Ocular Trauma

Context

Ocular trauma accounts for a significant number of cases both in general practice and A&E. Though the exact figures are unavailable for the UK, approximately 1.6 million people are blinded as a result of ocular trauma worldwide, every year.1 Significant visual impairment and permanent blindness remains a challenge. Of those who suffer ocular trauma males accounted for almost three quarters (72.2%), with the mean age being 34.5years. Falls (37.6%) have now become the predominant mechanism for ocular trauma, overtaking road traffic accidents (25.3%) during 2004-2021. Non accidental injuries have increased in incidence (26.5%). Of note a concomitant head injury was present in 86.6% of cases.22

Definitions

Terms in the BETT (Birmingham Eye Trauma Terminology)2

BETT’s Classification is based on the amount of injury sustained on the eyewall, which is composed of the sclera and cornea.

Globe injury

• Closed globe injury occurs when there is no full thickness injury. It can be sub-grouped as follows:
  • Contusion – no full thickness injury, generally a blunt injury.           
  • Lamellar laceration- involving partial thickness injury of the eye wall with a sharp object.
• Open globe injury involves full thickness injury. It can be sub-grouped as:
  • Rupture- Blunt object causing full-thickness injury of the eye wall.
  • Laceration- Sharp object causing full thickness injury to the eyewall. This can be further divided into:
    • Penetration injury- single entry wound with no exit wound.
    • Intra-ocular foreign body- entrance wound with retained foreign body.
    • Perforating injury- two full thickness wounds, entrance and exit wound.

Anatomy of orbital bones

There are 7 bones that comprise the orbit:

• Sphenoid
• Ethmoid
• Lacrimal
• Frontal
• Palatine
• Maxillary
• Zygomatic

Fig.1 by Dr. Johannes Sobotta  via Wikimedia Commons

The orbit is a pyramid-shaped structure composed of seven bones. The frontal bone and the lesser wing of the sphenoid bone form the roof of the orbit. The floor of the orbit is formed by the maxillary, zygomatic and palatine bones. The ethmoid, lacrimal, maxillary and lesser wing of sphenoid bone is what forms the medial wall of the orbit. The lateral wall of the orbit is formed of zygomatic and greater wing of sphenoid bone.3-4

Anatomy of the eyeball

The cross-sectional view of the eye shows4

• Three main layers:
  • The external layer of the eye is formed by the sclera and cornea.5 The intermediate layer is divided into two parts: anterior part, which is the iris and the ciliary body and the posterior part, which comprises of the choroid.
  • The internal layer, or the sensory part of the eye is the retina.5
• Three chambers of fluid: anterior chamber (between cornea and iris) is filled with aqueous humour, posterior chamber (between iris, zonule fibers and lens), and the vitreous chamber (between the lens and the retina) which is filled with vitreous humour.
• The intraocular lens is suspended by zonules which are attached to the ciliary body.

Fig.2 by Openstax College via Wikimedia

Pathophysiology

Ocular trauma can be classified as4:

Fig.3 The diagram is based on John F. Salmon; Kanski’s Clinical Ophthalmology, A systematic approach, ninth edition. 2019.

Eyelid trauma

Periocular haematoma- The haematoma of the eyelid with or without periocular ecchymosis and oedema are the most common features of blunt trauma to the eyelid.4

Lid Laceration- This can be superficial or extend to involve the lid margin. Lid lacerations can extend from mild to significant tissue loss. Even minimal lacerations represent a risk for infection. It is important to clarify tetanus prophylaxis status and administer if required.4

Orbital Trauma

Orbital blow out fracture - This is usually caused by an object impacting the orbit with force that is greater in diameter than the orbital aperture. This causes a sudden increase in intra-orbital pressure. The floor of the orbit is most frequently affected, as this consists of thin bone covering the infraorbital canal. The lateral wall and roof are usually able to withstand the trauma.  Clinical features depend on the severity of injury. Periocular signs such as ecchymosis, periorbital edema and occasionally subcutaneous emphysema may be present. It is common to experience infraorbital anaesthesia involving the lower lid, cheek, side of nose, upper lip, upper teeth and gums. Diplopia and enophthalmos may also be present.4

Medial wall fracture- Usually associated with orbital floor fractures.

Roof of the orbit and lateral wall fractures – these are rarely encountered and usually result from severe facial injuries from motor vehicle accidents, falls or assaults.

Blunt trauma

The most common causes are assault or sports related injuries.

Clinical features – corneal abrasions, hyphaema (Fig 4), iridodialysis (tear of the iris from the ciliary body) (Fig 5), pupillary abnormalities, lens subluxation or cataract, vitreous haemorrhage, commotion retinae (concussion of the sensory part of the retina which results in grey colour changes to the involved retina), choroidal rupture, retinal breaks and detachment, traumatic optic neuropathy, avulsion of the optic nerve.4

Fig.4 Hyphaema (blood filling 50% of the anterior chamber) via Wikipedia

Fig.5 Iridodilaysis via Wikimedia Commons

Penetrating injury

Signs of penetrating eye injury are peaking of pupil (Fig 6), shallowing of anterior chamber, iris and lens damage seen.  Anterior scleral involvement can have iridociliary and vitreous prolapse. Anterior scleral lacerations have a better prognosis. Posterior scleral lacerations would usually be involved with retinal damage with poor prognosis.

