Predictive value of computed tomography in visual outcome in indirect traumatic optic neuropathy complicated with periorbital facial bone fracture.

The visual outcome of 39 patients who had unilateral indirect type traumatic optic neuropathy and periorbital facial bone fracture treated at the Chang Gung Memorial Hospital in Kaohsiung between June 1996 and June 2001 was retrospectively evaluated, based on the results of computed tomography studies that grouped the associated fractures as anterior orbital fracture, posterior orbital fracture, orbital blow-in or blow-out fracture. Pretreatment and posttreatment visual acuities were obtained from the medical records and measurements of visual improvement degree and percentage were calculated after converting the visual acuities into log of the minimum angle of resolution (log MAR) units. This study reveals that posterior orbital fracture is associated with a worse prognosis in visual outcome than anterior orbital fracture, with visual improvement degree and percentage being 0.86 +/- 0.17 log MAR and 34.2 +/- 1.7% versus 1.56 +/- 0.27 log MAR and 58.9 +/- 1.7%, respectively (P = 0.02 and 0.004). Blow-in fractures such as an impacted lateral orbital wall did not predict significant deterioration in visual outcome. In addition, orbital floor or medial wall blow-out fractures did not predict significant improvement in visual outcome.