FRCA Notes

Eye Injury Under Anaesthesia

Resources

  • Eye injuries under anaesthesia are rare, but can have devastating complications if they do occur
  • Eye injuries are rare (<0.1%)
  • Corneal abrasion is the most common type of damage, accounting for >50% of ocular injuries
    • 1 in 25 will have small abrasions which are asymptomatic, even with preventative measures
    • 1 in 2,800 will have symptomatic corneal abrasion

  • Visual loss (1 in 60,000 - 125,000) is much less common, although the incidence is higher following spinal (1 in 3,300) or open cardiac (1 in 1,1000) surgery

  • Other eye injuries include:
    • Ptosis from pressure on the supra-orbital fissure
    • Swollen eye (chemosis) or eyelids e.g. from head-down positioning
    • Exacerbations of glaucoma

  • Corneal abrasions can occur under anaesthesia due to:
    • Direct trauma, be it anaesthetic or surgical
    • Contact lenses
    • Exposure keratopathy to dry, unclosed eyes
    • Chemical injury e.g. from sterilising solutions

Risk factors

  • Long duration of operation
  • Prone or lateral positioning
  • Head and neck surgery

Pathophysiology

  1. Reduced tear production and reduced tear-film stability
    • Consequent corneal epithelial drying thus exposes the cornea to direct trauma
    • The inner surface of the eyelid becomes adherent to the globe and may cause injury when the eye is re-opened

  2. Lagophthalmos due to GA-induced relaxation of orbicularis oculi and a failure of eye closure (60% of patients don't close their eyes naturally under GA)

Prevention

  • Instillation of ointment/gel/eye drops to moisten the eyes e.g. methylcellulose
  • Tape eyelids shut
  • Bio-occlusive dressings
  • Use of non-toxic antiseptics - only povidone iodine 10% is safe
  • Eye-pads for prone or steep Trendelenburg surgery

Clinical features

  • Pain
  • Red eye
  • Tearing
  • Gritty sensation
  • Blurred vision
  • Photophobia

Management

  • Fluorescein staining + slit-lamp examination to confirm the diagnosis

  • Lubricants/ointments
  • Topical antibiotics e.g. chloramphenicol
  • Eye patching / bandage lens
  • Analgesia e.g. topical tetracaine, NSAIDs

  • Arrange ophthalmology follow-up although typically no long-term visual disturbance

  • This is a rare albeit devastating complication
  • Male patients >50yrs old appear to be at highest risk
  • Mechanisms include:
    • Ischaemic optic neuropathy
    • Central retinal artery occlusion
    • Other mechanisms

Ischaemic optic neuropathy

  • Optic nerve ischaemia owing to reduced perfusion from arterial hypotension, venous congestion or raised IOP
  • More common in those with existing vascular disease e.g. DM, HTN, smoking and either anaemia or polycythaemia
  • Perioperative contributions include prone positioning and surgery with major blood loss e.g. spinal surgery, cardiothoracics

Central retinal artery occlusion

  • Occlusion of the central retinal artery decreases blood supply to the entire retina
  • May be caused by direct pressure on the globe such as that arising from improper positioning, external pressure, intra-orbital pressure (e.g. retrobulbar haemorrhage)
  • May be an embolic phenomenon from the carotid artery (e.g. CEA) or heart (e.g. AF, CPB)

Other mechanisms

  • Cortical blindness
  • Glycine toxicity e.g. following TURP
  • Expansion of intra-ocular SF6 vitrectomy bubble due to use of nitrous oxide

This page has been peer-reviewed by Mr. James Richardson-May BMBS FRCOphth