In the loop about surgical loupes

e-news from Josie Blake…

We recently attended the ACE 2016 conference in Niagara Falls. Topics ranged from specific research on twisting the back, to sit-stand workstations, to training in the healthcare field. One presentation on dental professionals got me thinking about my recent trip to the dentist, and made me wish I had another appointment soon, just so I could ask about what I learned. (Since when does anyone want to go to the dentist more often than they have to?)

The presentation was about surgical loupes (see example here: These are magnification devices worn by dental and medical professionals that allow the clinician to observe structures which are not easily visible to the naked eye. Your dentist might not use these, but they are becoming mandatory for students, so usage will increase over time. New “ergonomic” loupes have been designed with a “declination angle” which encourages the clinician to sit more upright, with his/her head balanced over the shoulders. S/he can look down through the lenses, rather than lean forward, or bend the neck, to see into the patient’s mouth. This angle may be adjustable, so a clinician can adjust the lenses so that s/he can work with the head up, and the arms relaxed. Some lenses also incorporate prisms which improve the neck posture even further. Some clinicians report that it feels unnatural to sit upright while looking at something that would normally require forward leaning; however, those who have experienced neck, upper back, and shoulder pain embrace the change! the mannequin graphic above shows what we consider to be a neutral balanced posture, on the left. The middle graphic represents the head and neck posture used with “regular” loupes, and the right graphic shows the posture used to view through “ergo” loupes (with a declination angle).

The research I learned about at the conference specifically focused on clinicians in the dental field, wearing surgical loupes with the magnification lens in “co-axial misalignment”. This means that the magnified image through the instrument is not aligned with the unmagnified image. The presentation showed an example of the sharp, pointy instrument the clinicians use to clean your teeth entering the loupe field of vision lower or higher than the actual instrument. In this study, they found that at 4/5 dental professionals worked with this misalignment!

The presentation also showed another concern – “chromatic aberrations”; meaning that the magnifying lenses are unable to bring all of the colours into the same focal plane, resulting in the clinician experiencing bright sparks of different colours in the magnifying field.

Besides the risk of poking your patient in the lip, cheek, gum or tongue, the research also identified some ergonomics concerns associated with misaligned loupes:

  • The clinician purposefully aims high or aim low, or the clinician may need to constantly move the neck “up and down” to visually locate or correctly align the instrument. This can result in repetitive, awkward movements, postures of the neck, or of the upper limbs if the neck starts to get sore! Alternatively, the clinician may “crane” or twist the neck in a static posture.
  • Colour aberrations may cause eye strain (as well as nausea and compromised clinical decision making).

So, how have dental professionals been working like this for so long? Well, wearing the loupes does take an adjustment period. However, according to this study, the adjustment period is the most significant disadvantage of using surgical loupes, and some people have difficulty adapting, resulting in a decision to not use them at all.

So, if the coaxial alignment could be adjusted to fit the user every time, would these problems go away? No one has been able to figure that out yet, but the author of this study hopes that her research will prompt healthcare professionals to make more informed decisions when choosing and fitting their equipment. She also hopes that surgical loupes manufacturers will use this information to ensure all users are able to properly align their loupes. This may encourage more dental professionals (and other professions using this type of magnification system, e.g. surgeons, jewelers, micro-engineers, etc.), to experience the other benefits of these devices.

If you’d like to read more and see photos of co-axial misalignment, the full paper is available here:

Are you in a profession where you use loupes? Do you know if your surgical loupes are coaxially aligned? Or do you know someone who uses them that may not be aware of this adjustment?

Even more exciting…can you think of an occupation or task outside this field, that would benefit from the use of surgical loupes?

Let us and other readers know your experience by commenting below!

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