Phillip Yuhas, a professor of optometry and vision science at Ohio State, believes that blue light is not as damaging as it is made out to be. Credit: courtesy of Phillip Yuhas
These days, college is more than blackboards and notebooks. It’s laptops and tablets too, and with that shift may come health side effects.
Phillip Yuhas, professor of optometry and vision science, said that blue light can emit from sources such as computers and light bulbs, but the sun and cellphones are the biggest sources. Studies have shown this type of light can have a large impact on retinas.
“Blue light is visible light that not only can get through to the back of the eye, but it stimulates the cells in the back of the eye that can sense it. It’s short wavelength, which means it’s high energy, and that’s where people think the damage comes from,” Yuhas said.
Studies have shown blue light to have the largest impact on the retina, Yuhas said. However, most studies were performed on lab animals, rather than humans, he said.
“Our eye has protective mechanisms against blue light, so things like macular pigment and pigment called melanin in the back of our eye are protective against the negative effects of blue light,” Yuhas said.
Blue light may be more damaging in theory and in animals than it is in the real world on humans, Yuhas said.
However, blue light can reset the circadian rhythms — natural processes that regulate the sleep-wake cycle, repeating roughly every 24 hours — which can lead to a decreased ability to have a good night’s sleep, Yuhas said.
“If you look at your screen before bedtime, certainly your screen can reset the circadian rhythms, but cutting out blue light alone doesn’t help,” Yuhas said. ”Although blue light is the most effective at setting our circadian rhythms, it’s not the only light that can do this.”
Yuhas said he recommends dimming the lights as it becomes closer to bedtime and staying off phones before bed. Long-term use of devices can have detrimental effects on eyesight, including dry eye, he said.
“When we’re on our phones, we don’t blink. Our blink rate goes down from about 12 blinks a minute to about six. So when we don’t blink, the tears evaporate off our eyes, so our eyes become dry. Our eyes feel strained and tired,” Yuhas said.
Dr. Meena Khan, a physician at the Wexner Medical Center at Ohio State, said protecting against blue light is a good idea to combat its negative effects.
“As time goes on in electronics the light becomes more crisp, the picture is more crisp — there’s a lot more brightness that comes from it, and a lot of that is due to enhancing the blue wave light,” Khan said. “Looking at a screen for sustained amounts of time can lead to eye strain and headaches. Having intermittent breaks from the screen is helpful for that.”
Using device features such as blue light filters have not been proven to protect against eye damage. However, there is no disadvantage to using them, Khan said.
The main issue with blue light is the sleep loss it can cause, Khan said. She added that blue light can cause a decrease in melatonin, which signals the brain that it is time to sleep.
“Maybe eliminate screen time a half- hour to an hour before bed, and expose yourself more to dim light during that time to minimize blue light exposure during that time,” Khan said. “Our brains equate light with wakefulness and darkness with sleep.”
