loupe will focus. The working distance must be
equal to the distance from the loupe lens to the
top of your subject. Each loupe has a defined
working distance, but the working distance you
require will depend upon your height, posture
and table height. It is best to determine your
desired working distance, and then choose a set
of loupes that will meet your criteria.
or use the table below to get a rough idea.To
measure your working distance, sit or stand in
a comfortable position with your back straight.
Do not lean forward too much. Measure the dis-
tance from your eyes to the top of your subject.
Usually, your working distance will be close to
what is shown in the table below.
the loupes is the field of view. The longer the
working distance of a loupe, the greater its
field of view will be. Likewise, the lower the
magnification factor, the larger the field of view.
This tradeoff must be considered carefully when
choosing loupes. When using a Galilean loupe
the center of the image is clear, but the outer
rim of the image is blurred. The prism loupe
image is sharp to the very edge of the field of
view.
directly related to the working distance and
magnification factor. The depth of field is the
amount of depth that is in focus when viewing
the subject through the loupe. Greater depth of
surgical microscope, if desired.
eyes is your interpupillary distance. For the sake
of comfort when focusing, your loupes must
fit your eyes. You optometrist can give you an
exact measurement. WPI loupes are adjustable
so that you can set your loupes to an inter-pupil-
lary distance that suits you.
can see deeper into the subject
without repositioning. For greater
depth of field, choose a loupe
with a longer working distance
or a lower magnification factor.
through the loupe is determined
by the amount of magnification,
which is a personal preference.
Higher magnification provides a
larger image, but it also means a
reduced field of view and depth
of field. Generally speaking, for
simple surgical cases or for be-
ginners in training, 2.5x or 3.0x
magnification is sufficient. When
a more delicate or complicated
procedure is required, choose a
magnification factor of 3.5x to
4.5x. If you are working on a tiny
area or are conducting a micro-
surgery, chose a magnification
factor of 5.0x to 6.0x. Higher
of prescription lenses (installed by user's
ophthalmologist).