ErgoPractice News – September 2018
Choosing the right loupe and light can be a daunting and confusing task, especially because different sources will be disseminating different information. There are a number of myths that influence buyers, particularly students when making these purchases. Since everyone may agree that high-quality optics and precision alignment are essential requirements, in this issue of ErgoPractice News we will clarify three of the most common loupe and light myths.
1. Selecting Magnification Power: Does 2.5x Work for Everyone?
Over the last decade, 2.5x loupes have become an integral part of the practice of surgery and dentistry, especially for students and dental hygienists. When it comes to important tools like loupes and headlights that will be used everyday students often seek advice from mentors and classmates, and it’s easy to consider what’s best for them best for you too. However, these products need to be custom for you and your work. As such, the 2.5x standard has come into question.
One of the main factors to consider when looking for loupes is the way in which your working distance changes perceived magnification – this is called the Working Distance Effect. Two clinicians working with a significantly different working distance will need different magnification power to see the same level of detail (Figure 1).1
We know that it is easy to “magnify” an object simply by bringing it closer to your eyes (poor ergonomics have become an issue for clinicians because they tend to bend closer to their subjects to see better). The same principle applies to clinical magnification. Take for example two clinicians standing at a table, one who is 5’2” and one who is 6’2”. Even without loupes, the shorter clinician sees everything on the table in greater detail just because they are closer.2
Because greater working distances require greater magnification to see the same level of detail, students looking for loupes must consider their working distance an important factor. A working distance of 20 inches is 25% longer than a working distance of 16 inches, meaning the magnification required to see the same level of detail should be at least 25% greater. To see your best, you must be willing to choose a magnification level that may be different than the standard your classmates work with.
SurgiTel offers more magnification options than any other loupe company on the market, from 2.5x to 8.0x. With these options, every student can find the right loupe for their needs. Using SurgiTel loupes, clinicians are able to further adjust the working distance and magnification of loupes using working distance caps.
2. How Can You Identify Ergonomic Loupes?
In recent years clinical ergonomics has become a valued and important topic for dental, medical, and veterinary professionals. Many loupe companies have begun to market their loupes as ergonomic, even if they really aren’t. The easiest way to do this is by claiming to have a large declination angle. So why do we still encounter clinicians working with “large declination angle” loupes who are suffering from chronic neck pain?
Declination angle is the measurement of how well loupes help the user look down with their eyes, rather than by bending their head and neck.3 Many loupe companies claim their loupes have large declination angles, meaning they help the clinician reduce the degree of head tilt required to see out of the oculars. This measurement can be done in various ways to present a higher declination angle than the loupe actually has, and companies can choose the measurement that gives the greatest appearance of ergonomics in their products.
In order to get an accurate measure of the declination angle the user should we wearing the loupes in question. The reference line should be the line that connects the corner of the eye and the top of the ear (Figure 2B). Most loupe companies use the temple arm as the reference line, which greatly increases the apparent declination angle (Figure 2A). Using this trick, clinicians and students are told they will receive loupes with a very large declination angle and in reality get loupes with poor ergonomics, exacerbating neck and back issues.4
The only true way to measure ergonomic posture is by looking at the head tilt. Loupes can be considered ergonomic if they allow the user to keep their head tilt at 25° or less.5, 6 Non-ergonomic posture contributes to a large percentage of the pain and injuries that clinicians experience throughout their career. An adult head weighs between 10 and 12 pounds, and tilting the head forward compounds the amount of pressure put on the neck.7 Non-ergonomic loupes that force you to tilt your head closer to 60° forward put about 60 pounds of pressure on the neck, which can cause serious neck and back injuries that may even end your career early.7
When evaluating loupes, focus on the posture you are able to achieve rather than the advertised declination angle.
3. True Requirements of LED Lighting
When clinicians try SurgiTel LED headlights at trade shows, I often see them immediately turn the brightness dial to the highest setting. LED users have been taught that brighter is better when it comes to clinical lighting, but this is not the case. In reality, looking at your subject with a too-bright LED can wash out details rather than illuminate them.
Safe and effective LED headlights should satisfy two qualities: beam uniformity and color balance (Figure 3). Headlights that meet both of these requirements not only allow you to see more details at various brightness levels, but are also safer for the eyes.
The technology behind SurgiTel’s patented LED headlights that allows them to have beam uniformity and balanced color is a multi-lens system that produces an achromatic beam. This clearly defined and even light spot has no bright central spot and diminishes glare, both of which wash out details of your subject.
An achromatic beam produces a color-balanced light, which makes work easier and produces better outcomes. Color balanced beams are also safer – a lower color temperature like that of SurgiTel LEDs (3,900K) puts less strain on the eyes, especially after looking at it for long stretches of the day. Other LEDs on the market have much higher color temperatures (up to 10,000K) which peak in the blue-light spectrum (Figure 4).8 This hazardous peak can cause serious issues like retinal damage and macular degeneration.9
Choose a headlight that allows you to work better and safer, without relying on the brightest setting.
Vision and Ergonomics at Work
Discover how SurgiTel’s ergonomic product line can help you see better and work safer. For more information, or to try it in person, contact your local representative at www.SurgiTel.com/myrep.
- Chang, BJ. How to Determine Magnification Power of Backup or Replacement Loupes, ErgoPractice News, November 2017.
- Chang, BJ. Should You Use the Same Loupes as Your Associate? ErgoPractice News, March 2016.
- Valachi, B. Practice dentistry pain-free, Posturedontics Press, Portland, OR, 2008. www.posturedontics.com
- Chang, BJ. Demystifying Declination Angle, ErgoPractice News, July 2016.
- Rucker, LM. Surgical telescopes: posture maker or posture breaker? In, Murphy D, ed, Ergonomics and the dental care worker. Am Public Health Assoc, Washington DC, 1998: 191-216.
- Pulat, BM. Fundamentals of Industrial Ergonomics, Chapter 7: 177. Prospect Heights, Illinois: Waveland Press, Inc., 1992.
- Sullivan, Laura. “Keep Your Head Up: ‘Text Neck’ Takes A Toll On The Spine.” NPR, 2014. https://www.npr.org/sections/thetwoway/2014/11/20/365473750/keep-your-headup-text-neck-can-take-a-toll-on-the-spine.
- Clinicians Report, Cordless LED Headlamps: A Bright Idea?, A Publication of CR Foundation, May 2017, www.cliniciansreport.org.
- Stamatacos C, Harrison J, The Possible Ocular Hazards of LED Dental Illumination Applications. Journal of the Tennessee Dental Association, Vol. 93 No. 2, 2013.