Illuminating Key Considerations for Loupes

As our knowledge about ergonomics has grown over the years, we have sought ways to see into patients' mouths effectively without wrecking our bodies. Loupes have become the most impactful tool for the task. Proper magnification helps the clinician keep their body within a specified distance from the mouth, and loupes, when utilized correctly, significantly reduce workplace injury.

All loupes are not the same, however. Quality can vary based on the manufacturer, and customization is key. There are different types of loupes to choose from. Galilean loupes typically have lower levels of magnification (2.0x to 3.0x) but wider fields of view, so they can be ideal for first-time users. Traditional through-the-lens (TTL) loupes provide magnification of 3.0x and higher. Flip-up loupes provide more adjustability, which can be helpful when talking to patients, but often they are not as sturdy. Prismatic loupes, meanwhile, keep the head in a neutral posture via a series of deflections and angles that allow us to look forward with our eyes but see what is directly below us.

Traditional loupes place the head in 20° flexion with a 35° to 40° declination angle. The body's spinal erector, upper trapezius, levator scapulae, scaline, and sternocleidomastoid muscles all engage to hold up the head. Depressors of the eyes are also taxed. Based on all of this, while traditional loupes are better than no loupes at all, it is the opinion of the author that a 20° flexion still is not safe. With prismatic loupes available that can reduce that flexion below 10°, combined with the knowledge we now have about ergonomics, we should be taking advantage of this opportunity to take better care of our bodies.

Prismatic loupes do require higher magnification because of the longer working distance, which narrows the field of view. Anything higher than 3.5x will not show the entire mouth at one time, so care should be taken to balance those needs.

Everyone has different facial features, so various measurements should be factored into the fabrication of loupes for each individual user. Whether the frames are plastic, titanium, sport, or classic, the most important thing is that they properly fit your facial features. Cheekbone position, eye socket shape and depth, ear position, and head size are all important factors to take into consideration. For example, someone with high cheekbones might be well suited for sport frames because of how a higher outside lens will go around higher cheekbones; the lens should touch or almost touch the cheekbone, to prevent debris from getting underneath. Do not assume that someone with the same vision prescription has the same pupillary distance or socket depth.

Because facial features vary by individual, in-person measurement is important. The author recommends purchasing loupes from a company that can send a representative to take your measurements, or one that can take your measurements at a tradeshow.

Several factors can impact the quality of the magnification itself. Optical-grade glass-as opposed to plastic oculars-provides the best light and perception. Brightness is important as well; most loupes range between 21,000 and 60,000 lx (or lm/m2), and higher levels typically are preferable. Color rendering index (CRI) is also important; a CRI of 90 or higher provides the most realistic, real-life view of what you are looking at.

Weight is yet another important factor. The less weight placed on the face, the better. For this reason, the author recommends corded illumination rather than cordless; there are options for batteries that clip onto the shoulder or scrubs. Battery life can range from approximately 3 hours for smaller batteries to multiple days for larger ones; this is simply a matter of preference.

Loupes are not the only way to optimize ergonomics, but they are probably the most important. Like so many of the tools that we use in clinical practice, what is best for one person might not be best for another. Each dental hygienist should do due diligence on the various options available on the market and make the best decision based on their own preferences and needs.