What’s the Deal with Blue and Orange Glasses?

If you've searched for ways to improve your sleep, you've almost certainly come across blue-light-blocking glasses. They come in all shapes and colours, from almost clear lenses to bright orange or deep red ones, all promising better sleep, less eye strain and improved wellbeing.But do they really work?The answer is more nuanced than many

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Photo by nacer eddine on Unsplash 

Why light colour matters

Our eyes do much more than allow us to see. They also contain specialised light-sensitive cells, which we call spheres, that communicate directly with the brain's biological clock, located in the suprachiasmatic nucleus (SCN).

These cells are particularly sensitive to short-wavelength (blue) light. During the daytime, this is exactly what we need. Exposure to bright, blue-enriched daylight helps keep us alert, improves mood, supports cognitive performance and strengthens the alignment of our circadian rhythm.

In the evening, however, the situation changes. If we continue exposing ourselves to bright, blue-rich light from LED lighting, televisions, computers or smartphones, our brain may interpret this as daytime. This can delay the body;s preparation for sleep.

The goal in the evening is therefore not to avoid all light, but to reduce the amount of biologically stimulating light reaching the eyes. Dim the lights and choose a warmer light tone.

Do blue-light-blocking glasses really work?

Yes, but only under the right circumstances.

Blue-light-blocking glasses can reduce the amount of short-wavelength light reaching the retina. Research has shown that wearing them during the three hours before bedtime may help some people fall asleep more easily, particularly when they are exposed to bright artificial light during the evening. However, they are not a substitute for good lighting habits.

If you're sitting in a brightly lit room with hundreds of lux reaching your eyes, simply wearing lightly tinted glasses may have only a limited effect. Likewise, wearing blue-blocking glasses during the day is generally not advisable, as daytime exposure to blue-rich daylight is essential for maintaining a healthy circadian rhythm.

Different glasses

Clear or lightly yellow lenses

Many glasses marketed for computer use have nearly transparent or slightly yellow lenses.

These usually block only a small percentage of blue light. They may slightly reduce glare or visual discomfort for some users, but they generally have little effect on circadian timing. For sleep improvement, their impact is likely to be modest.

Amber or orange lenses

Amber and orange lenses block a much larger portion of blue wavelengths. These are considerably more effective at reducing circadian stimulation during the evening and are commonly used in scientific research investigating evening light exposure.

Wearing them for approximately three hours before bedtime may help support the body's natural transition into the biological night, particularly when exposure to bright indoor lighting or screens cannot be avoided.

Deep orange or red lenses

The darkest orange or red lenses block almost all blue light and often a significant part of the green spectrum as well. These provide the strongest reduction in circadian stimulation and are sometimes used by shift workers, people with circadian rhythm disorders or individuals who are particularly sensitive to evening light.

However, they also significantly alter colour perception and are generally unnecessary for most people.

Are they better than reducing screen time?

No. For most healthy people, the priority should be achieving a strong contrast between day and night.

That means:

• Plenty of bright daylight during the morning and afternoon.

• Bright indoor lighting when needed during the day.

• Dim, warm lighting in the evening.

• Avoiding unnecessary screen use during the last three hours before bed or switching your screens to night mode.

• Darkness during sleep.

Blue-light-blocking glasses are best viewed as a practical tool for situations where reducing evening light exposure isn't possible, for example, if work requires computer use or if you are travelling.

For most people, getting plenty of daylight in the morning is likely to be more important for healthy sleep than simply blocking blue light at night.

Rather than asking, "Should I buy blue-light glasses?", a better question is: "Am I getting enough bright light during the day, and am I allowing my evenings to become progressively darker?"