Blue block glasses work by blocking or filtering out blue light, which is a type of high-energy visible (HEV) light that is emitted by electronic devices such as computer screens, smartphones, and televisions. The lenses of blue block glasses are specially designed to absorb or reflect blue light, preventing it from entering the eyes.

Blue block glasses or blue light glasses typically block blue light in the range of 400 to 500 nanometers, which is the portion of the blue light spectrum that is most likely to cause eye strain and disrupted sleep. By blocking or reducing this portion of blue light, blue block glasses may help to reduce symptoms of digital eye strain and improve sleep quality.

It's important to note that blue block glasses are different from blue light glasses, which also filter out blue light but typically block a wider range of wavelengths. Blue block glasses are also different from regular sunglasses, which may not block blue light.

While there is some evidence to suggest that blue block glasses may be effective in reducing eye strain and improving sleep quality, more research is needed to fully understand their benefits and limitations. Additionally, it's important to note that blue block glasses should not be used as a substitute for good sleep hygiene practices, such as reducing screen time before bed and maintaining a consistent sleep schedule.