Keratron
™
Onda Installation and operating manual
OPTIKON 2000
Cod. 161401EN
7-33
2015-03-27
Rev.C
By pressing [Parameters], it is possible to display the panel shown Figure 7-55 in
which it is possible to set the following parameters:
1.
From =
Starting accommodation. If = 0D, the first measurement will be
calculated using the "infinite" focused target or, more precisely, the pre-
measured or preset remote point. It is however possible to 0.5 or
+1 or +2 diopters “beyond the infinite" as starting value in order to verify that
this remote point corresponds to the actual one.
2.
Step =
The step in diopters between consecutive measurements. If the
values of “From” and Step” are changed, pane “Fogging (D)” in the lower
section shows the updated sequence of the measurements that will be
performed. NOTE: the allowed “Steps” depend on the value selected for
“From” (if different from 0D), because the measurements must include the
one performed at the remote point (0D), which is highlighted in green.
3.
Nr. Of measures =
Number of consecutive measurements. It is possible to
select from 4 to 8.
4.
Stimulus interval =
Duration in milliseconds of the stimulus used for each
measurement. The value must be chosen so that the patient has the time to
accommodate without too much effort.
5.
Graphic X axis =
“Fogging”
or
“Stimulus”
.
“
Fogging
” represents the target defocus
referred
to the remote
point, which is displayed in the “Fogging (D)” pane in the lower
section.
“
Stimulus
” represents the
absolute
defocus of the target, which is
equivalent to the sum of the initi
al “defocus” + “Fogging” .
NOTE : Axis Y of the chart always shows the same “Stimulus”.
Pressing OK the set parameters are permanently stored in the Keratron
™ Onda.
To start the sequence, it is sufficient to press the joystick button.
At this point, it is possible to decide whether to activate
“Auto-Rx”
(yellow button)
in order to automatically detect the
“defocus”
.
Alternatively, if the patient's refraction is know (because it can be acquired from a
previous “Auto-Rx” measurement), it is possible to use the cursor to set the
“
defocus
”, that is the refraction's
sphere-equivalent
to VD=0
, and disable the
“Auto-Rx” (grey button).
To start the measuring sequence, it is necessary to frame the eye and press the
joystick button at the distan
ce of OK. If “Auto-RX” is enabled, the test starts
automatically at the end of the “Auto-RX” phase; otherwise it starts immediately.
During the test, it is important to keep the eye centred so that the retinal reflection
image is visible and in order to prevent as much as possible spurious reflections
from the cornea and iris (in the upper left box).
