Eye Injuries: Pathophysiology, Assessment and Treatment
Updated: 19 hours ago
The eye is a small, delicate, and highly specialised organ, and one that is disproportionately vulnerable to trauma given its exposed position on the face. Ocular injuries range from minor abrasions to sight-threatening rupture, and while they account for a relatively small portion of overall trauma presentations, they carry an outsized risk of permanent disability. Eye injuries occur across a broad spectrum of mechanisms: blunt trauma from a ball, fist, or airbag; penetrating injury from glass or projectiles; chemical exposure from industrial or household substances; and radiation or thermal injury. This article explores the pathophysiology underlying different categories of eye injury, before turning to assessment and evidence-based treatment approaches.
Pathophysiology
Blunt Trauma
Blunt forces to the globe compress the eye along its anterior-posterior axis while causing sudden equatorial expansion, a mechanism known as coup-contrecoup. This can result in hyphaema (bleeding into the anterior chamber), lens dislocation, retinal detachment, and in severe cases, globe rupture (a full-thickness breach of the eye's outer wall, the cornea and/or sclera). The sudden pressure spike can also cause orbital "blow-out" fractures, where the thin orbital floor gives way, potentially entrapping the inferior rectus muscle and surrounding fat.
Penetrating and Open Globe Injury
Sharp objects or high-velocity fragments can breach the corneal or scleral wall, producing an open globe injury. This is a true ocular emergency: loss of the eye's structural integrity allows intraocular contents to prolapse outward, intraocular pressure to collapse, and pathogens direct access to the vitreous, carrying a high risk of endophthalmitis (intraocular infection) if not addressed promptly. Retained foreign bodies add the potential for chemical toxicity (e.g. copper or iron-containing fragments), on top of the mechanical and infective risk.
Chemical Injury
Chemical burns to the eyes are classified by pH. Alkali substances (e.g. cement, drain cleaners, ammonia) are generally more destructive than acids, as they cause liquefaction necrosis, breaking down cell membranes and lipids, allowing the substance to penetrate deeply and rapidly through the cornea into the anterior chamber. Acids, by contrast, tend to cause coagulative necrosis, which denatures surface proteins and forms a barrier limiting further penetration. Both processes can damage the corneal epithelium, stroma, and limbal stem cells, the last of which are critical for corneal healing and regeneration.
Thermal and Radiation Injury
Thermal injury (e.g. flame, hot liquid) typically affects the eyelids and ocular surface, with the natural blink reflex often protecting the cornea itself. Radiation injury, including UV keratitis ("welder's flash" or snow blindness), damages the corneal epithelium through direct cellular injury, presenting with delayed but often severe pain as epithelial cells slough some hours after exposure.
Assessment and Treatment
History and Red Flags
Mechanism of injury guides the direction of examination. High-velocity fragments (grinding, hammering, lawn mowing) raise suspicion for penetrating injury and intraocular foreign body, while direct blows raise suspicion for blunt globe injury and orbital fracture. Key red flags on history include sudden vision loss, a curtain-like visual field defect (suggesting retinal detachment), severe pain, photophobia, and a history of chemical exposure.
Examination
When an open globe or rupture is suspected, examination should be gentle and non-invasive, no pressure on the eye, no attempt to evert the lid or check intraocular pressure. Where the globe is entirely intact, a structured exam includes:
• Visual acuity: the single most important baseline measurement, taken before any other manipulation
• Pupils: shape, symmetry, and reactivity (an irregular or peaked pupil suggests globe rupture)
• Anterior segment: checking for hyphaema, foreign bodies, corneal opacity or laceration
• Extraocular movements: restricted movement (particularly upward gaze) may indicate muscle entrapment from an orbital fracture
• Fluorescein staining: used to highlight corneal abrasions or the "Seidel sign" (aqueous leakage) in suspected open globe injury
In practice: a patient presents after being hit in the eye with a squash ball, with blurred vision and pain. Checking visual acuity first, before any other examination, is what separates a straightforward assessment from a missed globe injury.
Treatment Principles
• Suspected open globe/rupture: rigid eye shield (never a pressure patch), analgesia, antiemetics (vomiting raises intraocular pressure and risks extruding contents), nil by mouth, urgent ophthalmology referral/notification, do not give eyedrops or attempt further physical examination
• Chemical injury: immediate and copious irrigation is the priority before any other assessment, ideally for a minimum of 15 to 30 minutes. Alkali burns require particularly prolonged irrigation given their capacity for deep penetration
• Corneal foreign body/abrasion: removal of superficial foreign bodies if visible and accessible, topical antibiotics, and analgesia
• Orbital blow-out fracture: analgesia, avoidance of nose-blowing (risk of orbital emphysema), and hospital referral/notification. Surgical repair is indicated if there is significant entrapment or enophthalmos
Even minor-looking trauma can conceal sight-threatening pathology.
Conclusion
Eye injuries span a wide spectrum of severity, but the stakes are consistently high, even minor-looking trauma can conceal sight-threatening pathology, and delayed recognition of red flags risks permanent vision loss. Blunt, penetrating, chemical, and thermal mechanisms each carry distinct patterns of damage, but the priority is always the same: identify globe-threatening features early, avoid interventions that could worsen an open globe, and escalate promptly to ophthalmology when in doubt.
References
Queensland Ambulance Service. Clinical Practice Guidelines: Trauma/Eye injury. https://www.ambulance.qld.gov.au/__data/assets/pdf_file/0024/219138/cpg_eye-injury.pdf
EMS Management of Eye Injuries. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK585131/
Blunt Eye Trauma. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK470379/
Ocular Burns. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK459221/
Hyphema. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK507802/
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Disclaimer: This article is general education for students. It is not medical advice, and it does not replace your service's clinical practice guidelines, your educators or your local protocols.
