- Mikko Jokikokko
SurgiTel’s Compact Prism Loupes vs Designs for Vision’s Panoramic Loupes
Updated: Jan 5
December 22, 2021

Introduction
Many US customers and international distributors have reported that sales reps of Designs for Vision (DFV) are claiming that field sizes of their new patented “Panoramic Loupes (3.5x and 4.5x)” are double of other expanded field loupes of its competitors. This claim is not true, as field sizes of DFV’s new Panoramic 3.5x and 4.5x loupes are double the field sizes of their classic style 3.5x and 4.5x loupes.
Figure 1 shows SurgiTel’s Compact Prism loupes and DFV’s Panoramic loupes. Figure 2a shows magnified fields of DFV’s various loupes and Figure 2b shows magnified fields of SurgiTel’s Compact Prism loupes (3.5x/EVK350) and (4.5x/EVK450) against magnified fields of DFV’s Panoramic loupes (3.5x and 4.5x). As shown on the right of Figure 2, field sizes of SurgiTel’s patented “Compact Prism Loupes (3.5x and 4.5x)” are larger than field sizes of DFV’s patented “Panoramic Loupes (3.5x and 4.5x). SurgiTel’s Compact Prism loupes offer other practical advantages over DFV’s Panoramic Loupes. Before we discuss advantages of SurgiTel’s Compact Prism Loupes over DFV’s Panoramic Loupes, we will review types of loupes and marketing names of loupes created by DFV.

Figure 1: Left is SurgiTel’s Compact Prism Loupes and the right is DFV’s Panoramic Loupes.

Figure 2: (2a), Magnified fields of various Designs for Vision’s loupes, (2b), Magnified field of
SurgiTel’s Compact Prism loupes are added (green).
Types of Loupes
Loupes can be classified into two types based on optical designs. Figure 3 shows two
loupe optics types. The 1 type is Galilean loupes which use a telescope optics design
invented by Galileo who was an Italian astronomer and physicist. Galilean telescopes
consist of two optics groups — positive objective optics and negative eye-lens optics. The
2 type is Keplerian loupes which use a telescope optics design invented by Kepler who
was a German astronomer and mathematician. Keplerian telescopes consist of two
positive optics groups and a prism between two optics groups which rotates the image.
The main functional difference is that Keplerian telescopes can offer a larger magnified
field than Galilean telescopes. Galilean optical designs are used for low magnification
power loupes (2.0x to 3.0x) because the field size of higher power Galilean telescopes is
very small. Keplerian designs are used for high magnification power loupes (3.5x and
higher).

