Visual field defects in acute optic neuritis - Distribution of different types of defect pattern, assessed with threshold-related supraliminal perimetry, ensuring high spatial resolution

Purpose: To assess the pattern and the local spatial frequency distribution of visual field defects (VFDs) in eyes with clinically diagnosed optic neuritis (ON) and their currently unaffected fellow eyes, using threshold-related, slightly supraliminal perimetry, ensuring high spatial resolution. Methods: Records obtained with the Tübingen Automatic perimeter (TAP, Oculus Inc., Dudenhofen, Germany) and the Octopus 101 perimeter (Haag-Streit Inc, Koeniz, Switzerland), using a standardized grid of 191 static targets within the central 30° visual field, were analysed retrospectively. VFDs were assigned to 15 classes. Results: Visual fields (VF) from 99 patients (26 male and 73 female subjects, aged from 18 to 51 years) with clinically diagnosed, acute ON (52 right eyes, 48 left eyes affected, one bilateral involvement) were evaluated. Central scotomas were the most common finding in associated eyes, covering 41% of all VFDs in affected eyes. Nerve fibre bundle defects were found in 29% and paracentral scotomas in 14% of all VFDs. Fellow eyes were perimetrically normal in 65% of the clinically monocular ONs. Nerve fibre bundle defects were found in 21% and diffuse scotomas in 9% of the fellow eyes. Conclusions: Central scotomas and retinal nerve fibre bundle defects are the most common VFDs in acute ON. Small central and paracentral scotomas that most probably would have been missed by automated thresholding perimetry with its relatively coarse grid could be detected by threshold-related, slightly supraliminal strategy. Of the fellow eyes in clinically apparent monocular optic neuritis, 35% present with visual field defects.