OCULUS Easygraph 70620 Instruction Manual page 61

• Curvature radius
Here you can determine whether to have the
sagittal or the tangential curvature displayed.
The tangential curvature is the curvature of the
cornea at the measuring point.
The sagittal curvature is equivalent to the
distance between the measuring point and the
point where the perpendicular to the tangent at
the measuring point intersects with the axis.
In the tangential presentation mode irregularities
in corneal geometry appear more pronounced.
Tangential Curvature
r
T0
In the sagittal presentation mode the curvature
value depends on the slope at the measuring
point; furthermore, the position of the optical axis
comes into play. The sagittal presentation mode
Sagittale Curvature
.
r
S0
is more representative of the influence of the
cornea on the patient's visual acuity.
Instruction Manual Easygraph
r
T1
.
r
S1
The "Curvature radius" button refers to all
modes of curvature presentation, e.g.
-color topographic image,
-3D image,
-diagrams of the Overview Display,
-Fourier analysis,
-etc.,...
It does not refer to
-keratometric data,
-color presentations of refraction,
-height data,
-contact lens fitting.
• Presentation
Here you can choose whether the diagram is
shown as a complete picture (the not measured
parts are interpolated and marked with black
dots) or as an original picture (not measured
parts are white).
• Color table
In addition to the "Internal" color table used by
OCULUS you can also use an "External" color
table. This enables you to adapt colors to other
topographs for
examinations. The external color table is stored in
the file C:\EASYGRPH\EASYGRPH.COL. Here
64 shades of color can be defined with their RGB
values.
• Central Radii:
Use this button to select whether central radii
(rh/rv) are to appear in mm or diopters in the
Overview Display.
• Date Format:
Is used to set the date display. The following
formats can be selected:
Day/Month/Year
Month/Day/Year
or Year/Month/Day
as well as the sign separating month, day, and
year.
Page 61
better comparison
(DMY),
(MDY),
(YMD),
of