ErgoPractice News – September 2019
The color rendering index (CRI) or corrected color temperature (CCT) of LED headlight beams will be different from the LED chips hardware depending on the beam-forming optics. If beam-forming optics are not true color, achromatic beam-forming optics, then readings may vary depending on where the reading is taken within the beam.
Figure 1a shows a color strip under the illumination of a neutral LED headlight using SurgiTel true color, achromatic beam-forming optics and Fig1b shows images under the illumination of traditional, non-achromatic beam-forming optics which are used by all major manufacturers of LED headlights. CRIs and CCTs measured at various locations of the beam formed with SurgiTel true color beam-forming optics are identical over the entire beam. As shown in Figure1b however, CRIs and CCTs measured with beams formed with traditional beam-forming optics will vary according to the location of the reading.
SurgiTel’s patented true color technology has been used for many years and offered the best color accuracy and eye safety. Recently, some Chinese companies have been imitating SurgiTel’s true color beam-forming optics which may infringe some of SurgiTel’s patents, and have started to sell these optics to U.S. companies.
Recently, Orascoptic introduced their new LED headlights using new beam-forming optics and published paid marketing messages in Dental Product Shopper magazine and on their website. Reading Orascoptic’s marketing claims I found that Orascoptic’s marketing claims are not likely completely truthful. So, I would like to review claims, and discuss LED headlight technologies, and provide simple guidelines for selecting a proper LED headlight.
First claim: Orascoptic’s breakthrough “TruColor” technology enables headlights to render colors much closer to natural sunlight than legacy headlights. Orascoptic claims that this technology is a first and only.
Comment: SurgiTel introduced the first true color, beam-forming technology many years ago. Orascoptic’s lights may use a beam-forming optics similar to SurgiTel’s patented beam-forming optics. It is noted that we have not evaluated the exact design of this new Orascoptic optics yet, but their description implies that they use achromatic, beam-forming optics.
In 2012 the CR Foundation evaluated LED headlights and found that SurgiTel’s neutral LED headlights offer the best color accuracy and the safest to eyes.1,3 At that time, Orascoptic sales representatives said that blue lights were superior because of the bright appearance. Now, Orascoptic is admitting blue light is dangerous and that their all previous LED headlights, which did not use their newest, trademarked marketing terms were not superior after all.
Second claim: All other loupe-mounted LED headlights exhibit CRI values in the low 70s at best.
Comment: This claim may be applied to all other loupe-mounted LED headlights, excluding SurgiTel’s LED lights. SurgiTel is the first company that has used true color beam-forming optics technology which can preserve CRIs of LED chips used.
Third claim: Orascoptic’s new LED headlights were tested to ensure compliance with blue light testing standards.
Comment: Since the blue light of LED headlights can damage eyes,4-13 SurgiTel LED headlights have been designed to minimize risk. Orascoptic claimed that they tested their lights according to “blue light testing standards for LED headlights” to ensure the safety of users’ eyes. But there are no blue light testing standards for LED headlights. They may have used blue light testing standards for electronic display or room illumination. However, that would be misrepresentative because clinical headlights are much brighter and concentrated.
The Orascoptic website14 shows that the color temperature of Orascoptic LED chips are 6,500K which is the coolest LED among white light LED chips (warm: 3,000K, neural 4,000K, cool: 5,700K, and extreme cool: 6,500K) used for LED headlights (Figure 2).
The SurgiTel brand-neutral LED is the best available light for eye safety and color accuracy for most clinical procedures. This is because the elements of the light spectrum (aka the mix of light color which creates the beam) is balanced as shown in Figure 2. This means the eye reacts appropriately and looking at the light will not only feel comfortable but also reduces exposure to dangerous blue light. The blue light of LED chips used by Orascoptic is about 2x stronger than the green-magenta. Will this ultra-cool LED light really be safe to our eyes?
The CR Foundation’s measurements of Orascoptic wireless LED lights showed that the Orascoptic Spark is 9,800K and the Orascoptic XV1 is 10,000K.12 LED lights with Kelvin temperature higher than 6,000 are considered to have too strong of blue light. Dental professionals are using orange filters to protect their eyes when they use curing lights which are at this level. As shown in Figure 2, the color temperature increases, the intensity of blue light increases.
