This is a one year prospective study using the Scottish ophthalmic surveillance unit reporting system amongst Scottish ophthalmologists. Only patients residing within Scotland with a new diagnosis of orbital cellulitis between November 2011 and October 2012 were including in this study. The overall total response rate was 66.4%. In total there were 20 reported cases in the study period affecting six females and 14 males. Fifteen of the 20 cases (75%) were in-patients aged less than 15 years (paediatric group) and five cases (25%) occurred in patients over 17 years (adult group). Within the paediatric age-group, six children (40%) were less than five years old, three children (20%) were between five and 10 years old and six children (40%) were 11 to 15 years old. The overall minimum incidence of orbital cellulitis in Scotland was estimated at 1.6 per 100,000 population in children 0 to 15 years and 0.1 per 100,000 in adults. Seven of the 15 children (47%) had a preceding upper respiratory tract infection and sinus involvement was confirmed by CT scan in 13 of the 15 (87%) children. In comparison, no adult had a pre-existing reparatory infection; one adult was immuno compromised due to haematological malignancy and two adults had preceding trauma. One had preceding facial trauma and one had an intraorbital foreign body and endophthalmitis. The pathogens were isolated in 70% of the cases. Streptococci species and emopholus inferenzie were the most frequently isolated pathogens in children and polymicrobial infection was common. In comparison, single organisms were isolated in adults. All patients received intravenous antibiotics on admission, dual therapy with a third generation cephalosporin and Flucloxacillin were the most common empirical therapy in nine cases, followed by triple therapy with addition of metronidazole in four cases. One adult and a child were treated empirically with a co-amoxiclav monotherapy. Five patients received other dual or triple therapy with various antibiotic classes. All patients underwent CT-imaging. Twelve children (80%) and three adults (60%) had an abscess identified on CT-scanning. Within the paediatric group, five (33%) children had orbital abscesses, five (33%) had sub-periosteal abscesses (SPA) and two (13%) had both orbital and SPAs. Three adults had orbital abscesses only. All children with abscesses and two adults with abscesses underwent surgical intervention. One adult with an orbital abscess had no surgery and recovered with orbital antibiotics alone. Of those who were surgically drained, there was variation in the extent of drainage received; external drainage of abscess alone in seven patients (47%), sinus surgery alone in three patients (20%) and combined drainage of abscess and sinus surgery in four patients (27%). All children completely recovered with no serious adverse outcomes. In the adult group, one patient had intracranial spread of infection with cranial surgical input and the patient with preceding intraorbital trauma and ophthalmitis progressed to evisceration. At three months, three adults were discharged. Of the two remaining under care, one had undergone evisceration and the other had leukaemia with diffuse orbital and lacrimal infiltrate. The authors conclude that this is the largest series of orbital cellulitis reported from the UK. Orbital cellulitis occurs more commonly in children than adults; sinusitis is the major preceding factor in children and adults are more likely to have trauma and comorbidities. The current practice in Scotland is to surgically manage all paediatric SPAs and orbital abscesses, even in those less than nine years of age. Streptococcus species are the most common pathogens in children. Influenza appears to be emerging as a frequent pathogen. Respiratory track organisms are less predictable pathogens in adults, depending on preceding trauma and commodities.