Many authors have advocated early surgical intervention to avoid muscle degeneration in patients with blowout fractures with evidence of extraocular muscle entrapment imaged under computed tomography. However, there is still no golden standard with regard to the target timing of operations for releasing extraocular muscle. Between January 2002 and December 2011, the authors treated eight cases of blowout fracture with extraocular muscle entrapment. Notes from presumed cases of blowout fracture were retrospectively reviewed for information relating to surgical treatment and prognosis. In this series, a patient who was operated on 7 hours after injury showed the quickest recovery from diplopia. In contrast, a patient who was operated on 18 days after injury showed persistent diplopia for 2 years. Nevertheless, in patients who were operated on 3-11 days after injury, there was no obvious correlation between the outcome and the number of days between injury and the operation. It is concluded that, when emergency surgical intervention within several hours is not possible, it should be performed as soon after the injury as possible in order to prevent the increase of predictive fibrosis around the extraocular muscle.