The literature and data on photic- and pattern-induced seizures were reviewed and a consensus was developed of risk factors for visually evoked seizures, at a workshop of the Epilepsy Foundation of America, in Alexandria, VA, August 2004. Photosensitive individuals are at risk of seizures from flickering or intermittent images and certain patterns encountered in television, video games, computer screens, motion pictures, advertising displays, rock concerts, theater, opera, dance halls, nightclubs, and architectural materials. To reduce the risk of provoking seizures, the following recommendations were made for the design of flashing images or regular patterns: Potential hazards to be avoided include 1) a flash of luminance >20 cd/m2, at a frequency >3 Hz, in 25% of screen area at viewing distance; 2) a transition to and from saturated red; 3) a striped pattern, with more than 5 light-dark pairs of stripes; 4) stripes that change direction, oscillate, flash, or reverse in contrast; and 5) a pattern of >8 pairs of stripes that is unchanging or drifting in one direction. [1]
COMMENT. Visually induced seizures may be generalized or focal, idiopathic or symptomatic, or represent a pure, reflex photosensitive epilepsy (Ped Neur Briefs Jan 2004; 18:7) [2]. For further articles on photosensitive seizures, see Ped Neur Briefs 2004;18:36-37.
The background information obtained from a review of the literature and used by the EFA for their consensus recommendations is outlined by [3].
Reflex seizures in children with malformations of cortical development tend to be refractory to anticonvulsant medications but may respond to surgical resection of focal lesions. [4]