Evolution of Loupes and Unique Advantages of SurgiTel Ergonomic FLM

ErgoPractice News – April 2021

Some of the clinicians who have used SurgiTel FLM (front-lens-mounted) loupes do not like TTL (through-the-lens) loupes because the magnified field size of TTL loupes is too large (more than needed) and the blind spot (or called scotoma) of TTL loupes between the peripheral visual field and the magnified vision field is large (Figure 1). These clinicians want to see only operating objects (for example, only teeth inside the mouth but not the nose). SurgiTel FLM loupes can offer several unique advantages over other FLM loupes and TTL loupes. We will review these unique advantages here.

Figure 1: Diagram of Magnified Vision Field, Blind Spot (Scotoma), and Peripheral.

Evolution of Loupes

The purpose of early loupes was to help low vision patients read. In the early 1940s, surgeons found that loupes were helpful to see fine anatomical features of their operating sites. In the early 1980s, dental professionals started to use loupes. Today loupes have become essential instruments for the practice of dentistry and surgery.

Loupes can be classified into two styles according to mounting methods: FLM and TTL styles. FLM loupes can be divided into two kinds: the first kind of FLM loupes without the vertical adjustment which have a fixed declination angle and the second kind with the vertical adjustment which can allow users to adjust the declination angle. Early 1990s SurgiTel invented the second kind of FLM loupes which are called ergonomically customizable FLM loupes.¹

Also, TTL loupes can be divided into two kinds. The first kind of TTL loupes with small declination angles (about 22 degrees) were designed to provide users with magnified vision. The second kind of TTL loupes with true custom declination angles (up to 50 degrees) which are called ergonomic TTL loupes were designed not only to provide users with magnified vision but also to help users work with the safe neck posture. SurgiTel introduced the second kind of TTL loupes by inventing ergo frames and special manufacturing technologies.²

Issues Related to the First Kind FLM Loupes

The declination angle of these loupes is small and thus the use of this kind of loupes can create chronic neck pain. Since mounting rack-arm assemblies are not stable, the lightweight, first kind FLM loupes are limited to 2x to 3.0x. There are high-power FLM loupes, but they are very heavy. To eliminate drawbacks of first kind FLM loupes, SurgiTel invented lightweight, stable rack-arm assemblies which can offer up to 10x loupes.

Issues Related to TTL Loupes and SurgiTel’s Solutions

TTL loupes have become very popular because of their simplicity. But there are several issues with TTL loupes. The main issue with the first kind, non-ergonomic TTL loupes with a small declination angle is that the use of these non-ergonomic TTL loupes for an extended period (of time) can create chronic neck pain or injury, but users cannot recognize this problem for many years until their neck pain becomes serious.

There are other issues such as fogging, touching eyelashes, a large blind spot (or scotoma) between peripheral vision field and magnified vision field, and an expensive fee for updating prescription (Rx).

To eliminate these issues of first kind TTL loupes, SurgiTel invented ergo frames, ergo-fit nose pads, interchangeable working distance caps, and advanced manufacturing technologies to offer the second kind, truly ergonomic TTL loupes to every clinician.

Today SurgiTel can offer both ergonomic FLM loupes which allow users to customize the declination angle for the safe neck posture for various working positions and ergonomic TTL loupes which offer true custom declination angles for a safe neck posture.

Unique Advantages of SurgiTel Ergonomic FLM loupes

Unique advantages of SurgiTel ergonomic FLM loupes were possible with patented ergo frame with large pantoscopic angle (Figure 2) and patented lightweight stable rack-arms with precision alignment mechanism (Figure 3).

Figure 2: Pantoscoptic Tilt on Ergo Frame. (Patented)

Figure 3: FLM Loupes Mounting Rack Arm Fixture. (Patented)

Ergo frames allow SurgiTel FLM loupes to have the optimum field of view, lightweight stable rack-arms allow SurgiTel to offer lightweight prism FLM loupes (up to 10x), and erg fit nose pads can help distribute the weight of loupes over the entire surface of the nose evenly, allowing users to wear loupes comfortably (Figure 4). Also, the ergo fit nose pad system allows users to create the optimum space between eyes and glasses which optimizes the field size.

Figure 4: The Ergo-Fit Nose Pad System (Patent Pending) offers many combinations to create a custom fit.

