Specsavers vs. Alina blue-light blocking

Specsavers vs. Alina blue-light filter

Interest in blue-light glasses has increased significantly in recent years, partly due to the intensive use of digital screens in work and private settings. Optical retailers such as Specsavers offer glasses with a blue-light filter, while specialised brands such as Alina focus on a higher level of blue-light reduction. This article compares both approaches based on the technology used, the degree of blue-light blocking and practical applicability.

Disclaimer: This comparison is not intended to criticise or undermine the performance of one product compared with the other. The sole purpose of this article is to provide objective information, so readers can make an informed choice based on their own intended use.

Blue light and its impact on the human body

Blue light is part of the visible light spectrum and falls within the wavelength range of 380 to 550 nanometres. This light plays an important role in alertness and cognitive performance during the day. At the same time, scientific studies show that excessive exposure to blue light (particularly in the evening) can disrupt melatonin production and the circadian rhythm (Chang et al., 2015).

Research by Harvard Medical School (2020) shows that exposure to blue light in the evening affects the biological clock more strongly than other light frequencies, which can result in poorer sleep quality and longer time to fall asleep. Blue light has also been linked to digital eye strain during prolonged screen use (Rosenfield, 2016).

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Specsavers blue-light glasses and reflection technology

Blue-light glasses from Specsavers, Ace & Tate and others generally use reflection technology. A thin coating is applied to the transparent lens, reflecting some of the blue light. This type of glasses is usually transparent and has minimal impact on colour perception.

Comparative research into clear-lens blue-light coatings shows that these types of filters block an average of 10 to 20 per cent of blue light, depending on the specific coating and wavelength range (Leung et al., 2017). In practice, this amounts to average blocking of approximately 15 per cent. Specsavers and the other companies mentioned generally do not publish detailed transmission curves, making an exact comparison difficult. But a transparent pair of glasses that blocks 100% of blue light? It does not exist. 

An important disadvantage of reflection technology is that the filter layer is located on the outside of the lens. As a result, its effectiveness may decrease over time due to wear, cleaning and daily use. In addition, the filtered blue light is not absorbed but reflected, which limits the actual reduction reaching the eye.

Alina blue-light glasses and absorption nanotechnology

Alina blue-light glasses use absorption nanotechnology. Instead of a surface layer, the blue light is absorbed within the lens material itself (and converted into imperceptible heat). This means the light is genuinely removed from the spectrum before it reaches the eye.

Alina's daytime glasses block an average of approximately 35 per cent of blue light. This level of blocking is significantly higher than that of standard reflective coatings and remains stable throughout the life of the lens, as there is no wear-sensitive coating.

*Alina's red evening glasses block 99.9%, but that is not a fair comparison. Transparent or yellow lenses are also unsuitable for evening use, as they let through too much light. 

Absorption-based filters are considered more effective than reflective filters in the literature when the goal is to reduce total exposure to blue light (Lin et al., 2019). This technology also prevents unwanted reflections towards the eye and the surrounding environment.

Why we chose daytime glasses with 35% blue-light absorption

When developing our daytime glasses, we deliberately chose an approach suited to prolonged screen use during the day. Many fully transparent blue-light glasses focus mainly on filtering the extreme blue-violet part of the spectrum, typically between 380 and 415 nanometres. This choice minimises visual changes but leaves a large proportion of biologically and visually relevant blue light unaffected.

We therefore chose daytime glasses that absorb approximately 35% of blue light and actively filter the range from 380 to 455 nanometres. This broader spectrum includes the part of blue light that is dominant in modern screens and lighting. By using absorption technology, this light is absorbed within the lens material itself rather than reflected, providing stable performance during daily use.

In our view, this configuration offers the best balance between noticeable visual comfort and natural colour perception during the day. The purpose of these daytime glasses is therefore not to block blue light completely, but to reduce excessive exposure in a controlled and sustainable way during work and other screen-intensive activities during the day.

Limitations of blue-light glasses for evening use

Although blue-light glasses are often presented as a general solution, several studies show that glasses with low to moderate blue-light blocking are insufficient to protect melatonin production in the evening. Burkhart and Phelps (2009) demonstrated that only complete blocking of the blue-light spectrum had a significant impact on sleep quality.

It follows that these glasses are primarily suitable for use during the day and while working behind screens, but not for evening or night-time use. This distinction is often insufficiently made in commercial communications.

Clip-ons as a practical alternative for people who wear glasses

For people who already wear prescription glasses, an integrated blue-light coating involves additional costs and limitations. The coating is permanent, prone to wear and cannot be adapted to the time of day.

Clip-on solutions, such as those offered by Alina, provide a flexible alternative. They allow users to easily switch between having and not having a blue-light filter, without buying an additional pair of glasses or relying on a fixed coating. From a practical perspective, this better aligns with the scientifically supported distinction between daytime and evening exposure to blue light.

Conclusion

The comparison between Specsavers and Alina blue-light glasses shows that the technology used makes a substantial difference depending on your goal. Reflection technology results in limited blue-light reduction of approximately 15 per cent and is primarily aimed at visual comfort. Absorption nanotechnology, as used in Alina daytime glasses, provides higher and more durable blocking of approximately 35 per cent and reduces total exposure to blue light more effectively.

For evening use, however, neither solution provides sufficient protection against disruption of the circadian rhythm; for this, complete blue-light blocking is necessary. Making an informed choice about blue-light glasses therefore requires an understanding of both the technology and the intended time of use.