Fig.6 Penetrating eye injury showing iris prolapse through wound 

Learning bite

If a patient has periocular bilateral haematoma (panda eyes) consider a concomitant base of skull fracture.

History

The mode of the injury must be carefully recorded considering its important medicolegal implications.6

• What is the circumstance of injury? (high velocity like using power tools, lawn mower, glass injuries, explosion)
• When did the injury take place?
• What is the mode of injury? (physical, chemical, thermal, nature of object, speed of impact)
• Any other injuries sustained?
• Any treatment received yet?
• What was the previous visual acuity? (rough estimate)
• What are the presenting complaints? (reduced vision, pain, diplopia, flashes/floaters, FB sensation)
• Any past history
• History of TT immunisation, medications, allergies.

Learning bite

Remember to obtain history of whether glasses or goggles were used during injury.7

Examinations

A complete and thorough examination of the eye is vital.

• Visual acuity - Bedside Snell’s chart can be used. If unable, document what can be seen, e.g.: - hand movements, perception of light, can the patient count fingers, read signs in the room, etc.
• Orbits and lids - Do not forget to evert the lids especially in patients with a foreign body. Lacerations, subcutaneous emphysema, orbital rim irregularities should be sought.
• Conjunctiva – Fluorescein stain uptake will be present in small lacerations. It is important to rule out open globe injury and look for haemorrhage.
• Cornea - Fluorescein stain will show abrasions and lacerations. Check for foreign body remembering to lift the upper lid to check for any hidden ones. Perform Seidel’s test* as it will rule out an open globe injury.
• Anterior chamber - look for hyphaema (keep patient upright to see level)
• Iris and pupils - Inspect for size, shape, reaction of pupils including relative afferent pupillary defect (RAPD). Check if pupils are equal, or any iris damage is present. Look for distorted pupil as well.
• Fundus - Loss of red reflex could be due to retinal detachment or blood in vitreous.
• Extraocular movements - Ask about diplopia.
• Orbital compartment syndrome assessment- Check for relative afferent pupillary defect, proptosis (axial), ecchymosis, tense diffuse periorbital edema, conjunctival chemosis and injection, restriction of eye movements and resistance to retropulsion and tense globe on digital tonometry (suggestive of high intraocular pressure).
• Patients with extensive soft tissue damage or hyphaema can restrict evaluation of pupillary reaction. In these cases a coronal view of iris and pupil using ultrasound with contralateral stimulation with torch light may help assess the pupillary reaction.
• Also assess for concomitant injuries like head or c-spine injuries and consider domestic violence and non-accidental injury.

*Seidel’s test - This test is done to assess for occult corneal perforations following injury. It assesses the leakage of aqueous humour from the anterior chamber.4

Technique:

• Explain the procedure to the patient.
• Apply topical anaesthetic.
• Instil fluorescein dye drops into the eye or stain a fluorescein strip with saline.
• Ask the patient to blink to spread the dye.

Observe the area of injury with cobalt blue filter and notice if the area has a waterfall appearance of black fluid oozing from the defect which is the aqueous leaking from the anterior chamber.

Fig.7 Image by David Callanan, originally published in the Retina Image Bank.

Red flag signs - Deep lid laceration, subconjunctival haemorrhage, tear drop pupil indicating open globe injury, hyphaema indicating significant injury, sudden onset diplopia.7

Learning bite

Chemical burns, retrobulbar haemorrhage and open globe injuries including IOFBs should be assessed with urgency as it can lead to permanent vision impairment.7

Plain x-ray- AP and lateral views are helpful to evaluate the orbit and to assess fracture. It may help to rule out foreign bodies.

CT - first choice in assessing orbital trauma and orbital fractures as well as for detecting IOFBs. 1.5 to 2mm cuts are recommended in axial and coronal views.7

Fig.8 CT SCAN of orbital blow-out fracture via Radiopaedia

Ultrasound - useful if suspecting retinal detachment, vitreous haemorrhage, retrobulbar haemorrhage, IOFB but contraindicated if suspecting open globe injury.

MRI will be useful in patients with non-magnetic foreign bodies. It is contraindicated in those with metallic implants or pacemakers. It is not commonly used and contraindicated in metallic FB.

Learning bite

A missed intraocular foreign body with ferrous component will lead to late vision loss due to siderosis.

Fig.9 Suspected Ocular Trauma6

Fig.10 Chemical Eye Exposure6

Thermal burns management - Corneal heat exposure will require topical anaesthetic and antibiotics treatment. Corneal scarring will require keratoplasty in future. Lid burns will require plastic surgery intervention.

Learning bite

The key to chemical injury is the three I’s - irrigate, irrigate, irrigate. Instil topical anaesthetic for comfort and cooperation.

