Indirect optic nerve injury in two-wheeler riders in northeast India.
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.
Bhattacharjee
Harsha
H
Sri Sankaradeva Nethralaya, Beltola, Guwahati, Assam, India. ssnghy1@sify.com
Bhattacharjee
Kasturi
K
Jain
Lokesh
L
Sarma
Gitumoni
G
Sarma
Angshuman Sen
AS
Medhi
Jnanankar
J
Das
Dipankar
D
Buragohain
Sanjoy Kr
SK
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
D005938:Glucocorticoids; D008775:Methylprednisolone