Keratron
™
Onda Installation and operating manual
OPTIKON 2000
Cod. 161401EN
5-2
2015-03-27
Rev.C
Employs a
user-friendly
interface to notify the operator of the status of
the unit and any errors
3.
Joystick with b
utton: allows the cart to be moved in the X-Y-Z directions for
proper positioning of the optical head in relation to the patient and the start or
confirmation of the image acquisitions.
4. X-Y-Z cart
5. Optical head, with mires cone
6. Adjustable chin-rest with forehead-rest for positioning the patient during the
measurement.
5.1.1
TOPO-ABERROMETRY WITH THE KERATRON
™ ONDA
The requirements for conducting the topography and the aberrometry are not the
same. A good reflection topography requires uniform mires and especially, for those
at the center of the cone or Placido disk, a very small and distant hole.
Instead, aberrometry requires a larger field of view of the maximum pupil and optics
placed relatively close to the eye. For this reason topo-aberrometers generally
sacrifice the coverage of the central zone.
To solve this problem, the Keratron
™ Onda adopts a patented system of “
retro-
mire
” located behind the filter mirror that separates the two optical paths (refer to
Figure 5-2: operating principle of the back-mire
The mires cone possesses 26 alternating black/white and white/black edges to which
two from the back-mire are added (211 and 212 in Figure 5-2). In this manner the
