Traumatic Optic Neuropathy - A Clincal Spectrum

Kowsalya Akkayasamy

Aim: To study the clinical profile of patients with traumatic optic neuropathy, mode of injury and response to treatment.

Materials & Methods: A retrospective study of 162 patients, between the period of 1/10/2009 to 15/9/2010 [ 1year], who attended a tertiary eye care institute in south tamilnadu , India, with a history of injury & defective vision was conducted. All patients underwent general examination to rule out any scar due to injury. Complete Ophthalmoscopic examination was done which included estimation of visual acuity by Snellens Chart,, retinoscopy & refraction, Diffuse illumination ,Slit lamp examination to rule out relative afferent pupillary defect, examination of colour vision by ishiharas pseudoisochromatic plates, central filed examination by Humphrey automated perimetry, fundus examination by direct ophthalmoscope, 90D & indirect ophthalmoscope was done. All patients underwent neuro imaging of brain either Computed axial tomography or Magnetic Resonance Imaging. Patients who presented within 2 weeks of injury were treated with injection methyl predinsolone and others were treated with multivitamins .

Results: Patients were divided into 4 categories according to age distribution. 1st age group comprises patients less then 20years, 2nd group- 20-40years, 3rd group -40-60years, 4th group above 60years. 14.81% belonged to first group, 51.85% to 2nd group which is the highest, 29.63% to 3rd group, 3.7% to fourth group. Relative afferent pupillary defect was present in all patients in the affected eye which account for 100%. History of loss of consciousness after injury was present in 51.23% of cases. A detailed study of mode of injury revealed that,1 51 patients out of 162 met with road traffic accident and suffered traumatic optic neuropathy , only 11 patients sustained injury from other modes like fall on stone or accidental injury by stick. Out of 151 patients 139 patients were two wheeler riders, 10 patients (6.17%) while travelling in 4wheeler (car/van/lorry), 2 patients (1.23%)in autorickshaw, other included 6.19%. Out of 162 patients, 24patients (14.81%) were students, 7.41% were drivers, others included 126 (77.78%).According to the complaints of patients while attending the hospital, 1.85% had defective vision in both eyes, 46.30% had left eye defective vision 51.85% had right eye defective vision. Based on visual acuity, patients were classified into 3rd groups i.e.6/6-6/60, 6/60-PL+, NOPL. 31.52% of eyes (affected eye) fell in 1st group, 49.09% fell in 2nd group, 19.39% had No perception of light.Colour vision estimation of the affected eyes, showed defective colour vision in 87.27% and 12.73% had normal colour vision. Central fields by Humphrey field analysis revealed normal fields in 20.99%, peripheral constriction in 15.76%, superior filed defect in 9.09%, inferior field defect in 3.03%, temporal field defect in 8.48%, nasal field defect in 0.61% and fields examination was not possible due to poor vision in 42.4%.The other eye was normal in 91.19% 0.63% had superior heminopia, 0.63% had temporal hemianopia and1.26% had tubular field. Fundus examination showed Normal optic disc in 14.55% of case, pale optic disc in 60%, Segmental pallor of disc in 23.64%, Hyperemic disc in 1.21% and Pallid edema in 0.61%. In general examination 20.99% had scar in forehead, 21.6% had scar in lateral 1/3rd of eye brow. Neuro imaging of brain and orbit showed fracture frontal bone, orbital walls more commonly. 23.46%of patients (within 2 weeks of injury) received Inj.Methyl Prednisolone 1gram per day for 3 days followed by oral steroids. 76.54% patients received muti vitamins. 1month review revealed vision improvement in 1% of patients in first group and none in second group.

Conclusion: Traumatic optic neuropathy is more common in two wheeler riders and any treatment modality is not beneficial to the patient in terms of visual recovery.