Zeiss VISULAS YAG III, Руководство пользователя

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Operation of the device
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Focus shift and defocusing
The optimal mechanical effect of the optical breakdown occurs at a specific
distance from the focus of the therapy beam. For this reason, the aiming
beam and therapy beam of the VISULAS YAG III are not parfocal, but are
shifted (focus shift). Depending on the application, you can select one of
three settings:
•
Posterior:
Labeled as post., switch to the right.
The therapy beam is focused 150 μm posterior to the aiming beam focus.
This setting should only be used for applications in which the area to be
treated is posterior to the tissue to be protected (see also Fig. 2).
•
Anterior:
Labeled as ant., switch to the left.
The therapy beam is focused 150 μm anterior to the aiming beam focus.
This setting should only be used for applications in which the area to be
treated is anterior to the tissue to be protected.
•
Zero:
Labeled as 0, switch in mid-position.
The therapy beam and aiming beam are focused in the same plane
(parfocal). This setting should only be used for applications in which there
is no tissue which needs to be protected either directly anterior or
posterior to the treatment region.