Keratron™
Installation and operating manual
OPTIKON 2000
Cod. 161501EN
5-2
2014-04-23
Rev.0
3.
Joystick with button: 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 TOPOGRAPHY IN THE KERATRON
The Keratron
™
is a corneal topographer (also called CAVK: Computer Assisted
VideoKeratographer) designed to measure the shape of the cornea and to represent
it as a chromatic map of the axial powers, of the local or Gaussian curvatures or of
the elevations in various formats.
From a "ray tracing" calculation on this shape the corneal aberrometry is calculated
and represented, i.e. the main component of the wave front and its aberrations, due
to the cornea-air interface.
5.1.2 THE
RETRO-MIRA,
THE
BIVALENTE
MIRE
CONE
AND
THE
TOPOGRAPHY
The Keratron
™
mire cone has 26 alternate N/B and B/N edges, to which 2 from the
retro-mire are added (211 and 212 in Figure 5-2:) infra-red. In this way the mires
reflected on the Keratron cornea (Figure 5-2: bottom left) are the same as the other
Keratrons (28, at a uniform rate for the arc-step
algorithm) without any compression
in the centre. This system, apart from allowing better tracing of the photopic pupil is
prepared for a possible "ugrading" of the Keratron topographer
