Blue Light: Is It Really Dangerous for Our Eyes?

In recent years, we have seen a significant increase in exposure to blue light, especially due to the widespread use of smartphones, tablets, and computers. This phenomenon is raising many doubts and concerns about the potentially harmful effects that blue light can have on our visual system. Scientific evidence can help us understand the nature of blue light, the mechanism by which it interacts with our eyes, and the risks associated with overexposure to this component of light, allowing us to adopt appropriate behaviors to protect our visual health.

What is blue light?

Visible light is the range of radiation to which our eyes are sensitive; it includes wavelengths between 400 and 700 nanometers of the electromagnetic spectrum (which also includes radio waves, infrared, UV rays, X-rays, and gamma rays, though these are not visible).
Within the range of visible light wavelengths, we are able to perceive blue, yellow, green, orange, red, and violet.
Blue light lies within the visible spectrum and is emitted both by natural sources, such as the sun (which emits between 24% and 30% of its light in the blue spectrum), and artificial sources. Among the latter, LED technology is today the main artificial emitter of blue light and is used in home, architectural, and street lighting, as well as being present in almost all electronic devices.
Blue light represents the highest energy radiation band within the visible light spectrum and is divided into two categories: turquoise-blue and violet-blue. The latter, having higher energy, can penetrate ocular structures and reach the retina.

The effects of blue light on the eyes

In today’s society, electronic devices are no longer used solely for work or study but also—and in some cases especially—for entertainment and leisure, particularly among adolescents and young adults. Over time, this habit results in the eyes being overexposed to blue light, which poses potential risks to some of the eye’s most delicate structures.
Blue light is high-energy radiation and is thus responsible for photochemical effects, meaning all those chemical reactions that generate free radicals, which in turn cause biological damage to cells.

The first ocular structure affected by blue light is the cornea: after prolonged screen exposure, visual fatigue may occur, with symptoms such as red, watery eyes, often accompanied by headaches. These symptoms can worsen pre-existing dry eye conditions.

The crystalline lens also absorbs blue light, which interacts with its protein components, leading to a gradual yellowing of the lens and the development of cataracts.

Finally, blue light reaches the retina—the eye’s most delicate tissue, made up of cones and rods, the photoreceptor cells that capture light and transform it into visual information.
On the retina, blue light causes oxidative stress, producing harmful compounds that reduce the vitality of retinal cells and contribute to the risk of developing various eye diseases.

Are glasses with blue light filters really useful?

Short-term effects of prolonged and constant exposure to digital screens include symptoms of visual fatigue, especially in cases where such symptoms also signal an uncorrected refractive error (such as myopia, hyperopia, or astigmatism).
In these cases, it may be necessary to wear corrective lenses equipped with blue light protection systems. These consist of specific coatings applied to the front and back surfaces of the lenses to reduce the amount of blue light reaching the eyes and to alleviate visual fatigue.

However, despite the widespread adoption of such tools, the scientific community has not yet found strong evidence that they effectively relieve eye strain or prevent eye diseases related to oxidative stress.

The retina is naturally rich in antioxidant molecules like lutein, zeaxanthin, and carotenoids, which filter blue light and are especially abundant in fruits and vegetables. These compounds serve as a natural defense against photochemical damage to our eyes.
However, risk factors such as smoking, a diet low in antioxidants, and UV exposure can deplete this important natural reserve.
For this reason, maintaining a healthy and balanced diet—combined with good habits such as limiting screen use and wearing sunglasses with certified UV filters—can help reduce photo-oxidative phenomena and preserve eye health.

Curiosity: how blue light affects rest

Blue light plays an important role not only in the visual system but also in regulating some bodily functions, such as appetite and the sleep-wake cycle.
This explains why prolonged and excessive exposure to digital devices before bedtime can lead to sleep disturbances and mood changes.
Therefore, it is advisable to limit screen use before going to sleep in order not to compromise nighttime rest.

Conclusion

Although there are still open questions regarding the long-term effects of blue light exposure on the eyes and the actual benefits of blue light filtering lenses, a diet rich in antioxidants such as lutein and zeaxanthin can certainly help reduce photo-oxidative stress in the retina and contribute to the prevention of many ocular pathologies.