TUV

TUV Rheinland, one of the world’s largest independent testing service providers, and Healthe, a world leader in eye health for electronic devices, has created a new blue light filtration standard for digital devices in collaboration with the Eyesafe® Vision Health Advisory Board. The new TUV Rheinland standard specifically provides customers a Retina Protection Factor or RPF, an easy to use guide that measures and identifies the level of high-energy visible blue light being filtered from a device display while maintaining color quality. More information around the developed standard may be found below.

 

TUV Rheinland Blue Light Filtration Standard for Managing Blue Light Emissions of Personal Electronics

The evolution in digital screen technology has advanced dramatically over the years. Over 3.6 billion people use the internet, and this number is rapidly increasing. Almost half of the world population is using the internet.  In 2017 around 1.1 billion computers, television sets, and cell phones were sold globally, which illustrates the numbers of individuals who spend time in front of computer screens, video game consoles, or other video monitors. Until the advent of artificial lighting, the sun was the major source of lighting, and people spent their evenings in darkness. Nowadays, we are surrounded by artificial sources of light. These electronic devices use LED backlight technology to help enhance screen brightness and clarity. These LEDs emit very strong blue light wavesin the short-wavelength region (i.e., the blue range at ~460 nm). Cell phones, computers, tablets and flat-screen televisions are just among a few of the devices that use this technology.  Because of their wide-spread use and increasing popularity, we are gradually being exposed to more and more sources of blue light and for long periods of time.

 

Research Driving Standards for the Industry

 

Recent studies have identified growing concerns over potential long-term eye and health impacts from digital screen usage and cumulative blue light exposure emitted from almost all digital devices. More specifically, a combination of factors including the proximity at which we view digital screens, the frequency and length of time of this use, physical responses to screen habits, and exposure to blue light, have been reported to cause visual discomfort in 65 percent of Americans (1).

 

Blue violet light has also been associated with possible harmful effects, particularly on the retina because of its high energy, short wavelength light in the narrow range (415-455nm) (2). In addition cumulative blue light exposure from digital devices is linked to slow degeneration of the retina, which could accelerate long-term vision problems such as age-related macular degeneration (AMD) and cataracts (3). While this high-energy light is beneficial for aiding cognitive functions, such as alertness, memory and emotion regulation, it can also disrupt sleep by suppressing the natural release of melatonin (4). Emerging research suggests cumulative and constant exposure to the blue light emitted from backlit displays can damage retinal cells (5).

 

Recent research has found that filtering out blue light from LED screens before bed time of teenagers produced significant positive health benefits by curbing LED-induced melatonin suppression and decreased alertness brought on by blue light before bedtime (6). Two recent studies showed that patients with unstable tear film achieved better results in visual acuity tests when using a blue light filter. Another study showed that the use of blue filtering can reduce the glare and photo-stress associated with prolonged exposure to intense light (7, 8, 9)

 

TUV Rheinland Blue Light Filtration Standard and Certification

 

Given the growing body of research around the potential health impacts of blue light exposure and the benefits of blue light filtering, the TUV Rheinland Blue Light Filtration Standard provides transparency on the topic of blue light filtration and builds upon upon existing ANSI Z80.3 and CE-166 Standards. The RPF or Retina Protection Factor value is based on the reduction of Blue Light Hazard as outlined in the ICNIRP guidelines published in Health Physics  105(1):74-96; 2013. The particular table is Table 2, page 84. That same table has been adopted in the ANSI Z80.3 and CE-166 Standards.

 

The standard identifies the need for lower transmission in the areas of highest toxicity centered between 435nm and 440nm. The toxicity of the light source (such as a display) may be first calculated using a spectrophotometer or spectroradiometer to measure the emissions across the visible spectrum and then multiplying those values by the factors in the toxicity scale above. The resulting sum of those values is the weighted toxicity level for that light source and is the toxicity without the filter. The filter is then placed between the light source. The measurement is made again and the toxicity of the light is again calculated by the same procedure. The difference between those numbers is the reduction of the toxicity and is expressed as a % reduction –
(100 X [Toxicity without film – Toxicity with film]/Toxicity without film) = (x)% Reduction = RPF(x) or in the case of RPF film the RPF value (i.e. 15% reduction, RPF15).

 

Certification of Display and Film

 

So as stated above, to certify an RPF Film for a particular RPF value (% reduction in Blue-Light Hazard) a display can be measured without the RPF film and then that same display measured again with the RPF installed. The goal is to get a value of the change in Blue-Light Hazard.  Alternatively, measurements can be made on a display with an RPF film installed in its final configuration but only covering ½ of the display surface (i.e. behind the cover glass over ½ of the displays surface).