Figure 3: Optics of Galilean Loupes and Keplerian (or Prism) Loupes.
Names Created for Marketing by DFV
Let’s review names of loupes created by DFV for their marketing purpose such as
“Standard Field Surgical Telescopes,” “Expanded Field Surgical Telescopes or EF
Surgical Telescopes,” and “Panoramic Loupes.” DFV has classified their loupes (or
surgical telescopes) into three types based on field sizes. Standard Field Surgical
Telescopes are Galilean Loupes which offers the smallest field size. Expanded Field (or
EF) Surgical Telescopes are Keplerian (or Prism) Loupes which offer larger fields than
Standard Field Surgical Telescopes (Galilean Loupes). DFV might recognize that the field
size of SurgiTel’s patented Compact Prism loupes is significantly larger field than their
classic style expanded field loupes. Thus, DFV designed new Keplerian loupes which
offer similar fields offered by SurgiTel’s Compact Prism loupes. Because DFV cannot use
SurgiTel’s patented optical design concepts, DFV has used a more complex design which
requires more optical elements. DFV created a new marketing name of “Panoramic
Loupes” for their new Keplerian loupes, which offers field sizes similar to field sizes of
SurgiTel’s Compact Prism loupes.
Practical Advantages of SurgiTel Compact Loupes
SurgiTel’s patented Compact Prism loupes offer circular fields and DFV’s patented
Panoramic (prism) loupes offer rectangular fields according to the diagram which shows
field shapes, but viewable field sizes are similar. Let’s review practical advantages of
SurgiTel’s Compact Prism loupes over DFV’s Panoramic loupes.
1. Superior ergonomics: Using patented frames and manufacturing technologies,
SurgiTel can offer truly ergonomic loupes to any clinician, helping prevent or
alleviate the neck pain.
2. More frame choices: Oakley Radar frames and SurgiTel titanium frames
(patented) are available for compact prism loupes. These frames are very stable for
high magnification loupes and offer good eye protection as well as provide
maximum comfort.
3. Custom nose pads for maximum comfort to wear: Single nose pads do not fit all
nose types. SurgiTel offers several patented custom nose pad options for various
nose types.
4. Lighter weight: The weight of DFV’s 4.5x Panoramic loupes is about 130g and the
weight of SurgiTel’s 4.5x Compact Prism loupes is approximately 85g. The weight of
Panoramic loupes is approximately 50% heavier than Compact prism loupes.
5. TTL (Through-The-Lens) or FLM (Front-Lens-mounted) mounting options:
TTL offers larger fields, but FLM offers more flexibility to users by allowing users to
customize their viewing angle for various cases.
6. Optimum field size with SurgiTel’s custom nose pads: If you want to optimize
the field size, SurgiTel’s custom nose pads allow you to optimize the field size by
adjusting the space between loupe optics and eyes.
7. Easy adjustment of working distance with working distance caps: If you want
to create different working distances for different patients or procedures, you can
adjust working distance using interchangeable working distance caps.
8. Restoring the working distance that is increased due to aging eyes with
interchangeable working distance caps: Aging eyes may require reading
glasses. The power of reading glasses can rapidly change from 0.25 diopter (age
40 to 45) to 2.5 diopter (age 55 to 60). With aging, you might notice that the working
distance of loupes has increased. If you want to restore the original working
distance of loupes, you must add reading prescription to loupe optics. Adding a
reading prescription to most brand TTL loupes must be done by manufacturers –
which includes lost time and updating fees. However, the working distance of
SurgiTel’s TTL loupes can be easily changed by replacing the current working
distance caps. Therefore, there is no loss of time and no updating fee. With
SurgiTel’s TTL prism loupes, you can save thousands of dollars restoring the
working distance of loupes.
9. Increasing the effective magnification power of loupes with interchangeable
working distance caps: Eyes can see better by getting closer to objects because
the image projected onto the retina becomes larger as the object distance
decreases. Loupes just magnify the image projected onto the retina. If you deduce
the working distance of SurgiTel’s prism loupes with interchangeable working
distance caps, you can increase your visual acuity. If you decrease the working
distance by 20%, you can see 20% better with line, 36% better with area, and about
50% better with 3D objects. SurgiTel’s prism loupes can be used as multi-vision
loupes.
Why SurgiTel is Your Partner for Your Vision-Aid Products
The founding mission of SurgiTel has been providing clinicians with truly ergonomic,
posture-safe loupes and eye-safe LED headlights. During the last thirty years, SurgiTel
introduced many world-first vision-aid products based on patented concepts; including customizable FLM (Front-Lens-Mounted) loupes, ergonomic frames, truly ergonomic TTL
(Through-The-Lens) loupes, true-color LED beam-forming optics which allows SurgiTel to
offer eye-safe LED headlights with the best color accuracy, LED lights with no-touch
switching, multi-vision loupes with interchangeable working distance caps,
interchangeable custom nose pad systems, and loupe-mountable digital cameras
(SurgiCam HD). SurgiTel offers unique benefits which may not be available with other
brands as follows:
1. SurgiTel offers the most magnification options (2.5x to 10x)
2. SurgiTel offers all magnification loupes with either FLM style or TTL style
3. SurgiTel offers the most LED light options (warm, neutral, and cool) with various
models (wired, wireless, and no-touch switching)
4. SurgiTel offers truly ergonomic loupes to any clinicians with various nose types
which offer truly ergonomic benefits over deflection loupes.
5. SurgiTel offers a free evaluation service — posture analysis with your current loupes
and potential blue light hazard with your current LED lights
SurgiTel’s free evaluation service can help evaluate your working posture and avoid the
potential blue light hazard of various cool brands of LED lights.
References:
1. Reality, Outlook of Panoramic Loupes (Vision Aid – Magnification Loupes), 2019.
Note that this was a preview and did not compare these loupes with other brand
loupes.
2. American Optometric Association, Adult Vision; 41-60 years of age
3. Sun F, et al, Changes in Accommodation with Age: Static and Dynamic, American
Journal of Optometry & Physiological Optics, 1998, Vol. 65, No. 6, pp 492-498