Blue Light Glasses - Is There Scientific Evidence They Work?

2025-07-02

What Is Blue Light?

Sunlight comprises various types of coloured light, including red, orange, yellow, green, blue, indigo, and violet, each with distinct wavelengths and energy levels. When combined, this array of coloured light rays produces what we know as 'white light' or sunlight.

Blue light is one of the colours in the spectrum. It has a short wavelength and high energy levels. Numerous light sources emit blue light, with the sun being the most significant contributor to our exposure. However, many artificial sources also exist, and blue light has gained attention due to its association with digital screens. Computers, tablets, smartphones, and other digital screens emit blue light. Nevertheless, the amount of time spent using these devices and their proximity to our eyes has raised concerns about the possible long-term effects of blue light on eye health.

Blue Light Glasses Scientific Evidence

First, blue light is linked to our circadian rhythm because it affects melatonin production, the hormone that regulates sleep-wake cycles. Exposure to blue light, particularly in the evening, can suppress melatonin production, making it harder to fall asleep and disrupting our natural sleep patterns.

Second, blue light has a short wavelength; it quickly penetrates the eyes, allowing almost all blue light rays to pass through the cornea and lens to the retina (the lining at the back of the eye). Although limited research exists, some experts propose that excessive exposure to blue light could harm the retina's light-sensitive cells. One animal study also discovered that blue light might induce phototoxic retinal damage.

What Is The Scientific Evidence On The Harms Of Blue Light?

Research on blue light glasses began in 1998, when the link between blue light and brain activity was first discovered. Scientists discovered new photoreceptors in the retina called retinal ganglion cells (RGCs), which are sensitive to blue light and communicate directly with the brain.

Since then, multiple studies have been conducted, and the effect of blue light on our bodies has been uncovered.

A study published in the Journal of Biological Rhythms in 2005 discusses how entrainment is a fundamental property of circadian systems that synchronizes the internal clock to the period of the entraining stimuli. Maintaining an appropriate relationship between the circadian system, the timing of sleep and wakefulness, and environmental time is crucial to maintain wakefulness throughout the day and consolidated sleep at night. This was later confirmed in the 2014 study on "Indoor and Built Environment."

A study published in the Health Promotion Journal of Australia in 2007 titled showed that even a few tens of seconds of light exposure can induce immediate and significant wavelength-dependent changes in brain activity.

Additionally, a study published in PLOS One in 2010 suggests that progress in light and health in recent years is the most significant light-induced innovation since the invention of the light bulb.

Furthermore, a study published in Life Sciences in 2011 shows that shorter wavelength light exposure increases ongoing nonvisual cognitive activity in subcortical and cortical brain areas.

Another study published in Chronobiology International in 2017 shows that exposure to artificial light at night (ALAN) can result in circadian disruption that is harmful to health. Additionally, the study notes that the International Agency for Research on Cancer (IARC) has classified shift work as a probable carcinogen to humans due to its circadian disorganization.

A recent study published in PLOS Biology in 2022 suggests that ocular light exposure influences various aspects of human physiology and behaviour, including circadian rhythms, sleep, and alertness. This confirms the 2010 Journal of Biological Rhythms study on the same topic.

Finally , a study published in Science Daily in 2022 found that even very low intensities of light exposure before bedtime can significantly reduce the production of the sleep-promoting hormone melatonin, interfering with sleep. The study suggests that young children are highly susceptible to the physiological impacts of light at night, and some are more sensitive than others.