Emergency lateral canthotomy and cantholysis for acute globe subluxation

Globe subluxation occurs when the equator of the globe protrudes anteriorly beyond the eyelid aperture, often leading to retraction of the eyelids behind the globe.^1–7 This results in orbicularis oculi muscle spasm, preventing eyelid closure and significantly restricting extraocular movements (EOM), making reduction of the globe more challenging. Additionally, traction on the optic nerve and retinal vasculature can contribute to visual impairment.^1,3,8–10 Patients with acute subluxation typically present with severe ocular pain and substantial vision loss.^1–14

Globe subluxation is traditionally categorised into three types: spontaneous, voluntary and traumatic. The term “spontaneous” is somewhat misleading, as most reported cases involve an external triggering factor, such as forceful eye rubbing, contact lens placement or friction against a pillowcase during sleep.^1,2,5–14 Voluntary subluxation occurs with conscious effort, whereas traumatic subluxation results from an identifiable external force.⁵

The exact pathogenesis of spontaneous globe subluxation remains unclear. However, several predisposing factors have been identified, including thyroid eye disease, floppy eyelid syndrome, orbital fat hypertrophy in obese individuals, space-occupying retrobulbar lesions and malar hypoplasia.^1,2,7–14

Management of globe subluxation primarily involves manual reduction of the globe back into the orbit.^1,3,5 When manual reduction is unsuccessful, alternative interventions such as orbital decompression, lid-shortening procedures and lateral tarsorrhaphy have been described as viable treatment options.^1,2,4,11

Case report

A 40-year-old woman presented to the emergency department (ED) after her left eye suddenly “popped out” following forceful eye rubbing (Figure 1 and 2). She reported immediate vision loss and severe ocular pain. There was no history of trauma, prior episodes of globe subluxation, thyroid eye disease, floppy eyelid syndrome or orbital tumours. Her medical history was significant for hypertension, and she had a body mass index (BMI) of 28kg/m². She was a former smoker and denied alcohol or drug use.

On examination, the left globe was completely displaced anteriorly, resting outside the orbit. The patient was unable to close her eyelids, and extraocular movements were completely restricted. Visual acuity in the affected eye was limited to hand movements, with a relative afferent pupillary defect (RAPD). Intraocular pressure (IOP), measured with an iCare tonometer, was 39mmHg in the left eye. Examination of the right eye was unremarkable, with a visual acuity of 6/6, full extraocular movements, a normal pupillary reflex and no evidence of proptosis.

Given a suspected presentation of retrobulbar haemorrhage, the ophthalmology team was consulted remotely and advised an urgent lateral canthotomy and cantholysis. The ED team began the procedure and was only partly completed when the attending ophthalmologist arrived. Examination suggested the presentation was more fitting with globe subluxation. Attempts of manual reduction failed, and a lateral canthotomy with both inferior and superior cantholysis was done. Within minutes, the proptosis resolved and the globe spontaneously returned to its normal position (Figure 3 and 4).

Post-reduction assessment showed an improvement in visual acuity to 6/15, with a stable IOP of 22mmHg. A non-contrast computed tomography (CT) scan of the orbits revealed no intracranial or intraorbital abnormalities, fractures or other structural pathology. Expected post-procedural subcutaneous gas was noted in the periorbita.

The patient was admitted for observation, with chloramphenicol ointment applied to the canthotomy wound site. At the 24-hour follow-up, visual acuity had improved to 6/12, with full extraocular movements, equal and reactive pupils and an unremarkable slit-lamp examination. A final follow-up at 3 weeks demonstrated further improvement, with a visual acuity of 6/9, full extraocular movements, intact optic nerve function, resolved RAPD and adequate wound healing. Surgical revision of the lateral canthotomy was not required, and the patient was discharged with an excellent prognosis.

View Figure 1–4.

Discussion

Timely repositioning of the globe is crucial in minimising the risk of optic nerve and retinal vasculature complications.^3,8–10 Subluxation-induced optic neuropathy has been reported as a potential consequence,^9,10 highlighting the importance of prompt intervention.

Following the release of the lateral canthal ligaments, the globe can often be repositioned with minimal resistance.^12,15 However, despite successful reduction, one should remain vigilant for potential complications, including anterior segment ischaemia, phthisis bulbi and neovascular glaucoma.¹² Appropriate follow-up should be arranged to monitor for these complications and ensure optimal recovery.

While effective, this procedure is not without risk. Potential complications include iatrogenic globe rupture, infection, bleeding, injury to surrounding structures and loss of lower-lid suspension with subsequent eyelid malposition.¹⁵ Competence in the technique and a sound understanding of orbital anatomy are therefore essential to maximise safety and efficacy.

Conclusion

To the best of our knowledge, this is the first report describing the use of lateral canthotomy and cantholysis as a primary treatment for spontaneous globe subluxation. This procedure is included in emergency medicine training, enabling trained emergency clinicians to perform it when an ophthalmologist is unavailable—particularly after-hours or in smaller regional centres. When performed competently and with awareness of orbital anatomy, it provides a rapid and effective means of globe reduction and is valuable when manual reduction has failed.