Researchers have developed a liquid crystal lens that blocks triggering wavelengths of light without ruining the moviegoing experience.Scientists in Europe have developed a special eyeglass lens that could make movies, TV, and video games safer for people with photosensitive epilepsy. Able to be toggled on and off, the technology's ability to filter triggering wavelengths of light holds promise as a relatively simple way to make media more accessible to people who otherwise might need to steer clear.We've come a long way since the 90s, when epilepsy-triggering light sequences were included in TV shows without warning. Today, many films, TV episodes, and games are preceded by splash screens warning viewers that certain scenes could induce seizures in people with photosensitive epilepsy, which is thought to impact 1 in 4,000 people and roughly 5% of those with epilepsy. But without knowing which specific scenes or aspects of gameplay could be triggering, many people with photosensitive epilepsy end up avoiding that media entirely.Nobody deserves a life without Star Wars, Stranger Things, or nearly every Spider-Man movie, however. To make potentially triggering media safer for those with photosensitive epilepsy, engineers, neuroscientists, and ophthalmologists at the University of Birmingham and the University of Glasgow have developed a thermal-controlled lens that filters light within the 660 to 720-nanometer wavelength range—the range most commonly associated with light-induced seizures.
The lenses themselves consist of cholesteric liquid crystals, or CLCs. Because CLCs are highly responsive to temperature changes and electric fields, they're used in anti-counterfeit labels, polarizing films, optical filters, color-changing cosmetics, and even healthcare diagnostics. Those same temperature and electric fluctuations can be leveraged to allow wavelength-blocking lenses to turn on and off. In a paper for Cell Reports Physical Science, the researchers write that their lenses are functionally similar to plain glass at room temperature, but block 98% of light within the epilepsy-triggering wavelength when they reach 36.5 degrees Celsius (97.7 degrees Fahrenheit).The researchers' prototype uses a negative temperature coefficient thermistor laid over the lens to monitor CLCs' temperature. An external controller adjusts the voltage delivered to the CLCs to make them warmer or allow them to cool down. This allows the lens wearer to toggle their glasses' accessibility feature on and off; when it's on, triggering wavelengths are filtered out, but when it's off, the lens functions like a regular glass or polycarbonate lens.The researchers would need to test their prototype with people who have photosensitive epilepsy before commercializing their product; they'd also need to find a less bulky method of controlling the CLCs' temperature. But a 98% wavelength blockage rate is impressive for an initial go-around. The researchers also note that should an epileptic person be sensitive to a different wavelength of light, the lens could be adjusted to respond to a different temperature. They even hope to integrate toggleable blue light filters, dyslexia filters, and more in future iterations. Source: extremetech.com, Adrianna Nine
