Rheumatology Polarization
Installing and Operating Instructions
Introduction:
Polarized light microscopy is used for observation of crystalline and mineral specimens, because of their optically
anisotropic character. Contrast occurs due to polarized light interacting with the birefringence (double refraction) of
crystals. The
polarizer
is a two-stage filter assembly (polarizing lens and red compensator lens) that must be
positioned in the light path below the specimen, and the
analyzer
(smaller polarizing lens) must be positioned above
the specimen and objectives and beneath the head.
When the two filters are aligned parallel with each other, the polarized light path is transmitted through both filters and
the field will be at its brightest, but when the polarizer (lower) is turned 90 degrees the light is extinguished. At this
cross-polarized setting anisotropic crystals will appear to glow against a relative dark background, and when the red
compensator lens is used the birefringent material will show as either blue or yellow against a red background
depending on the material’s orientation.
Polarization is an investigative tool used to distinguish different types of arthritis. It has many other applica
tions as well.
Features:
The polarization kit is only available on
M-Series LabScopes
. It includes two parts which are easily installed in less
than 1 minute. These quality filters combined with the bright illumination and PLAN optics of the
M-Series LabScopes
produce clear contrast and high resolution images.
Installation and Setup:
Remove the head of your
M-Series LabScope
.
Install the
analyzer
(the smaller filter...about the diameter of a quarter) by placing it into the small opening
inside the head mounting circle on the microscope. Make sure the small screw on the side of the filter fits
into the slot inside the opening. You may leave the
analyzer
in place for brightfield use if you choose.
Re-install your head.
Remove the
red compensator lens
(clear lens with plastic handle) from the lower polarizer assembly by
simply pulling it out of the housing. Set it aside.
Install the
polarizer
by loosening the thumb screw and placing it over the base illuminator lens. Turn on
the microscope, select the 10x or 40x objective, and look through the eyepieces to view the
light field. Turn the
polarizer
90 degrees either direction to achieve the darkest light setting
and then tighten the screw. Make sure that the slot for the
red compensator lens
is not
facing to the rear.
Using a sample specimen slide, focus on an active crystal which should be glowing and then slide the
red
compensator lens
into place over the
polarizer
.
Rotate the
red compensator lens
to achieve a red background. Crystals will show either positive or
negative birefringence, by turning either yellow or blue in relation to their orientation. By rotating the
red
compensator lens
90 degrees, you will notice the color of the crystals change from blue to yellow, or
yellow to blue.
Use positive test slides to create a protocol for diagnosing gouty or pseudo gouty arthritis. Crystals
should be identified by both their morphology and their direction of birefringence.
When finished, remove the
polarizer
and store carefully in a dust free container.
Care and maintenance:
Clean the filters very delicately with lens paper and lens cleaning solution only if dirty.
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