BACKGROUND Ocular causes are the commonest causes of visual loss in general population. 1 Though neurological causes of visual loss form a minor proportion, they are important to be recognised because many of them are potentially treatable if diagnosed and managed appropriately. 2,3 Hence, this study was taken up with the following objectives-1. to evaluate the various causes of visual impairment presenting to the Neurology clinic and 2. To determine the magnitude of the problems of chronic visual loss. MATERIALS AND METHODS This was a descriptive study performed over a period of 2 years (Jan 2004 to Oct 2006). 48 patients of either gender aged 18 yrs. and above who satisfied the inclusion and exclusion criteria were included in the study. RESULTS Majority of patients had acute visual loss, 20 patients (41.66%) followed by chronic visual loss (17 patients, 35.41%). In majority of patients (n= 27 patients, 56.25%), demyelinating optic neuropathy was found to be the cause. In majority of patients with chronic visual loss (n= 17 patients, 35.41%), the cause was not known. Patients who had demyelinating optic neuropathy received steroids and majority of them (n= 12) received 3 days of dexamethasone followed by 11 days of oral prednisolone. CONCLUSION The majority of patients with neurogenic vision loss had diseases of anterior visual pathway. Chronic visual loss with no defined cause was observed, but in 2 patients demyelinating optic neuropathy was seen. The patients with acute and subacute visual loss with and without any identifiable cause were empirically treated with steroids if not contraindicated otherwise. Intravenous methylprednisolone for 3 days followed by 11 days of oral prednisolone is the best mode of treatment for demyelinating optic neuropathy. Recurrence of optic neuropathy was not seen during follow-up. Patients with severe impairment of vision and late presentation had poor prognosis in this study.

Visual loss is a common presenting symptom in the Outpatient Departments of Neurology, Ophthalmology and General Medicine disciplines. The present prospective study aims at evaluating 48 patients with partial or total visual loss as the predominant or only presenting symptom and with no associated ocular problems like cataract, glaucoma or diabetic retinopathy. The neurological causes were identified, analysed and tabulated; 39% of patients were below 20 years of age and there was 3:2 ratio of female versus male prevalence. Nearly 66% had acute visual loss and 35% had chronic visual loss. Majority of patients (48%) had profound visual loss limited to finger counting; 6% had normal visual acuity associated with field defects. The visual evoked potentials were abnormal in all cases with acute and sub-acute presentation and in some patients with sudden or chronic presentation also. The VEP abnormalities consisted of prolonged P100 latencies, loss of amplitudes or poor wave morphology. Cranial CT scan was done in 36 patients and was abnormal in 83% patients. It showed intracranial tumours in 8% patients and infarcts in another 8% patients. Cranial MRI scan was done in 12 patients and was normal in 83% patients. The aetiological considerations and treatment protocols followed are discussed. The limitations of such study in the present setup are also highlighted.