Simple Guidelines to Find Good LED Headlights
Color accuracy, good color rendering, and eye safety from the blue light should all be of top concern when considering an LED headlight.
Here are a few tips for evaluating an LED headlight:
- Check the beam uniformity at various distances.
- The beam should be uniform and consistent in color at various distances.
- The beam should not have a visible blue color tint. This is important for your eye safety.
- To evaluate the lighting of the LED, use it on your hand or an anatomical model, not white paper. To compare lights, you should compare side by side when possible. Note that another reference illumination can be used.
- The beam should create color images closer to color images under room lighting.
- Details of anatomical features should be clearly seen under the illumination of LED headlights. Note that extreme cool LED lights may look good with a white paper but may wash out anatomical details and have a blue tint.
It is noted again that CRI or CCT of beam of LED headlights will be different from those of LED chips used if beam forming optics is not true to color. The key technology for LED headlights is the true color beam-forming, achromatic optics. Other manufacturers are trying to imitate the SurgiTel true color LED lights, but still, SurgiTel LED headlights are the lightest weight, have the best color accuracy, and the safest to your eyes. If you want the best color accuracy, the safest to your eyes, and comfortability, your decision is an easy one. SurgiTel offers it all!
- Clinicians Report, “Smaller and Lighter LED Headlamps”, A Publication of CR Foundation, April 2012, www.CliniciansReport.org.
- Price Curing Lab. “The Blue Light Hazard in Medicine and Dentistry.” YouTube. Price Curing Lab, 22 July 2012. Web. 24 Apr. 2015. .
- Clinicians Report, “Is your LED headlamps damaging your eyes?”, A Publication of CR Foundation, March 2013, www.CliniciansReport.org
- Stamatacos, C and Harrison, JL, “The potential ocular hazards of LED dental illumination applications”, continuing Education Article – Exam #51, J Tennessee Dent. Assoc. (Publication date: Fall/Winter 2013, Expiration Date: Fall/ Winter 2016)
- Sparrow RJ, et al. “The lipofuscin fluorophore A2E mediates blue-light induced damage to retinal pigmented epithelial cells”, Invest Ophthalmology Vis Sci 2000; 41:1981-9
- Delcourt C, et al. “Light exposures and the risk of agerelated macular degeneration”. Arch Ophthalmology 2001; 119:1463-8
- Sparrow RJ, et al. “DNA is a target of the photodynamic effects elicited in A2E-laden RPE by blue-light illumination”. Invest Ophthalmology Vis Sci 2003; 44:2245-51
- Algvere, PV, Marshall J, Seregard S. “Age-related maculopathy and the impact of blue light hazard”. Acta Ophthalmol Scand 2006; 84 (1): 4-15.
- “Overview of LED Product Safety, A European Perspective, Photobiological Safety of Lamps”, May 2009 Bentham Company: www.bentham.co.uk (technical guides/pdf)
- “Optical safety of LED lighting. (CELMA) European Lamp Companies”; 2011. “http://www.celma.org/archives/ temp/CELMAELC_LED_WG(SM)011_ELC_CELMA_ position_paper_optical_safety_LED_lighting_Final_1st_ Edition_July2011.pdf”.
- Cruickshanks KJ, et al. “Sunlight an 5-year incidence of early age-related maculopathy: the Beaver Dam Eye Study”. Arch Opthalmology 2011;119: 246-50
- Clinicians Report, “Cordless LED Headlamps: A Bright Idea?, A Publication of CR Foundation, May, 2017, www.CliniciansReport.org. For the full report, go to: www.surgitel.com/clinicians-report/
- Chang, BJ, “Is Your LED Headlight Type Safe for Your Eyes?” ErgoPractice News, November 2018. https://surgitel.com/is-your-led-headlight-type-safe-for-your-eyes
- “Headlights”. Orascoptic, Orascoptic, www.orascoptic.com/products/headlights.