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Demystifying LED Headlights: 7 Questions and Answers

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ErgoPractice News – April 2015

The largest dental industry event in the world, the International Dental Show (IDS), takes place in Cologne, Germany every two years. SurgiTel visited and received many questions from clinicians about loupe and light technology. Last month we shared the most common questions about magnification, with answers. This month we will share the most common questions and answers about LED headlights.

Lighting and Working Environment

LED headlights should meet two conditions: 1) They should be safe for the users’ eyes1-4 and 2) they should provide users with the best image.4-6 To be eye-safe, LED beams should not have a dispersed (separated) blue light spectrum (Figure 1). And for the best color accuracy, the Blue/Green/Red colors should be balanced. Unfortunately, most manufacturers do not use safe and accurate LED’s.

The purpose of LED headlights is to help the clinician see and work better. Thus the designs of LED Headlights should consider how the eye reacts to light. Color accuracy and uniform image contrast are required for helping the clinician see the details of anatomical features. For our eyes to see the best, the LED technology must meet several requirements.

For the eyes to see target details, LED headlights must be designed for optimum brightness. The question is what is the optimum brightness? We do not want the image too dim or we will be straining to see, but we also do not want the image too bright or detail will be washed out. Today there rarely is any headlight too dim; it only appears dim as the surrounding environment is overly bright. Can you imagine using a desk lamp outside during the day? It probably would not appear to work well. But indoors it works wonderfully. The lamp actually works the same in both environments but the target-to-background ratio is different. For any light to work best it should be three times as bright as the surrounding environment.3 Is your headlight three times as bright as the combined light coming from your room lights, overhead lights, and all light coming from the windows, hallways, et cetera? If not, simply dim or turn off the other lights in the room. Suddenly you may find your headlight too bright! And this is why SurgiTel LED Headlights feature a brightness adjustment knob, to maximize the level of detail.

LED Headlights: Core Requirements

At IDS some clinicians were attempting to determine light quality based on brightness, believing that the higher the brightness the higher the quality. But most brand LED headlights to meet and exceed the brightness requirement. So how can we judge light quality? We propose four basic requirements:

First Requirement: The beam should be achromatic (no color separation) for the best color accuracy.4 Also the achromatic beam (balanced blue light) is the safest to the eyes.2,4

Second Requirement: There is no change of beam color or pattern throughout the working distance range. If the pattern of the beam changes as the working distance changes, the color of objects will distort and users may not perceive accurate colors.

Third Requirement: The beam should be uniform. If the beam is not uniform over the field-of-view, the eye can never adjust well. The contrast is distorted and, again, users may have trouble seeing right color. Figure 1 shows achromatic beam versus dispersed beam patterns.

Fourth Requirement: Lights should be light-weight. Wearing heavy headlights is distracting to the user. The user should be able to forget the headlight and be able to concentrate on their work.

Additional factors to be considered may include battery size and charge life, LED types and on/off switching methods.

Questions and Answers:

During our IDS visit, we noted several of the most asked questions about LED Headlights. Here are seven of the most common:

Question: “Are smaller batteries better?”
Answer: While smaller batteries may be lighter, this design may drastically reduce the duration of the charge life. You may find it more inconvenient to have your LED headlight lose charge in the middle of the day than a few more ounces of weight on a belt pack. Battery weight may be very important in designs where manufactures hope to create a “wireless” loupe. With the batteries on the user’s head, weight becomes a major issue and there is no choice but to reduce battery life. With the more popular belt battery pack design, however, weight need not be a major selection factor for LED headlights.

Question: “What LED type is the best for color accuracy?”
Answer: If color accuracy is important, for example during cosmetic procedures, neutral LED lights are the best.5,6

Question: “Why are cool LED lights better for surgical procedures?”
Answer: Cool LED lights have a significantly strong Blue spectrum band over Green/Red spectrum bands and can enhance certain features of organs such as veins.6

Question: “Why are SurgiTel’s LED headlights more expensive?”
Answer: Most traditional LED headlights use single-lens optical systems. Single-lens optical systems cannot generate uniform, achromatic beams. Therefore SurgiTel developed a precision multi-lens beam-forming optical system. SurgiTel’s patented achromatic optical systems use several precision lenses which require precision alignments and thus SurgiTel’s LED headlights are more expensive than traditionally designed LED headlights. However, they offer the best beam for color accuracy and image contrast. SurgiTel’s LED headlights allow you to do your very best work, safely.2,4

Question: “Why does SurgiTel not offer wireless LED headlights?”
Answer: SurgiTel considered several head-mounted concepts but, as previously mentioned, the design requires users to wear heavy batteries on their heads and has reduced battery life. SurgiTel cannot offer a design that does not function well for the user.

Question: “Why does SurgiTel not offer battery packs with push-button on/off switching?”
Answer: Push-button design was created to reduce the risk of cross-contamination but is not actually touch-free. Also when examining this option, we noticed lights may turn on and off accidentally.

Question: “How does SurgiTel’s no-touch Eclipse Light work?”
Answer: Eclipse switching technology uses an advanced IR proximity sensor. The light can be turned on and off by the simple motion of the hand and is touch-free. This technology will allow users to avoid cross-contamination effectively.7

We hope these answers have provided you new insight into LED Headlight technology. If you or someone you know has any questions about advances in LED Headlights, contact your local representative at surgitel.com/myrep.

 

References:
  1. Price Curing Lab. “The Blue Light Hazard in Medicine and Dentistry.” YouTube. Price Curing Lab, 22 July 2012. Web. 24 Apr. 2015. <https://youtu.be/VfCmL4Kz2iw>.
  2. Clinicians Report, Is your LED headlamps damaging your eyes?, A Publication of CR Foundation, March 2013, www.CliniciansReport.org.
  3. 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)
  4. Chang, BJ, Advances in SurgiTel Headlights: Design Considerations of LED headlights for Color Accuracy and Eye Safety, ErgoPractice News, March 2014; https://surgitel.com/advances-in-surgitel-headlights-design-considerations-of-led-headlights-for-color-accuracy-and-eye-safety/
  5. Chang, BJ, Fundamentals of clinical illumination and LED technology, ErgoPractice News, November 2013; https://surgitel.com/fundamentals-of-clinical-illumination-and-led-technology/
  6. Clinicians Report, Smaller and lighter LED headlamps, A Publication of CR Foundation, April 2012, www.CliniciansReport.org.
  7. Clinicians Report, Infection Control Challengers with Dental Loupes and Headlights, A Publication of CR Foundation, February 2015, www.CliniciansReport.org.