Photosensitivity: Epidemiology, genetics, clinical manifestations, assessment, and management

Photosensitivity is a genetically determined trait that may be asymptomatic throughout life or manifest with epileptic seizures. Photosensitivity usually begins before the age of 20 years with a peak age at onset at around 12. Both natural and artificial light may trigger seizures. Precise investigation must be carried out by intermittent photic stimulation that can elicit a clearly defined EEG response; video-EEG samples are reported to illustrate the various determinants of response and the main factors altering the effectiveness of intermittent photic stimulation. Management of photosensitive epilepsy includes non-pharmacological (e.g. avoidance of the provocative stimuli and wearing appropriate tinted glass) and pharmacological treatment. This review focuses on the emerging aspects of photosensitivity, in particular, the new guidelines for intermittent photic stimulation and briefly addresses epidemiological (in non-epileptic and epileptic subjects), genetic, diagnostic, and therapeutic issues.