Abstracts

Rationale: Among the 50 million individuals afflicted with epilepsy worldwide, 5% suffer with photosensitive epilepsy, characterized by the presence of an abnormal brain signal response - a 'photoparoxysmal response' (PPR) - to photic stimulation. The influence of visual stimuli to provoke seizures has long been recognized, yet little has been done to apply this knowledge toward finding methods with which to prevent photic-triggered seizures. Due to our current lifestyles, photosensitive individuals are at risk because of the ubiquity of artificial lighting in our everyday lives, including photic stimulation from TV, video games, computers, portable electronic devices, and fluorescent lighting. Further, despite a century of development, the newest medications are no more effective than the first agents, and one third of patients fail medication altogether. A non-pharmacological approach is therefore desperately required to mitigate the fear, burden, and physical harm that often accompany this disorder. A systematic review of the literature and a case report are presented here, whereby we manipulated specific wavelengths of light using specialized optical lenses, proving a promising, simple, and non-pharmacological approach to the treatment of photosensitive epilepsy.  Methods: We tested whether specific tints of lenses in colored glasses can reduce the incidence of PPR during an electroencephalogram (EEG) with photic stimulation in an 18-year-old female patient with photosensitive epilepsy at the Winnipeg Health Sciences Centre in Canada. We tested 13 pairs of glasses with specialized optic technology that incorporate unique dyes formulated to manipulate light by absorbing specific wavelengths.  Results: The EEG results demonstrated that, at a frequency of 12 Hz, a significant reduction in PPR occurred with 5 of the tints, including 3 tints that mitigated PPR completely. Specifically, after 50 seconds of photic stimulation, no discharge was seen in the dark grey, grey-brown, and gold mirror-colored lenses, with approximate light wavelength mitigation of 400-700 nm in each of these tints.  Conclusions: Specialized lenses that mitigate specific wavelengths of light hold tremendous potential to inhibit seizures in individuals with photosensitive epilepsy. The results of our experiment support previous research regarding optical filters to inhibit PPR, where the majority of patients derived benefit from the filters. Our study contributes to the literature by increasing the understanding of the role that optical filters play in treating photosensitivity, and by presenting novel future directions in research and innovative technologies which could render photosensitive patients essentially seizure-free, while reducing or eliminating the need for medications with harmful side-effects. Polarized lenses - demonstrating limited efficacy - and tinted lenses have been developed predominantly for outdoor use, however rather than deflecting the complete spectrum of light as in polarization, we plan to develop and test non-tinted contact lenses and glasses that are specially formulated to each individual with photosensitive epilepsy so as to absorb the specific wavelengths that are problematic to each unique patient. These glasses and contacts can be worn both indoors and outdoors, while simultaneously incorporating optical prescription, thereby providing relief in all environments without the undesirability of colored tints. Accomplishing these goals would lead to an innovative treatment directly benefitting the millions of photosensitive epilepsy sufferers worldwide.  Funding: No funding