According to The Vision Council, over 90 percent of Americans use digital devices for two or more hours per day and upwards of 50 percent are not aware of blue light.
Blue light is a wavelength between 400−495 nm apart of the visible light spectrum ranging from 400nm to 700nm. It stimulates the eye to perceive color or influence the brain’s sleep-wake cycle. Unlike the sun, other sources of blue light are artificial like digital screens (TVs, computers, laptops, smart phones and tablets), electronic devices, and fluorescent and LED lighting. So, it is arguable that one is exposed to it constantly in our current digital environment.
But there is more to this story than meets the eye.
The eyes are equipped with natural “sunglasses” called lutein and zeaxanthin, which are concentrated in an area called the macula of the eye. These carotenoids, which are a sub-type of vitamin A, give the macular region a yellow color. This helps to mitigate the damage but some photoreceptors in the retina at the back of the eye are still susceptible to damage by high energy light. The macular pigment has a peak absorption at about 460 nm.
Blue light is not all bad. It also acts as a natural signal to the brain that it is daytime. This is important to make sure you don’t get sleepy in the middle of the day. This is achieved by balancing a naturally occurring hormone called melatonin.
Melatonin is a hormone produced in the pineal gland and it’s responsible for regulating the body’s sleep-wake cycle. Production of this hormone starts after sunset and can increase to 10x the daytime concentration during the night although it does decrease with aging. Darkness triggers the body to produce more melatonin which signals the body to prepare for sleep. Light (in particular, blue light) decreases the production of melatonin, signaling the body to prepare for wakefulness. It has been found that some people that have trouble sleeping actually have low levels of melatonin and it is thought that melatonin supplementation may help with this.
The natural night-time secretion of melatonin is suppressed by relatively dim light when the pupils are dilated. It has been suggested that this is the reason prolonged use of devices such as laptops and smartphones before bedtime can have a negative impact on secretion and disrupt the circadian rhythm, and ultimately, the ability to sleep.
So, on a very simplistic level, it can be said that our circadian rhythm is set by a balance between blue light exposure and melatonin secretion by the pineal gland. The eyes and brain work together to achieve this balance.
Preventative measures to obtain this balance can be implemented with the following tips:
· Stop non-essential notifications on electronics
· Try to setup a consistent time before bed to avoid electronics, ideally two hours
· Create phone/electronic free areas in the home such as your dinner table
· Use blue blocking glasses/shields that have the proper percent blocking capabilities
· Dietary increase of Lutein and Zeaxanthin rich foods such as kale and spinach, and possibly high-quality supplements
· Implement the 20/20/20 rule for eye fatigue
· Adjust brightness settings on electronics
For more information, please attend two opportunities: Georgian Court Wellness 3/14/2020 Expo 3:30-4pm and Dean’s Shrewsbury 3/18/2020 6-7pm. Dr. Neda Gioia is a licensed optometrist with certification through Functional Medicine University and a current CNS candidate. She is a fellow of the Ocular Wellness Society, a member of the Institute of Functional Medicine and has been featured in Review of Optometry and Women in Optometry. She is the owner and founder of Integrative Vision Corp., in Shrewsbury, NJ. Currently accepting new adult and pediatric patients 732.389.2792, integrativevision.com