Abstract

Objective: Visual impairment is a common problem in tuberculous meningitis (TBM). Present study has been conducted to evaluate the prevalence of visual impairment at presentation and at 3 months.

Methods: Twenty seven consecutive HIV negative patients with TBM were included. Visual acuity, colour vision, field of vision, and visual evoked potentials (VEP) were recorded at baseline and at 3 months. The criteria for visual impairment were: visual acuity <6/12 and <N/10, defective color vision, and visual field abnormality either alone / in combination. Fundus was examined by a single examiner using slit lamp biomicroscopic examination with 90 D lens and by indirect ophthalmoscopy with 2.2D lens.

Results: Twelve patients out of 27 had visual impairment at presentation and the causes were optochiasmatic arachnoiditis (n=6), optic atrophy (n=2), occipital infarct (n=1) and unremarkable (n=3). Three patients showed improvement in visual acuity, 6 patients had no change and 3 patients expired at 3 months. On multivariate analysis papilloedema, optic atophy, temporal disc pallor and hydrocephalus were predictors of visual impairment at 3months (p< 0.001 ).

Conclusion: Visual impairment in TBM is observed in half the patients. It may be predicted by the presence of hydrocephalus on computerized tomography (CT)/ magnetic resonance imaging (MRI), while a simple bedside fundus examination can predict the visual impairment at three months. VEP helps in detecting sub-clinical visual impairment.

Keywords: Tuberculous meningitis; Opticatrophy; Optochiasmatic arachnoiditis; Visual impairment; Visual evoked potentials