Orbital and periorbital swelling secondary to acute sinusitis is relatively common. Distinguishing between preseptal and orbital involvement can be difficult based on clinical observations alone. A delay in diagnosis and appropriate treatment may result in serious complications including blindness. The literature is reviewed and simple guidelines suggested to manage such patients, including their initial assessment, investigations with particular reference to the indications and timing of CT scanning, antimicrobial therapy and the type of surgery. These guidelines have been approved across disciplines in our unit and trialled successfully for 2 years.