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Ophthalmic Trauma

Introduction

 

Ocular trauma is a common presentation not only to ophthalmology units, but also in Accident and Emergency, and primary care settings. Nationally, the incidence of ocular trauma is so common and diversified that it is hard to keep a true statistical record. However, the American Society of Ocular Trauma (ASOT) has reported that the number of traumatic eye cases were more than 2.5 million each year in the United States.

 

Despite the recent promotion of safety regulations, its incidence remains high. With eye trauma being a serious threat to vision, it is important that we familiarize ourselves to this presentation.

 

Presentation

 

The most obvious presentation is a red eye, pain, and a decline in vision. However, it can also be visually symptomless and painless. This is typically true for tiny foreign projectiles, or an intraocular foreign body (IOFB). IOFB is often painless as there are no nerve endings in the retina and vitreous humour. Therefore, a high index of suspicion is required, and a referral to an ophthalmologist must be prompt if there is posterior segment involvement. And ideally, these patients are best not prescribed any ointment unless paramount as it interferes with the ability to carry out a thorough examination of the posterior segment by an ophthalmologist.

 

Aetiology

 

Trauma to the eyes can happen in weird and wonderful ways. More common causes originate from the workplace, household implements, sports, combat, and road traffic accidents. A few examples are metals, BB guns, wood (endophthalmitis should be ruled out), plastic, iron (siderosis bulbi), copper (chalosis), and fireworks.

Classification of Ocular Trauma

 

By enlarge, ocular trauma can be classified as:

  • Eyelid trauma
  • Orbital fractures
  • Trauma to the globe
  • Chemical injuries

 

    Subsequent management depends on the nature and extent of the trauma. It is recognised as either an emergency, urgent, or semi-urgent. Emergency cases must be treated in minutes, otherwise they may be irreparable. Classically these include chemical burns of the conjunctiva and cornea. Urgent cases must be dealt with in hours. To name a few, these include penetrating injury, corneal abrasions, deep eyelid lacerations, radiant energy burns and traumatic optic neuropathy. An orbital fracture falls under the semi-urgent category which must be managed within 1-2 days.

     

    Eyelid Trauma

     

    PERIOCULAR HAEMATOMA

    This is the famous 'black eye'. It is a collection of hematoma and oedema around the orbit, most commonly due to blunt trauma. Eyelid trauma is by enlarge harmless, however, certain serious complications should be ruled out:

    • Trauma to the globe
    • Orbital roof fracture, suspicious if subconjunctival haemorrhage is present without a visible posterior limit
    • Basal skull fracture which may give rise to characteristic bilateral ring haematomas

     

      LID LACERATIONS

       

      With this, the importance lies not only on the cosmetic effect, but on the tearing system. Careful exploration is paramount to ensuring the integrity of the canalicular system. Otherwise this will pose a future problem of 'wet' eye.

       

      With any injury, the patient’s tetanus immunisation status is crucial. Although unlikely, if the patient had not had prior tetanus immunisation or no booster shots within the last 10 years, it is advisable to commence 250 units of human tetanus immunoglobulin IM or IM/subcut tetanus toxoid respectively.

      Orbital fractures

       

      Orbital fractures are categorised anatomically into floor, medial, roof, and lateral fractures (in the order of frequency). A blow-out floor fracture is typically caused by a sudden increase in orbital pressure due to an object larger than the orbital aperture (about 5 cm). Blow-out medial fractures typically occur concurrently with orbital floor fractures. Isolated cases are rare, unlike roof fractures. Lateral wall fractures are the least common as the bones on the lateral aspect are the strongest. Typically it is associated with great facial trauma. For any orbital fractures, it is important to exclude CSF leak, which promotes a risk of meningitis.

      • Periocular signs
      • Infraorbital nerve anaesthesia
      • Diplopia – Hess test is useful here
      • Enophthalmos and ocular damage as late complications

       

        Image: Orbital Fractures Medial Wall and Floor

        Trauma to the Globe

         

        The terminology chosen here is consistent with the Birmingham Eye Trauma Terminology (BETTS) adopted by ASOT.

        • US may be useful in the event of IOFB, suprachoroidal haemorrhage, and retinal detachment. However extra caution must be paid in the presence of globe rupture.
        • Plain radiograph is often arranged if IOFB is suspected
        • CT is however superior as it adds value in determining the integrity of facial, intracranial, and intraocular structures.
        • MRI is useful for assessment of the globe
        • Electrodiagnostic testing is used to assess the optic nerve and retina, particularly if the original injury was some time ago, and there is a suspicion of IOFB

         

          Image: BETTS Terminology and Globe Rupture

          Chemical Injuries

           

          Chemical injuries are the only eye trauma that requires emergency attention without engaging in the conventional history taking approach. The majority of these cases are accidental and a few are due to assaults. It is more common in the workplace and as alkalis are more widely used commercially and domestically, it is not surprising that alkali burns are twice as frequent as acid burns. Examples of alkalis are lime, ammonia, and sodium hydroxide. Acids include sulphurous, sulphuric, acetic, chromic, hydrofluoric, and hydrochloric acids.

           

          • Copious irrigation – sterile balanced buffer solution, such as normal saline or Ringer lactate solution for 15-30 minutes; topical anaesthesia administration is advisable as it ensures patient comfort during irrigation
          • Double eversion of the eyelids – to identify any foreign particulate
          • Debridement – promotion of re-epithelialisation besides removing any chemical residue
          • Admission – 3 or 4 days for serious cases to ensure drop instillation in the early phase as this promotes healing

           

            Image: Corneal Grading and Chemical Injury

            References

            1. Oxford Handbook of Ophthalmology 2nd Edition
            2. Oxford Specialty Training: Training in Ophthalmology 
            3. The Massachusetts Eye and Ear Infirmary: Illustrated Manual of Ophthalmology
            4. Clinical Ophthalmology: A Systematic Approach, Jack J. Kanski

             

            IMAGES

            All images taken from Clinical Ophthalmology: A Systematic Approach, Jack J. Kanski

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