title: Indirect optic nerve injury in two-wheeler riders in northeast India.
abstract: OBJECTIVE
  To investigate the association of posterior indirect traumatic optic neuropathy and superior temporal orbital rim injury in two-wheeler riders and documentation of the clinical profile of such cases.
  
  
  METHODS
  Retrospective observational study.
  
  
  METHODS
  Records of all patients reporting with cranio-orbital injury and vision loss following road traffic accidents between October 1994 and April 2006 were reviewed and from them cases with vision loss solely from indirect optic nerve injury were taken up for study. The prognostic significance of different presenting features, role of intravenous methyl prednisolone (IVMP) and relative risk of superior orbital rim injury to posterior indirect traumatic optic neuropathy (at 95% confidence interval) was calculated.
  
  
  RESULTS
  Out of 129 consecutive cases of cranio-orbital injury, 35 had posterior indirect traumatic optic neuropathy with minor ipsilateral superior temporal orbital rim trauma and none used any protective headwear. Presenting clinical features like relative afferent pupillary defect ( P = 0.365), optic disc status ( P = 0.518) and visual evoked potential (VEP) ( P = 0.366) were disproportionate to visual loss. Only VEP had prognostic significance. The IVMP did not provide any added therapeutic benefit. The remaining 94 cases sustained direct blinding ocular trauma and 28 of them had associated intracranial pathology. The relative risk of superior temporal orbital rim injury to posterior indirect optic nerve trauma was 2.25.
  
  
  CONCLUSIONS
  Superior temporal orbital rim injury, even when minor, carries a potential risk for development of blindness from indirect posterior indirect traumatic optic neuropathy in two-wheeler drivers. Presenting signs do not correlate with visual status. Only VEP has prognostic significance and the condition is untreatable.
authors.affiliation: Sri Sankaradeva Nethralaya, Beltola, Guwahati, Assam, India. ssnghy1@sify.com
authors.forename: Harsha
authors.initials: H
authors.lastname: Bhattacharjee
authors.forename: Kasturi
authors.initials: K
authors.lastname: Bhattacharjee
authors.forename: Lokesh
authors.initials: L
authors.lastname: Jain
authors.forename: Gitumoni
authors.initials: G
authors.lastname: Sarma
authors.forename: Angshuman Sen
authors.initials: AS
authors.lastname: Sarma
authors.forename: Jnanankar
authors.initials: J
authors.lastname: Medhi
authors.forename: Dipankar
authors.initials: D
authors.lastname: Das
authors.forename: Sanjoy Kr
authors.initials: SK
authors.lastname: Buragohain
mesh_terms: D000063:Accidents, Traffic; D000293:Adolescent; D000328:Adult; D001642:Bicycling / Q000293:injuries*; D002648:Child; D005074:Evoked Potentials, Visual; D005260:Female; D005938:Glucocorticoids / Q000008:administration & dosage; D016489:Head Injuries, Closed / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D006260:Head Protective Devices; D006801:Humans; D007194:India / Q000453:epidemiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008775:Methylprednisolone / Q000008:administration & dosage; D008875:Middle Aged; D013508:Ophthalmologic Surgical Procedures; D020221:Optic Nerve Injuries / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D009915:Orbit / Q000293:injuries*; D012189:Retrospective Studies; D012307:Risk Factors; D014786:Vision Disorders / Q000175:diagnosis / Q000209:etiology* / Q000628:therapy; D014792:Visual Acuity / Q000502:physiology
chemical_list: D005938:Glucocorticoids; D008775:Methylprednisolone