Rays on the blue end of the visible light spectrum have shorter wavelengths and more energy. Blue light generally is defined as visible light ranging from 380 to 500 nm. Blue light sometimes is further broken down into blue-violet light (roughly 380 to 450 nm) and blue-turquoise light (roughly 450 to 500 nm). Approximately one-third of all visible light is considered high-energy visible (HEV) or "blue" light.
Display screens of computers, tablets, smartphones and other digital devices emit significant amounts of blue light. The amount of HEV light these devices emit is only a fraction of that emitted by the sun. But the amount of time people spend using these devices and the proximity of these screens to the user's face is concerning optometrists about possible long-term effects of blue light on eye health.
The cornea and the lens of the eye are very effective at blocking UV rays from reaching the retina. Actually, only less than 1% of UV radiation from the sun reaches the retina. It is still important to wear 100% UV blocking sunglasses to protect these and other parts of the eye to prevent cataracts, macular degeneration and even cancer. Unlike UV light, virtually all visible blue light passes through the cornea and lens and reaches the retina. Laboratory studies have shown that too much exposure to blue light can damage cells in the retina. This damage mimics changes in the back of the eye similar to that of macular degeneration, which can cause permanent vision loss. Although more research is needed, eye care providers are concerned that the added blue light exposure from computer screens, smartphones, and other digital devices might increase a person's risk of macular degeneration later in life.
Upon entering the eye, HEV light scatters more easily than other visible light and is not as easily focused. When you're looking at computer screens and other digital devices that emit significant amounts of blue light, this unfocused visual "noise" reduces contrast and can contribute to digital eye strain.
Computer glasses can be helpful to reduce blue light exposure from computers and other digital devices. They can be specially prescribed to optimize your vision specifically for the distance from which you view your devices. Here at Omni Eye Specialists, we offer special glare-reducing anti-reflective coatings that block blue light from both natural sunlight and digital devices.