To Wear or Not to Wear Blue Light Filters; That’s The Question

Agatha K Saji, B. Optom

M.Optom student, Elite School of Optometry – SASTRA University, Chennai, India

 

This world has gone through numerous dynamics over the past two decades, an inevitable change seems to be a promising aspect of technology. ⁽¹⁾ Even though this lap of luxury and comfort is a paradise to homo sapiens, it has also caused problems that are under study to help understand the issues due to substantial changes in the daily life of an individual. ⁽²⁾ This has helped the retail industry to make claims to make a profit by increasing the demand.

Blue Light, Eye and Technology: 

The blue light (380 – 500 nm) of visible spectrum is emitted from sunlight, electronic devices, and other artificial light sources. ⁽³⁾ The peak light damage is at 450 – 500 nm, and some scientists believe that photochemical change can occur with a longer duration with less intense light exposure. ⁽⁴⁾

Figure 1: Blue Light Filters; absorption of blue wavelength and transmission of the other wavelengths
[Picture Courtesy – https://tinyurl.com/3z5ter87 and modified by author]

Research reports that man-made devices have lesser irradiance than compared to natural light sources thereby not causing the assumed harmful eye effects. But what about chronic exposure? Some of the assumed effects of blue light are Digital Eye Strain (DES) (80% of users), ⁽⁵⁾ macular degeneration, melatonin suppression and psychological effects like depression, even though no studies link the relationship. ⁽⁶⁾

Transmission of Blue Light Filters:

These blue light filters are made up of chromophores which are either coated on the front surface of the lens or are injected during the manufacturing of the lens itself ⁽⁷⁾ (Figure 2). These filters are available in the form of spectacles, IOLs, and computer or smartphone-based applications.

Figure 2: The difference between a blue light filter (lens on the left with the mild yellow tint) and a lens with no filter (on the right)
[Picture Courtesy – Image captured by author]

Commonly retailed blue light filters and their transmission properties are given in Table 1., which are extracted from their respective websites. ^(8-10)

BLUE LIGHT FILTERS	CLAIMS TO BLOCK TRANSMISSION
Crizal Blue UV Capture	Up to 20 % (380 to 455 nm)
Blue Control	415 to 455 nm
BlueGuard	Up to 40% (400 to 455 nm)

Table 1: Blue Light Filters and their transmission of wavelength

The transmission of commercially available blue light filters measured using spectrophotometer was found to have 74.9 % – 90.3 % transmission, whereas a brown-tinted filter had a transmission of 86.1 % – 93.2 %. ⁽⁴⁾ Charles Woody evaluated 11 blue light filters, which showed transmission at 400 nm to range from 0 to 67.7%; 430 nm ranged from 27.2 to 81%; 460 nm ranged from 74.8 to 93.2% and 500 nm ranged from 81.7 to 95.6%. ⁽¹¹⁾ There is variance among the different brands. What about the claims by the industry? do they adhere to it, is again a question in doubt.

Knowledge Attitude and Practice among optometrists showed that almost 44% believed that blue light filters aid in reducing retinal abnormalities, whereas 50% prescribed the lenses on the basis that it alleviates DES and eye strain. ⁽¹²⁾

The Verdict:

Most studies published on blue light are on IOLs with blue light filters. A need to explore if blue light filters are just for financial exploitation and further research into this area to understand more about the effect on visual performance while using a blue light filter.

 

References:

1. Okuno, T., Saito, H., & Ojima, J. (2002). Evaluation of blue-light hazards from various light sources. Developments in ophthalmology, 35, 104-112.
2. http://www.digitalresponsibility.org/health-issues-caused-by-electronics-use Last Accessed: 25.01.2022
3. Taylor, H. R., West, S., Muñoz, B., Rosenthal, F. S., Bressler, S. B., & Bressler, N. M. (1992). The long-term effects of visible light on the eye. Archives of Ophthalmology, 110 (1), 99-104.
4. Leung, T. W., Li, R. W. H., & Kee, C. S. (2017). Blue-light filtering spectacle lenses: optical and clinical performances. PloS one, 12 (1), e0169114
5. Rosenfield, M. (2016). Computer vision syndrome (aka digital eye strain). Optometry in Practice, 17 (1), 1-10.
6. Moyano, D. B., Sola, Y., & González-Lezcano, R. A. (2020). Blue-Light Levels Emitted from Portable Electronic Devices Compared to Sunlight. Energies, 13 (16), 4276.
7. Downie, L. E. (2017). Blue‐light filtering ophthalmic lenses: to prescribe, or not to prescribe?
8. https://www.essilorusa.com/products/blue-light-eye-protection Last Accessed: 12.06.2021
9. https://www.nikon-lenswear.in/products/ Last Accessed: 12.06.2021
10. https://www.shamirlens.in/products/materials-products Last Accessed: 12.06.2021
11. https://www.aaopt.org/detail/knowledge-base-article/blue-light-transmission-characteristics-of-commercially-available-spectacle-lenses Last Accessed: 27.01.2022
12. Singh, S., Anderson, A. J., & Downie, L. E. (2019). Insights into Australian optometrists’ knowledge and attitude towards prescribing blue light‐blocking ophthalmic devices. Ophthalmic and Physiological Optics, 39 (3), 194-204.