[Managing unexplained visual loss--a "quick guide"].

Optic neuritis and anterior ischaemic optic neuropathy (AION) present with acute visual loss. AION shows a swollen optic disc, in optic neuritis it may be swollen in one third of the patients. Optic neuritis patients complain usually about pain with eye movements. A tumour causes slowly progressive visual loss, mostly painless. In all these cases a relative afferent pupillary defect (RAPD) may be expected. If RAPD is missing, a problem of the optic media (retinoscopy, pinhole test), macular disease (micropsy, improvement with grey filters), amblyopia or non-organic visual loss can be causative. However, it has to be considered that a homonymous visual field defect may be perceived as an unilateral visual loss. Therefore visual field testing is necessary.