Acute orbital compartment syndrome is a potentially treatable cause of vision loss. Our prospective, national study sought to quantify the annual incidence of emergency lateral canthotomy and cantholysis (ELCC) & establish the presentation, aetiology and outcome following ELCC.

All UK consultant and associate specialist ophthalmologists were asked to report patients who had an ELCC performed over a 12 month period from April 2016 until March 2017. Cases were collected using the established British Ophthalmological Surveillance Unit reporting system Further demographic & clinical data were collected via questionnaire including one year follow up data.

53 confirmed cases were reported giving a UK population incidence of approximately 0.8 per million. Trauma was the most common antecedent (64%). Other causes included elective surgery, infection, neoplasm, orbital steroid injections & anticoagulation. Presenting signs included pain (29%), proptosis (32%), vision loss (32%) and raised intraocular pressure (36%). Only 26% of cases had an RAPD recorded. Surprisingly, CT imaging was performed in 50% of patients prior to ELCC – only 30% were treated within 2 hours of symptom onset. Outcomes suggest that 48% of patients gained at least one line of vision within one week of undergoing ELCC, with 60% of patients demonstrating visual improvement at last follow-up.

This study establishes a robust estimated population incidence for orbital compartment syndrome treated by emergency canthotomy and cantholysis. Although treatment can be rapid, for many patients there is a significant delay. This may, in part, be due to the reliance on imaging for what should be a clinical diagnosis.