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Blue light: What’s the risk?

November 21, 2019 | UCI Health
uci health ophthalmologist dr mitul mehta with patient

UCI Health ophthalmologist Dr. Mitul Mehta paid special attention to the booth next to him at a technology conference he attended last year in San Francisco.

There, the founder and owner of a company called EyeJust was touting her product, an iPhone screen protector that she said protected more than the screen: It shielded its users from the harmful effects of blue light.

Mehta, an expert on blue light rays at the UCI Health Gavin Herbert Eye Institute (GHEI) in Irvine, wondered if her claims were true and asked the owner how she knew the filters were doing their job.

“Blue light is associated with retinal damage and dry macular degeneration,” says Mehta, an ophthalmologist who specializes in medical and surgical treatment of retinal diseases.

“The blue spectrum is a higher energy wavelength of light and those have been associated with a lot of things. The most well-established of these is interfering with sleep.”

Benefits of blue light

Blue light isn’t all bad, Mehta says.

Special lamps that emit blue-spectrum waves help some people who become depressed during the shorter, darker days of winter.

Staring into a phone for hours every day is another matter, however, especially when you consider that the newly ubiquitous LED lights also give off much more blue-spectrum light.

Melatonin suppression disrupts sleep

Cell phones can be a special problem when used before bedtime, Mehta says. In part, that’s because blue-spectrum light can suppress the body’s production of the sleep hormone melatonin, interfering with the body’s circadian rhythms.

In addition, bedtime cell phone viewing is a time when people are more likely to have other lights off, which means their pupils are dilated, taking in more of the blue light.

Many cell phones come equipped with “red shifting” for evening viewing, putting more red spectrum rays into the light they emit. While this reduces blue light exposure, but it also makes the screen less readable, Mehta says.

Designing a blue light-blocking filter

Those were among the reasons Gigi Mortimer, who had been a designer of sunglasses, was motivated to create her blue light filter, which so far is made only for Apple products.

“The average American is spending seven-plus hours on their phone,” Mortimer says. “When I realized it was wrecking my health and my children’s health because we couldn’t sleep, I went on a mission to find a solution.”

The question was how effectively the screens worked, and though Mortimer had paid a third-party tester to check out her product, she was intrigued by Mehta’s questions.

Testing filter's effectiveness

She also wondered whether she could enlist a prestigious, academic eye institute to do first-rate scientific testing. He, in turn, was intrigued by the idea of finding out exactly how well the screens did work to filter blue light.

Two GHEI resident physicians, Dr. Jordan Conger and Dr. Andrew Smith, carried out the tests.

The results?

“The blue light screen filter did a pretty decent job of screening the blue light,” Mehta confirms.

“Not as much as red shifting, but it blocked a significant percentage of blue-spectrum waves at different settings. And the screen was much more visible with the filter, the same as if you were seeing it without one.”

Mehta says research into the blue light filters will continue at GHEI, with funding from EyeJust, in hopes of adding to and refining its products’ protective features.

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