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Visual outcome in optic nerve injury patients without initial light perception
1Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, India.
Purpose:
To assess the prognosis for recovery of vision in patients with blindness due to head injury, and to analyse the predictive value of visual evoked potential (VEP).
Methods:
One hundred consecutive patients with unilateral/bilateral blindness as a result of minor head injury were studied with regard to their visual status, CT scan, MRI scan and serial VEPs. Steroids were given to those presenting within one month of injury, 5 patients among them received methyl prednisolone. Transethmoidal decompression was done in 6 patients.
Results:
Visual improvement was recorded in 23 patients. Initial VEP failed to reveal any wave in 29 patients and was abnormal in 71. All the 14 patients in whom VEPs were repeatedly normal, irrespective of initial VEP status, showed varying degrees of visual improvement and none of the 15 patients with persistently negative VEPs showed visual improvement.
Conclusion:
Recovery of VEP from no response to abnormal wave or abnormal wave to normal VEP were indicators of relatively good visual prognosis. Overall, 23 patients showed visual improvement, but did not return to normal. Mode of injury, CT findings and timing of surgery did not influence the outcome.