A complaint of "tunnel vision" may indicate constriction of the visual field. This may be observed with enlargement of the blind spot and papilledema as a consequence of raised intracranial pressure or with a compressive optic neuropathy. The visual field enlarges the further away from the eye the visual target used to map the field is held, hence there is in fact "funnel vision." In nonorganic visual impairment, by contrast, the visual field stays the same size with more distant targets (tunnel vision).
A tunnel vision phenomenon has also been described as part of the aura of seizures of anteromedial temporal and occipitotemporal origin. A closing in of vision may be described as a feature of presyncope. Cross References