The Relationship between Blue Light and Vision

The Relationship between Blue Light and Vision

The digital age has led to the creation of new diagnostic tools and pioneering laser treatments for serious illnesses such glaucoma and cataracts. But there are drawbacks to the explosive growth of technology over the last few decades. One aspect many eye health professionals are concerned about is the impact of long-term digital screen usage on eyes.

The blue light emitted from digital screens has some medical professionals and ophthalmologists concerned about potential future eye problems. While no current research supports the suggestion that blue light could cause permanent, irreversible eye damage and vision loss, it’s important to be aware of what blue light is, what the most recent studies indicate and what can be done to protect vision over the long-term.

A short wavelength and high energy

Sunlight is comprised of multiple colored light rays, including red, orange, yellow, green and blue. Light rays closer to the red end of the spectrum are longer and contain less energy, whereas those closer to the blue end of the spectrum are shorter and have higher energy.

blue light

The eye has evolved to afford humans some protection from the damage-causing UV rays in the spectrum of light, but it does not have genetic protection from the amount of blue light taken in from digital devices. The digital blue light rays are able to pass through the eye’s cornea and lens directly to the retina. The retina is the part of the eye that converts light into signals the brain understands as images. This process is what gives us the ability to see.

Blue light is related to macular degeneration

There is growing concern that blue light may cause macular degeneration, a disease primarily associated with the aging process. This is because macular degeneration occurs when the macula — a small area located in the middle of the retina containing  a large share of photoreceptor cells — deteriorates, causing the loss of the ability to see fine details. Over time, progressive photoreceptor cell death in the macula causes a person to completely lose central vision.

In 2018, University of Toledo scientists showed retinal molecules (which the macula uses to transmit images to the brain) interacted negatively with blue light. The application of blue light to retinal cells in the laboratory caused a collection of chemical reactions that can damage photoreceptor cells. The reactions are known as retinal-generated toxicity.

In spite of these concerning results, the research also emphasized the experiments were carried out in a lab setting and not directly on human eyes. Additionally, they noted it was unclear whether the amount of blue light emitted from digital screens would trigger similar toxicity levels as the amount of blue light used on cells in the experiment. Prior to the research, one of the best-known studies on the subject of blue light and eye damage occurred more than 20 years ago. The study connected blue light to photoreceptor cell death in rats, leaving many critics skeptical about blue light’s effects on human eyes.

Protecting eyes for healthy vision

While the true impact of excessive amounts of blue light on vision over the long-term remains to be seen, ophthalmologists and other medical doctors recommend limiting the use of digital devices as much as possible. However, this is due primarily to the fact that blue light can disturb the natural circadian rhythm of the body, causing problems with sleep that may affect other areas of health.

Beyond this, it is advised to limit the amount of time on digital devices to prevent conditions such as digital eye strain and computer vision syndrome. Both are characterized by blurred vision, dry eyes, eyestrain, headaches and neck and shoulder pain. The American Optometric Association recommends taking steps to avoid glare on digital screens, consciously blinking regularly to keep eyes from drying out and taking 15-minute screen breaks for every two hours spent continuously staring at a computer. The Association also suggest following the 20-20-20 rule: take a 20-second break to look at something 20 feet away every 20 minutes.