Updated: Aug 19, 2021
Technology advances faster than our knowledge of how it affects the human body. Digital screens have become common in the modern world, but there’s growing concern that they may be having an adverse effect on eye health. At Two Trees Optometry, we can help patients with issues like digital eye strain and other computer-related vision problems. One area of concern is the blue light wavelengths used in many digital screens. While some claims you’ll find online are exaggerated, evidence suggests that consumers shouldn’t ignore the potential dangers of blue light exposure.
The risk of blue light exposure comes from the light with the lowest wavelengths that are still visible to humans. Blue light is generally defined as visible light ranging from 380 to 500 nanometers, which makes it the lower third of the visible spectrum of light. Sunlight is the most significant source of blue light exposure for most people. The modern world has many indoor sources of blue light, such as fluorescent and LED lighting, as well as the display screens on devices like smartphones, tablets, and flatscreen displays. Even when they appear white, LEDs have a peak emission in the blue light range (400-490nm range). Virtually all visible blue light passes through the cornea and lens and reaches the retina. What's worse is that these effects are based on cumulative exposure.
Research on the long-term effects of blue light exposure is in the early stages. The screens and LED lights in question haven’t been around long enough for a lot of long-term human studies to have been done. However, preliminary evidence suggests that blue light exposure can have negative eye health effects. Some studies indicate that the cumulative effect of blue light exposure may affect cones (the photo-sensitive cells responsible for central and color vision) and the retinal pigment epithelium (cells responsible for nourishing the retinal cells). Additionally, Lutein, a blue-blocking pigment, is found in healthy human retinas. The fact that the body has a natural defense against blue light exposure is further evidence of the potential harm.
Blue light exposure may be linked to macular degeneration. The research into this possibility is ongoing. Early experimental studies have noted that the potential damage to the retinas from excessive blue light exposure is causes changes that resemble those of macular degeneration, which can lead to permanent vision loss. One of the most significant issues is that researchers are still trying to work out how much blue light exposure is too much.
Another thing to consider is the effect blue light has on your ability to sleep. Blue light affects the body's circadian rhythm, which is the natural cycle of waking and sleeping. Blue light stimulates us and upset a person's circadian rhythm by keeping them awake. This dynamic is why too much blue light exposure late at night from your phone, tablet, or computer can make it harder to sleep. A lack of sleep is linked to many physical and mental health issues. Indirectly, blue light exposure can exacerbate conditions like anxiety and heart disease.
Parents should also be concerned about the harmful effects blue light can have on their children. Cumulative exposure is what matters the most with blue light exposure, and kids can receive more blue light in less time because their eyes are still developing. As noted by the American Optometric Association, “A child’s crystalline lens is more transparent to short wavelengths – such as blue light – than that of an adult, making children more sensitive to blue light effects than adults.”
It's impossible to remove all blue light sources from your life, and it's not necessary if you take a few precautions. People who spend a lot of time looking at screens should consider getting glasses that can reduce the adverse effects of over-exposure to blue light wavelengths.
If you have questions about blue light, computer-related eye strains, or any other vision problem, Two Trees Optometry in Ventura, CA can help. Our doctors and staff can work with patients of all ages, and we’re highly experienced in finding the ideal solution to help patients with eye care issues. Visit our website to schedule an appointment for an eye health checkup.