, steroids, mydriatic agent, oral vitamin C
Acids coag proteins and tend to generally have less penetration. Alkali can penetrate thru ant chamber.
Complications: corneal clouding (epithelium loss- fluorescine dye) + Neovascularization. Alkali chemicals are lipophilic and penetrate cell membranes and denature the collagen matrix of the cornea facilitating further chemical penetration. Affected tissues can undergo liquefactive necrosis, in which the inflammatory response triggers release of proteolytic enzymes, leading to a cascade of damage

Question 5

What are the hx and examination findings of blunt trauma?

Answer 5

PC: visual disturbance/ loss of vision, pain, tenderness at rest/ movement, diplopia. Any use of eye protection at time of injury?
Rule out presence of penetrating injury + associated injuries.
hx of previous trauma/ surgery may influence outcome.
Ext ocular examination: 1. Lid trauma- periorbital bruising, facial #
Anterior segment examination: presence of hyphaema (blood in anterior chamber). Do not dilate pupil if present
Pupil: RAPD, traumatic mydriasis (anisocoria and fixed dilated pupil)
Fundus: absent red reflex due to vitreous haemorrhage, retinal detachment.
EO movements: restricted due to # of orbital floor/ wall, retrobulbar haematoma, CN palsies.

Question 6

What are the investigations and management of blunt trauma?

Answer 6

Investigations: ocular US
XR/CT, CT gold st if # and to rule out head injuries in these cases
superficial injuries: topical abx (to prevent 2 ° infection) and analgesics
lid lacerations: may req suturing

REFER the following conditions: 
traumatic hyphaema (blood anterior chamber) 
retrobulbar haematoma with increased ICP
perf of cornea/ ruptured globe (eyeball)
ocular chemical burns
Lens subluxation/ dislocation
laceration of lid margins/ nasolacrimal system
traumatic optic neuropathy

Question 7

What are some of the complications of blunt trauma to the eye?

Answer 7

1. corneal abrasion
2. Hyphaema- blood anterior chamber
3. traumatic mydriasis - sphincter muscle ischaemia due to rupture of blood vessels supplying
4. iridodialysis- detachment of iris root from ciliary body (may req direct surgical closure of defect)
5. Traumatic anterior uveitis/ iritis (tx steroids + pupil dilators to prevent posterior synechiae)
6. Iridocorneal angle recession (shearing of ciliary muscle leading to widening of the anterior chamber and poss trabecular meshwork dysfunction)- which may cause 2° open angle glaucoma
7. Dislocated lens due to disruption of the zonular fibres/ cataract (this is commonly associated with dislocation/ subluxation): coup + contrecoup, and equatorial stretching of the eye subject to blunt trauma causes the formation of a cataract bc it disrupts the fibres/ zonules.
8. Retinal Detachment/ Vitreous haemorrhage: Compression of the globe (coup-contrecoup) in an A-P direction causes the equator of the globe to stretch in a coronal plane. Esp in younger pts w/ formed vitreous and strong adherence of the vitreous to the retina, this bulging in the coronal plane causes inward-directed traction on the retina which results in tears of the retina/ rupture of retinal blood vessels.
9. Retinal Oedema + Haemorrhage (sig damage to visual acuity poss): traumatic disruption of the photoreceptor outer segment (always occurs) and reversible loss of cone pigment in the RPE (if trauma significant). Damage to blood vessels in the nerve fiber layer also occurs with greater force of shock wave.
10. Blow-out # (restricted eye movement) orbital floor into max sinus, periorbital oedema + periorbital haematoma (may trap IR muscle - ischaemia + fibrotic if not E tx)
11. Acute glaucoma 2 to hyphaema where blood cells block trabecular meshwork so monitor ICP.

Question 8

How are some of the complications of blunt trauma managed?

Answer 8

1. superficial corneal abrasions- topical antibiotic
2. lamellar lacerations to the cornea (i.e. allowing aq from anterior chamber to leak through opening in cornea) manage contact lenses and topical abx
3. traumatic iritis- topical “cycloplegics”: muscarinic receptor blockers to dilate pupil + steroid eye drops
4. traumatic hyphaema- waiting for reabsorption of blood with head elevation for 4d to prevent rebleeding. topical mydriatics (dilators) and steroids for 2/52.
5. traumatic cataracts- phacoemulsification.
6. retinal tear- retinal lasers and retinal detachment surgery (E surgery).
7. Blow out # does not usually req surgery unless IR muscle is trapped in which case E surgery req to save muscle from ischaemia and fibrosis. Opacification of maxillary sinus on XR orbital floor # highly likely. CT req for def dx but not always necc.

Question 9

What are some of the outcomes of penetrating eye injury?

Answer 9

lid lacerations w/ poss involvement of lacrimal canalicular system (remember guy who got head butted?)
intraocular foreign body
corneal laceration
wound dehiscence following ocular surgery
sight threaten infection due to breach in cornea (rare)
XR/ CT if introcular FB suspected
lens- cataract/ retinal damage