Background To compare clinical findings of orbital trapdoor fractures between adult and paediatric patients.

Methods Paediatric patients were categorised into two groups by age: children (0–9 years) and adolescents (10–19 years). Adult patients were categorised into two groups by age: early (20–44 years) and middle-late adulthood (≥45 years). Demographic data, ocular and periocular complications, CT findings and binocular single vision field (BSVF) were compared among age groups.

Results This study included 105 patients (105 sides, 22 children, 59 adolescents, 14 patients in early adulthood and 10 patients in middle-late adulthood). In patients with fractures of the orbital floor and medial wall, both walls presented as trapdoor fractures in paediatric patients, while one wall presented as a non-trapdoor fracture in adult patients (p=0.061). None of the adult patients showed extraocular muscle incarceration, whereas this was present in 8 of 22 children (36.4%) and 7 of 59 adolescents (11.9%) (p=0.005). Hypoesthesia of the infraorbital nerve more frequently occurred in adults (p=0.004). As the preoperative BSVF was larger in adult than in paediatric patients (p=0.007), the percentage of adult patients who underwent surgical reduction of orbital fractures tended to be lower (p=0.058). Postoperative change in BSVF was smaller in adult patients (p=0.005).

Conclusions Fracture pattern, type of incarcerated tissue and incidence of hypoesthesia of the infraorbital nerve were different between adult and paediatric patients. Adult patients had a larger preoperative BSVF and less need for surgical reduction; however, there was less improvement in postoperative BSVF.