A PROSPECTIVE STUDY OF ISOLATED VISUAL LOSS AND NEUROLOGICAL CAUSES

Abstract

Introduction: Vision impairment can be a reason of severe disability for an individual. Evaluating patients with neuro-ophthalmic symptoms may sometimes seem to be a daunting task as visual deficits in such patients involve complex neuro-anatomic pathways. The vision can be affected from a myriad of local ophthalmologic conditions and those affecting the neural structures conveying visual information from retina to brain. Such neuro-ophthalmologic diseases can be due to damage at any location from optic disc, optic nerve, optic chiasm, optic tract to optic radiation and occipital cortex.
Materials and Methods: This was a prospective study conducted from August 2022 to July 2023. 96 patients met the criteria and were included in the study. All the patients were informed about the study and their consent was taken. Detailed history was taken regarding the mode of onset, progression of visual impairment and associated symptoms like pain. Clinical examination including fundus was carried out in all patients. Visual acuity was assessed by Rosenbaum’s pocket screener and visual fields by confrontation method at the bedside.
Results: Majority of the patients were in the category of 10-20 years’ age group (38 patients; 39.58%). There was only one patient above 50 yrs. of age indicating that visual impairment of neurological origin is predominantly a disease of younger age group. Most studies showed a female-to-male ratio of 3:2, while the present study showed almost equal distribution. Majority of the patients had acute visual loss (41.66%), while 35.41% had a chronic variety of visual impairment. The remaining patients had sudden visual loss (8.33%) and sub-acute visual loss (14.58%). Sudden visual loss was seen in 8 patients due to stroke and consisted of visual field defects, either hemianopia or altitudinal defect. All patients belonging to this group were above 40 years of age and did not have any recovery during followup.
Conclusion: The commonest cause of acute unilateral and bilateral visual loss was demyelinating optic neuropathy. Chronic visual loss can also be due to demyelinating optic neuropathy as seen in two patients. The patients with acute and sub-acute visual loss without any identifiable cause can be empirically treated with steroids if not contraindicated. 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 the follow-up period of the study. Stroke is the commonest cause of sudden visual
impairment.