The Truth Behind Blue Light Blocking Glasses: Do They Really Deliver?

LULU GARCIA-NAVARRO, HOST:

Screen time has increased during the pandemic. Many of us are indeed working from home. Children are being educated at home, interacting with computers instead of raising their hands in classrooms. This has led to what is commonly referred to as digital eye strain, characterized by fatigued and dry eyes from excessive screen exposure. Hence, some individuals have resorted to blue light-blocking glasses. Sales have surged more than double throughout the pandemic, yet are they truly worth the price? Dr. Mark Rosenfield, a professor at the College of Optometry at the State University of New York, has conducted two studies examining the efficacy of blue light-blocking glasses in relation to digital eye strain, and he joins us now. Welcome to the program.

MARK ROSENFIELD: Thank you.

GARCIA-NAVARRO: What insights did your study reveal concerning the use of these glasses?

ROSENFIELD: Both of our studies revealed that the blue-blocking filters demonstrated no impact, no significant influence on digital eye strain. This outcome did not come as a significant surprise to us since there is no evident mechanism through which blue light should induce digital eye strain.

GARCIA-NAVARRO: I have to admit that feels like a major revelation, but I’m not taken aback. It often appears that such products could merely be gimmicks. How did you validate that in your research?

ROSENFIELD: Well, we conducted two studies. In the first, we employed a filter that blocked nearly 100% of the blue light. Subjects were asked to read from a tablet for approximately 30 minutes. We saw no noteworthy difference in symptoms, whether they wore the blue-blocking filter or simply a tinted lens. Since that filter blocked virtually all blue light, something rarely seen in commercially available lenses, we repeated the study. This time, we utilized common prescription lenses that only block about 20 to 25% of the blue.

The second study followed a double-blind approach; therefore, the participants were unaware of whether they were looking through the blue-blocking filters or just a transparent lens. The experimenter was also unaware of which lens the subjects were viewing. Again, we observed precisely the same result – that the blue-blocking filters caused no significant alteration in symptoms of digital eye strain.

GARCIA-NAVARRO: What is the underlying cause of digital eye strain?

ROSENFIELD: We believe it’s not particularly the screens themselves but rather the usage habits of people. They tend to hold the devices at quite close distances, especially smartphones. We noted that individuals sometimes held them as closely as 8 to 9 inches, whereas printed materials are generally held around 16 inches away. Additionally, people tend to gaze at these screens for extended periods without taking breaks.

GARCIA-NAVARRO: Do these glasses have any utility whatsoever?

ROSENFIELD: The sole potential benefit might be that studies indicate blue light can disrupt our body’s light cycle. We have a natural rhythm that helps us discern when we become fatigued and when it’s time to sleep. If you choose to view a screen late at night, which is probably not advisable—but regrettably, many of us do—then blue-blocking filters might serve a purpose in that context.

GARCIA-NAVARRO: What actions can we take to reduce digital eye strain, considering that many of us need to spend time in front of a screen?

ROSENFIELD: Well, taking breaks is essential. We advocate the 20, 20, 20 rule: every 20 minutes, it’s beneficial to look at something at least 20 feet away for at least 20 seconds. Aim to expand your viewing distance, especially with handheld devices like smartphones or tablets. Do not hold them too closely; the nearer you hold something, the harder your eyes work to focus. We recommend that such devices should always be held at a distance of no less than 16 inches away.

GARCIA-NAVARRO: Dr. Mark Rosenfield is a vision researcher at the State University of New York. Thank you very much.

ROSENFIELD: My pleasure. Thank you.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.

NPR transcripts are created on a rush deadline by an NPR contractor. This text may not be in its final form and may be updated or revised in the future. Accuracy and availability may vary. The authoritative record of NPR’s programming is the audio record.