Blue light glasses: Separating fact from fiction

PHILADELPHIA (WPVI) -- Blue light glasses are all the rage. The claim is they shield your eyes from harmful light emitted by your devices.

But are these lenses worth your money?

With hidden cameras rolling, the Action News Troubleshooters went shopping to hear the sales pitch for blue light blocking lenses.

"Is it harmful to you?" a shopper asked.

"Of course. The UV rays and all that, that's why you need to protect your eyes against it," said a salesperson.

Blue light lenses cost about $40 to $50 extra, but they sure sound worth it if you want to protect the eyes of those you love.

WEB EXTRA: Science behind blue light lenses
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Dr. Sunir Garg of Wills Eye Hospital shares some science behind blue light lenses.

"The longer you are on the electronics, they are seeing stronger prescriptions - especially for kids - because they are on their devices all day long," said salesperson.

"It can cause eye strain and eye fatigue, dry eye and , you know, even you know, macular degeneration," said another salesperson.

Seems pretty scary, so the Troubleshooters put those claims to the test by going to an expert, retina specialist, Dr. Sunir Garg at Wills Eye Hospital.

We asked Dr. Garg if blue light can cause macular degeneration.

"Not as far as we know, and I don't know where that came from, because that's not in the scientific literature," he said.

We asked if excess exposure to blue light is the leading cause of vision loss for people over 50. Dr. Garg said that's not true.

We asked if blue light could lead to premature aging of the eyes and retina damage.

"It would be scary if it were true, but it's not true," he said.

We asked if the advertising claims are false.

"They're false. There's no scientific data to back up those claims," said Dr. Garg. "We have no clinical data right now to suggest that blue lights are in any way harmful to the health of your eyes."

Dr. Garg, a spokesperson for the American Academy of Ophthalmology, said we're exposed to more blue light just from being outside than we are from our screens.

"Blue light is present in the sun. And we get way more blue light exposure from sunlight than we do from our screens on a daily basis," he said.

Bottom line? You might want to do as the doctor does.

"I just got my glasses now, first set of bifocals from my wife, who's an ophthalmologist, and there's no blue filter on these either," he said.

We reached out to a leading lens manufacturer who cited two studies in which individuals wearing blue light blocking lenses reported feeling less eye strain and fatigue. However, the manufacturer also noted more research needs to be done.

"Those studies came out more than five years ago without much follow up by other researchers. These are not necessarily standard tests, and are not sufficiently large to detect a significant difference. Additionally, it's not clear from the papers whether the lenses blocked similar amounts of light independent of the blue blocking component," said Dr. Garg.

Regardless of your vision, Dr. Garg said everyone using devices should take frequent breaks every 20 minutes and look 20 feet off into the distance for 20 seconds.

Another tip is to switch your phone to night mode about an hour or two before going to bed. That changes the blue light to a more yellow color which doesn't keep you awake.

Dr. Garg said you can also use eye drops or artificial tears to help with drying.

Action News received the following statement from a leading lens manufacturer:

Visual Fatigue and Blue Light

Blue light is proliferating in our day to day lives. Of course blue light has always impacted our eyes through sunlight, the strongest source of blue light. However, blue light is now ubiquitous indoors as well, from LED computer screens to LED overhead lighting to devices, exposing our eyes to more blue light than even before. Scientists are studying the impact of the increased exposure to blue light. In turn, companies are developing products to address the potential negative implications of blue light on our eyes. Scientific studies are still early in their development, but several studies are indicating that blue light increases visual fatigue and the reduction of blue light can reduce visual fatigue symptoms.

Two of the relevant studies are summarized below.

Isono H. et al. The Effect of Blue Light on Visual Fatigue When Reading on LED-backlit Tablet LCDs. Proceedings of ITE & SID 2013 annual conference. Subjects were assessed for visual fatigue when using LED-backlit tablets either in regular white or blue-blocking sepia backgrounds. The sepia background reduced the eyestrain, suggesting that the high intensity blue light emitted from LED-backlit tablets adds to visual fatigue. Subjective evaluation of the participants also suggested more eye strain, blurry vision and tiredness with the white background in comparison with the sepia background.

Ide T., Tsubota K. et al.Effect of Blue Light-Reducing Eye Glasses on Critical Flicker Frequency. AJPO 2015: 33. Subjects were divided into 3 groups and wore 54% or 36% blue-blocking lenses versus control clear lens while performing intensive computer work for two hours. The Critical Flicker Frequency (known as CFF) was measured as a marker of visual fatigue and questionnaires on 13 symptoms of visual fatigue were submitted. The higher the blue-blocking effect of the lens, the lower the reduction in CFF, suggesting that blocking short-wavelength (blue) light can reduce eye fatigue. The study concluded that [b]ecause many individuals have CVS (computer vision syndrome), the subjective and objective reductions in eye strain, mental stress, and musculo-skeletal pain achieved through the use of light-blocking computer glasses are worth the associated costs.

Additionally, it should be noted that some lenses which are marketed as providing blue light filtering also provide "accommodative relief", which is magnification in the lenses which will also reduce eyestrain independent of the blue light protection.

Although more research remains to be done on this important topic, the research that has been concluded to date clearly supports the use of blue light filtering lenses while further studies are conducted to confirm the valuable properties of the lenses.
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