Prognosis6,8

• The sequela of the trauma is what determines the prognosis of blunt eye trauma.
• Blunt ocular trauma of high velocity generally may lead to the worst visual prognosis.
• Absence of a red reflex and pupillary defect are other factors that may lead to a worse visual prognosis.
• Traumatic optic neuropathy also leads to poor visual outcome.
• The extent of the initial injury and the mechanism of injury helps to predict whether poor visual outcomes might be expected.

Pearls6,8

• To avoid extrusion of intraocular contents, refrain from any unnecessary manipulation of the globe (including measuring intraocular pressure).
• Associated bony or intracranial injury should be ruled out with appropriate imaging.
• Advice against performing Valsalva manoeuvres especially in cases of globe rupture or retrobulbar hematoma. This can be facilitated by providing analgesia and antiemetics.
• Do not use eye patches in any circumstance, always use a protective eye shield which is rigid.
• To prevent endophthalmitis, provide prophylactic antibiotics.
• Definitive measures can be administered by the Ophthalmologist, but do not delay lateral canthotomy in known cases of retrobulbar hematoma.
• Loose superficial foreign bodies should be attempted to be removed with adequate analgesia, if the equipment and expertise are available.
• Lateral canthotomy should be performed in the event of orbital compartment syndrome, ideally within 2 hours of presentation to avoid optic nerve ischaemia which will eventually lead to permanent loss of vision.
  • Anaesthetise the site using a 25-gauge needle and inject 1% lidocaine with epinephrine to the lateral canthus. The direction should be away from the globe.
  • With a hemostat, gently crimp the lateral corner of the inferior eyelid.
  • Make a 1-2cm incision at the landmark created by the hemostat using scissors or surgical blade. Start the incision from the lateral canthus extending laterally. Identify the lateral canthal tendon by blunt dissection.
  • Identify the inferior crus of the lateral canthal tendon and strum the tendon using scissors or surgical blade pointing it inferiorly. Cut the fibres of the tendon until complete laxity of the lower eyelid is achieved.
  • Recheck the intraocular pressure. If the pressure is still elevated, this procedure can be repeated on the superior crus of the lateral canthal tendon.

1. Chen H, Jhanji V, Agrawal R, Yan H. Editorial: Updates on Ocular Trauma. Front Med (Lausanne). 2022 Apr 28;9:906253.
2. Justin GA. MD. Birmingham Eye Trauma Terminology (BETT). EyeWiki, 2023.
3. Murdock N, Mahan M, Chou E. Benign Orbital Tumors. 2022 Aug 18. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–.
4. John F. Salmon; Kanski’s Clinical Ophthalmology, A systematic approach, ninth edition. 2019.
5. Shirzadfar H, Amirzadeh P. A comprehensive study on eye issues and modern developments in visual rehabilitation for people with impaired vision. Int J Biosen Bioelectron. 2019;5(2):48-54.
6. Khaw PT, Shah P, Elkington AR. Injury to the eye. BMJ. 2004 Jan 3;328(7430):36-8.
7. Knott L. Eye Injuries (Assessment, Treatment and Management). Patient, 2022.
8. Mohseni M, Blair K, Gurnani B, et al. Blunt Eye Trauma. [Updated 2023 Jun 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan-.
9. Patel D. Eye injuries: improving our practice. Community Eye Health. 2015;28(91):41-3.
10. Anderson JD, Foster A. Ocular trauma. Trop Doct. 1989 Jan;19(1):35-40.
11. Vergasova SS. Feldsher Akush. Emergency care in eye injuries. 1986 Mar;51(3):21-7.
12. Ellingham TR. The immediate care of eye injuries. Anaesthesia. 1976 Apr;31(3):433-8.
13. Pokhrel PK, Loftus SA. Ocular emergencies. Am Fam Physician. 2007 Sep 15;76(6):829-36. Erratum in: Am Fam Physician. 2008 Apr 1;77(7):920.
14. Hodge C, Lawless M. Ocular emergencies. Aust Fam Physician. 2008 Jul;37(7):506-9.
15. The College of Optometrists. Sub-conjunctival haemorrhage. 2021.
16. Wang D, Rizzuti A. Eye Trauma Imaging. 2022 Jun 27. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-.
17. Singh P, Tyagi M, et al. Ocular chemical injuries and their management. Oman J Ophthalmol. 2013 May;6(2):83-6.
18. Gwenhure T. Procedure for eye irrigation to treat ocular chemical injury. Nursing Times,116:2, 46-48, 2020.
19. Kubal WS. Imaging of orbital trauma. Radiographics. 2008 Oct;28(6):1729-39. doi: 10.1148/rg.286085523.
20. Kuhn F, Morris R, Witherspoon CD. Birmingham Eye Trauma Terminology (BETT): terminology and classification of mechanical eye injuries. Ophthalmol Clin North Am. 2002 Jun;15(2):139-43, v.
21. National Institute for Health and Care Excellence (NICE) | CKS | Corneal superficial injury. Last revised in June 2022.
22. Bashir M, et al. Trends in ocular injuries among major trauma patients in England and Wales from 2004 to 2021. Research Square, 2023. 10.21203/rs.3.rs-3634731/v1