The scam involving blue light filter screen protectors.

Blue light filtering stickers are mostly for advertising and have little effect. Photo: NYT .

Following reports about the potential harm to eyesight from blue light emitted by electronic screens, various types of screen protectors advertised as protecting against this phenomenon have emerged. With their new function, they are sold at significantly higher prices than regular accessories. However, their actual effectiveness remains unproven.

Reporters from China's CCTV randomly tested a range of products priced between 10 and 140 yuan (8,500-120,000 VND). Experiments conducted at Beijing Jiaotong University, using specialized equipment, revealed that the "blue light blocking" function of some samples was only comparable to that of plastic wrap.

“I placed the sticker in front of the spectrometer. It showed a slight reduction in blue light intensity. When I placed the food filter film, its full-spectrum suppression effect was exactly the same as the protective glasses,” concluded Chen Zheng, Professor of Engineering Physics at Beijing Jiaotong University.

This person claims that screen protectors are completely incapable of filtering blue light. However, compared to plastic wrap, they are thicker and more rigid, so applying them to a phone might provide some protection.

According to experts, the level of harmful radiation blocking is also related to the brightness of the phone screen. “The blocking value of 20% or 50% is closely related to the backlight module and the brightness setting. First, it depends on how much blue light the phone emits, then on the blocking level. For example, smartphones emit a high level of harmful radiation. If the screen protector blocks up to 50%, it's still at a harmful level. This is basically ineffective,” said Wang Guo Viet, Professor of Materials Science and Engineering, Beijing University of Science and Technology.

Regarding advertisements for screen protectors that block 99-100% of blue light, experts argue that phone screens primarily emit blue light. If all of it were truly blocked, smartphones would suffer from severe color casts and distorted image experiences.

Currently, there are no national health standards regarding the level of blue light emission from electronic device screens. Some companies advertise this function of their screens, claiming certification from international organizations such as Dolby Vision or TUV Rheinland. However, there is a lack of scientific studies demonstrating its actual effectiveness. The same applies to the screen protector industry. Adding layers of anti-blue light particles often reduces the light source, causing a yellowish tint.

Medical experts still believe that the most effective way to limit the harmful effects of blue light is to reduce the amount of time spent using electronic devices. The short wavelengths of these rays cause eye strain and worsen nearsightedness.