Blue light is a high-energy visible light, defined with a wavelength that falls between 450-495 nm. Like ultraviolet light and radiation, it poses both benefits and dangers to human beings. Below, we detail some facts about blue light.

Understanding Blue Light

While blue light is primarily present in sunlight, it is becoming increasingly common indoors as well. This is due to the popularity of fluorescent and LED lighting and appliances. Flat screen televisions, computer and laptop display panels, smartphones, and tablets are all significant sources of blue light. Even though they only emit a fraction generated by the sun, the amount of time we spend in close proximity using these devices have had many eye care professionals concerned about its possible long-term effects.

Blue Light’s Effect on the Eye

While the cornea and lens of the eye are effective at blocking the sun’s ultraviolet rays from reaching the retina, all blue light passes through the anterior parts of the eye.

Because the light can make its way to the retina, it can damage the light-sensitive cells contained within. This results in changes to the retina that can cause degeneration of the macula, which can then lead to permanent loss of vision as the macular pigment deteriorates.

If you have ever spent over two or more hours in front of a computer or mobile device, chances are you’ve also experienced digital eye strain. It is defined as physical eye discomfort after using digital devices for extended periods of time. Blue light contributes to that strain, because phones, laptops, and tablets all use LEDs, which emit significant amounts of blue light.

Benefits of Blue Light

Blue light is important in regulating the body’s natural sleeping and waking cycles, also known as the circadian rhythm. Exposing yourself to it during the day can help you maintain that rhythm, but it can be disrupted if you expose yourself to artificial blue light sources excessively at night. You may want to look into lowering the brightness on your devices or using its “night mode” if it is available. In this way, you can prevent sleepless nights and feeling fatigued during the day.
High-energy visible light like blue light has also been shown to boost alertness, memory and cognitive function, as well as elevate your mood. For those who suffer from seasonal affective disorder (a depressive condition that is tied to the changing of seasons), light therapy using HEVs is usually administered.