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Problems are listed numerically
with check points following. Follow these check points in order. A separate
section is devoted to correcting image defects and artifacts.
1) Illumination lamp does not
light:
-
Power switch is on.
-
Power saver function is
off. Not every camera has this. Check your manual.
-
Illumination light adjustment
(28) is in midrange or above.
-
Check fuses.
-
Check the light bulb to see
if it is burned out or not seated properly.
2) Flash lamp does not flash
:
-
Power switch is on.
-
Power saver function is
off. Not every camera has this. Check your manual.
-
Flash intensity control
(21,22) is not on NF (no flash).
-
Upper / Lower switch is set
for the particular camera being used.
-
Digital imaging: software is
set to image capture mode.
-
35 mm photography: camera
back is properly mounted, film is not at end of roll, and motor drive is
turned on.
-
Check fuses.
-
Check flash lamp to see if it
is burned out or not seated properly.
3) 35mm camera back does not
work:
-
Power switch is on.
-
Power saver function is
off. Not every camera has this. Check your manual.
-
Upper / Lower switch is set
on Lower.
-
Camera back is properly
mounted, film is not at end of roll, and motor drive is turned on.
-
Check fuses.
If camera back is
jammed, you may need to have it serviced.
4) Digital imaging: the flash
works, but there is no image on the screen:
-
Upper / Lower switch is set
on Upper.
-
Software is set to image
capture mode.
-
Digital camera is turned on
and is properly mounted/aligned.
-
Flash intensity (21,22) is
not set too low or too high.
5) The flash works but the
Polaroid attachment does not work:
6) Operator cannot see an image
of the patient’s eye through the eyepiece:
-
Lens cap is off.
-
Illumination light is on.
-
Barrier and Exciter filters
are both off.
-
Check diopter compensation
knob (5) for proper position.
-
Check angle lever (6) for
proper positioning.
7) Good focus is not possible:
-
Check the eyepiece for proper
adjustment.
-
Check for correct position of
the diopter compensation knob (5)
-
Check for good pupil
dilation.
-
Determine if the patient has
a cataract or corneal problem that may prevent good focus. Prior use of
gonio gel can prevent good focus.
Image Defects and Artifacts
These descriptions may apply to
the image that is seen by the operator when looking into the eyepiece or to the
resultant image on-screen or on film.
1) The periphery of the image is
dark:
Cause: The camera is too far
away from the eye and/or the eye is not dilated enough.
Solutions: 1) Re-adjust the
alignment (forward or backward) of the camera to achieve even illumination. 2) Change the
illumination diaphragm lever (16) to "S" and/or try a more narrow
view (35 or 20 degrees) if dilation will not improve with more drops.
2) The center of the image is
dark:
Cause: Poor dilation. Improper
alignment contributes to the effect.
Solutions: Re-adjust the
alignment (forward or backward) of the camera to achieve more even illumination. Change
the illumination diaphragm lever (16) to "S" and/or try a more
narrow view (35 or 20 degrees) if dilation will not improve with more drops.
3) Image flare or washed out
image (overexposure):
Causes: The camera may be too
close to the eye. The flash intensity may be too bright. The illumination lamp
may be too bright. The illumination diaphragm may be set on "S" when
photographing through a widely dilated pupil with the 50 degree angle of
coverage.
Solutions: Re-adjust the camera
alignment (back up). Turn down the flash intensity (21,22) if the captured
image is washed out. Turn down the illumination lamp (28) if the eyepiece view
is washed out. Only use the illumination diaphragm "S" setting (16)
on a relatively small pupil.
4) The eyepiece image or the
captured image is too dark (underexposure):
Cause: If the image through the
eyepiece is too dark, then the illumination lamp is too low and/or the pupil
is not well dilated.
Solution: Turn up the
illumination lamp (28). Try to improve dilation. Use the "S" setting
on the illumination diaphragm lever (16).
Cause: If the captured image is
too dark, then the flash intensity is too low and/or the pupil is not well
dilated. A small pupil will cause an unevenly illuminated dark image.
Solution: Turn up the flash
intensity (21,22). Try to improve dilation. Use the "S" setting on
the illumination diaphragm lever (16).
5) There are white spots on the
retinal image when looking through the eyepiece and on the captured image:
Cause: Spots on the objective
lens (4).
Solution: Carefully clean the
objective lens following the instructions in the camera manual. Do not use
facial tissue. These lenses are specially coated and easily scratched. Take
care to use the lens cap when not in use and avoid bumping the lens into the
patient’s nose.
6) Your color slide film comes
back black, without an image on it:
Cause: Either the flash was not
firing or more likely, the film was not advancing.
Solution: When loading the
film, watch the rewind crank to be sure the film is advancing.
7) Your image has what seems to
be a white curtain coming down over it, or the image is totally white.
Cause: You have fired the flash
while the patient is blinking.
Solution: Tell the patient
"don’t blink" just before you fire the flash, or hold the eyelid
up.
8) Your image has a crescent at
the edge of the frame.
Cause: The light from the
camera is striking the iris.
Solution: Move the camera in
the direction opposite the location of the crescent.
9) Your color slide film has some
overlapping images:
Cause: The film was not
advancing properly.
Solution: Take more care in
loading the film. Be sure the film is seated properly.
10) Your color slide film has
some frames that have only partial images and some images that look like they
did not develop properly.
Cause: The camera back was
opened before the film was re-wound.
Solution: Always turn the
re-wind crank clockwise to determine if there is film loaded in the camera
before you open the camera back. If there is film loaded and not re-wound, the
crank will stop turning.
11) Your color slide film has
images that seem to be cut in half.
Cause: The shutter is not
synchronized with the flash. This can only happen with camera backs that have
adjustable shutter speeds.
Solution: Be sure the shutter
speed to set to "X" or 1/60 or slower.
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