 

In either case measure the emission for the display with a spectroradiometer – with and without the film. It would be best to take several measurements at different points across the monitor or on both sides of the monitor (in corresponding locations to each other – i.e. center-left:center-right, top left corner:top right corner, etc). Average the measurements and calculate the difference in blue light toxicity, convert it to a percentage reduction for the RPF film and certify the film at the corresponding RPF level.

The Retina Protection Factor (RPF) = ratio of the sum of the spectral weighting factors of blue light hazard emissions (300-700nm) with and without filtration (based on ANSI Z80.3)

 

Color Management and D65 Illumination Rating

The TUV Rheinland Blue Light Filtration standard identifies the importance of color and selectively filtering blue light while maintaining crisp and vivid color transmission in digital displays.

The CIE (International Commission on Illumination) 1931 color spaces were the first defined quantitative links between physical pure colors (i.e. wavelengths) in the electromagnetic visible spectrum, and the physiological perceived colors in human color vision. The mathematical relationships that define these color spaces are essential
tools for color management when dealing with color inks, illuminated displays, and recording devices such as digital cameras. Many digital devices, whether they are phones, tablets or monitors, strive to create an illumination rating known as D65. The CIE positions D65 as the standard daylight illuminant, and is intended to represent average daylight. As we filter blue light from display emissions, we also strive to minimally impact D65 illumination ratings.

As such, the standard not only identifies the selective filtration of blue light, but also the effective management of CIE color transmission and D65 illumination ratings.

 

Certification Table & Requirements

The TUV Rheinland Blue Light Filtration standard includes requirements for RPF Level, Shift of CCT and Luminance Reduction as follows:


Conclusion

Given the growing body of research around the potential health impacts of blue light exposure and the benefits of blue light filtering, the TUV Blue Light Filtration Standard provides transparency on the topic of blue light filtration and builds upon upon existing ANSI Z80.3 and CE-166 Standards. The RPF or Retina Protection Factor value is based on the reduction of Blue Light Hazard as outlined in the ICNIRP guidelines published in Health Physics  105(1):74-96; 2013. The particular table is Table 2, page 84. That same table has been adopted in the ANSI Z80.3 and CE-166 Standards. Specifically, the following adjustments are proposed for the industry and applications for Accessory and Display product applications:

  1. 1. Managed light emissions in the blue violet spectrum from 415-455nm
  2. 2. Maintain CCT value in acceptable range
  3. 3. Maintain spectral transmittance of visible light
  4. 4. Maintain color accuracy

 

Blue Light Exposure Research & Sources:

  1. 2. 2016 Nielsen Audience Report, 1Q Report, http://www.nielsen.com/us/en/insights/reports/2016/the-total-audience-report-q1-2016.html, June 27, 2016.
  2. 3. American Psychological Association, Children and Electronic Media: How Much is Too Much? http://www.apa.org/pi/about/newsletter/2015/06/electronic-media.aspx, June 2015.
  3. 4. Progress in Retinal and Eye Research, Light-emitting diodes, (LED) for domestic lighting: Any risks for the eye? F. Behar-Cohen, https://www.ncbi.nlm.nih.gov/pubmed/21600300, May 14, 2011.
  4. 5. American Optometric Association, The 21st Century Child: Increased Technology Use May Lead to Future Eye Health and Vision Issues www.aoa.org/newsroom/the-21st-century-child-increased-technology-use-may-lead-to-future-eye-health-and-vision-issues, July 28, 2015.
  5. 6. The Vision Council, Eyes Overexposed: The Digital Device Dilemma, http://2014.thevisioncouncil.org/sites/default/files/2416_VC_2016EyeStrain_Report_WEB.pdf, January 6, 2016.
  6. 7. Proceedings of the National Academy of Sciences of the United States of America, Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness, Chang AM, Aeschbach D, Duffy JF, Czeisler CA, http://www.pnas.org/content/112/4/1232.abstract, November 26, 2014.
  7. 8. NPJ Aging Mechanisms of Disease, Hatori M, et al. Global rise of potential health hazards caused by blue light-induced circadian disruption in modern aging societies. https://www.nature.com/articles/s41514-017-0010-2, June 16, 2017.
  8. 9. Gianluca T, Ian F, Kazuo T, Effects of Blue Light on The Circadian System and Eye Physiology, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/, January 24, 2016.
  9. 10. PLOS One, Phototoxic Action Spectrum on a Retinal Pigment Epithelium Model of Age-Related Macular Degeneration Exposed to Sunlight Normalized Conditions, http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0071398, August 23, 2016