Unique advantages of SurgiTel ergonomic FLM loupes which are not available with other FLM loupes and TTL loupes are:

Finding Optimum Declination Angle: It may be difficult for first-year dental or hygiene students to select ergonomically correct loupes. Since SurgiTel ergonomic FLM loupes allow students to try various custom declination angles, students can purchase SurgiTel FLM loupes and optimize their working posture by finding the optimum declination angle. If they want, they can exchange SurgiTel FLM loupes with SurgiTel TTL loupes within the trial period.
Gradual Change of Working Posture: Clinicians who developed their chronic neck pain with the use of non-ergonomic TTL loupes for an extended period may want to eliminate their chronic neck pain by improving their working postures with ergonomic loupes, but often a radical change of working posture may not be easy. With SurgiTel ergonomic FLM loupes, clinicians can increase the declination angle gradually and find the optimum declination angle which gives them the best comfort. After they find their optimum declination angle, they can purchase a pair of TTL loupes if they want, keeping the FLM loupes as a backup pair of loupes
Wider Range of Working Distance Change with Working Distance Adjustment Caps: Since loupes with shorter working distance can allow users to see better because images projected into the retina is magnified as the working distance of loupes is shortened. Since SurgiTel offers working distance adjustment caps, users can use the same pair of loupes as multi-vision loupes by adjusting the working distance with working distance caps.But decreasing the working distance will require the change of ocular separation (Figure 5). Since the separation of oculars of TTL loupes is fixed, the working distance change of TTL loupes is limited to a couple of inches, but SurgiTel FLM loupes allow users to adjust the separation of oculars and thus the allowable working distance change with FLM loupes will be significantly longer than TTL loupes. Therefore, those who want to use their loupes as a multi-vision loupe may choose FLM style loupes.³

Diagram showing the adjustment of Interpupillary distance on an FLM changes the Working Distance

Figure 5: The Convergence Point on an FLM is adjustable for those who need to work at various working distances. The TTL Convergence Point is fixed and will cause an overlap at a longer or shorter working distance.

Easy Updating Prescription (Rx) of Eyeglasses: While updating prescription (Rx) with TTL loupes should be done with manufacturers, updating Rx with FLM loupes can cost significantly less because it doesn’t require additional remaking steps (cleaning, drilling, aligning, and gluing). Also updating Rx with FLM loupes can be done with any local optical shop.

Who Should Consider SurgiTel Ergonomic FLM Loupes?

SurgiTel FLM loupes can offer unique advantages over other FLM loupes and TTL loupes. Anyone interested in these unique advantages should try SurgiTel ergonomic FLM loupes.

Those who want to find the best working posture by finding an optimum declination angle.
Those who have developed chronic neck pain and want to gradually improve their working posture to eliminate their neck pain.
Those who have low nose bridges and want to reduce the blind spot (or scotoma). For these clinicians, the distance between eyes and optics of TTL loupes becomes too close to the eyes, resulting in a larger blind spot and their eyelashes may touch the optics of TTL loupes
Those who may have to perform procedures that require radically different working postures.

The main difference between FLM and TTL loupes is that the oculars of FLM loupes are mounted in front of eyeglasses and the oculars of TTL loupes are mounted into the eyeglasses lens.

Why Is SurgiTel the Best Custom Loupe Manufacturer?

SurgiTel was founded over 30 years ago to develop the best ergonomic loupes which help clinicians work safely. SurgiTel has invented key technologies needed for both custom FLM and TTL loupes which can allow us to fit any facial features.

Magnification models are available with both FLM and TTL styles:
- Micro-line loupes (2.5x – 4.5x)
- Compact-line loupes (2.5x – 4.5x)
- Prism Pro-line loupes (5.5x – 10.0x)
Ergo frames (Patented) for ergonomic TTL loupes at any custom declination angle
Lightweight, yet sturdy FLM mounting fixtures (Patented) which can be used with high power loupes
Interchangeable custom nose pads (ergo-fit nose pads) for various nose types (Patent Pending)
Eye safe LED headlights (Patented) which improve the performance of loupes

SurgiTel is the only company that offers ergonomically fitted loupes for all facial features in both FLM and TTL styles.

Special Offers to SurgiTel Customers and Their Friends and Family

As we keep improving and innovating, we hope you will continue to grow with us. As a “Thank You” we have special offers and discounts to returning customers and referred customers. Check with your local SurgiTel representative for more details.

To contact your local sales representative go to Find a Rep or call 1-800-959-0153.

References:

Shahhal, S, “Review of SurgiTel’s 6.5x FLM loupes,” Testimonial – Dr. Sami Shahhal, DDS | Cosmetic | General Dentist| SurgiTel. August 2019
Staniek, K, “What They Didn’t Teach Us in Dental School” – Finding Pain Relief with SurgiTel, Testimonial – Dr. Katherine Staniek, DMD | SurgiTel. August 2019
Chang, BJ, “Multiple Magnification Loupes: 1987 to Today,” ErgoPractice News. August 2017