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Are blue light glasses necessary?


Q: Many of my co-workers use glasses that block blue light when they are on their computers. I am interested in getting a pair but want to know more about how they can help. A:

Blue light glasses are gaining in popularity, but it is important to understand what blue light is. Blue light is one of the colors in the visible light spectrum. The others are red, orange, yellow, green, indigo and violet. When combined, they create white light. When the sun is shining, this is natural white light.

Blue light has a shorter wavelength with higher energy: 400 to 500 nanometers. Blue-light exposure can affect the retina, the layer of cells lining the back wall inside the eye that senses light and sends signals to the brain so you can see.

Concerns about blue light

Exposing the retina to shorter light wavelength­s is the basis of “blue-light hazard” and contribute­s to phototoxic­ity or sensitivit­y to light. In animal studies, prolonged exposure to natural blue light has been shown to damage the retina.

LED and compact fluorescen­t lamps also give off blue light. LEDs are used for the backlighti­ng of computer screens, laptops, TVs and smartphone­s. Fortunatel­y, the level of blue light from these devices is significan­tly less than the levels of blue light in natural daylight.

However, at night, blue light exposure can potentiall­y cause sleep issues by shifting your circadian rhythm, which is the body’s internal clock. Research has suggested that excessive exposure to visible blue light also can cause eyestrain. Up to 69% of computer users report eyestrain, also known as computer vision


What research has found

Since 2008, research into blue-blocking or filtering products, such as blue-blocking glasses, has increased. These products decrease the transmissi­on of ultraviole­t light involving wavelength­s between 440 and 500 nanometers. Some devices offer blue light-filtering settings that reduce the transmissi­on of short wavelength­s of light.

Studies have been conducted with adults on the benefits of blue-blocking lenses — whether these lenses alleviated eyestrain and discomfort when using digital devices and if sleep quality improved when the lenses were used in the evening. But in reviewing the research, no significan­t improvemen­t in vision performanc­e or sleep quality has been found from using blue-blocking lenses.

Ways to reduce eyestrain

Since the amount of blue light from the devices used at work, school and home is less than that of natural sunlight, and eyestrain hasn’t been found to be related to blue light, what can be done to prevent it?

Prolonged screen time decreases your natural blink rate, which reduces the film of tears covering your eyes, making them dry.

You can prevent this by: Taking frequent breaks during screen time. Try following the “20-20-20 rule.” Every 20 minutes, look at an object 20 feet away for at least 20 seconds.

Using artificial tears to refresh your eyes when they feel dry.

Getting a vision exam to evaluate an uncorrecte­d eyeglasses prescripti­on or refractive error. This helps identify any issues with focusing, which could cause eyestrain.

Rather than investing in blue-blocking glasses, consider:

Monitoring the length of screen time.

Reducing the duration of your screen time.

Taking frequent breaks. If you are still experienci­ng eyestrain or other eye issues, make an appointmen­t with a provider for a thorough eye examinatio­n to ensure any problems are caught early.

— Gretchen Kelly, O.D., Optometry, Mayo Clinic Health System, La Crosse, Wisconsin

Mayo Clinic Q&A is an educationa­l resource and doesn’t replace regular medical care. Email a question to MayoClinic­Q&A@mayo. edu.

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