Page 38
Instruction Manual Easygraph
A graphic representation of
corneal
eccentricity at 30°
for each of the
semi-meridians is shown in the
middle top right. The axis positions
of the central radii are taken into
account in this diagram. The red
axis represents the steeper
meridian and the blue axis the
flatter one. Here too, values
highlighted in red are indicative of
pathological values. The mean eccentricity values for
the two principal sections are shown below the
eccentricity diagram.
The large diagram at the top right titled
Curvature
contains a representation of the sagittal or tangential
radii (see 7.5.4 Page 61 on how to change between
the two).
In the very center is a field titled
“Keratoconus
Level Topogr.”
. Based on a combination of several
indices this output field characterizes the stage of
development of the keratoconus in question. Besides
classification into any of stages 1-4, it may also show
the attribute “possible” in cases of suspected
incipient keratoconus. The present classification has
been adapted as far as possible to Amsler’s and
Muckenhirn’s stages.
Note
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However, one should always bear in mind
that this assessment by the Easygraph software is
entirely based on topography and is not to be
regarded as a basis for a clinical diagnosis. Besides
staging, the software is capable of producing
comments in this field such as “severely deformed
cornea”, “status following corneal surgery” or
“pellucid marginal degeneration”, whenever it
encounters topographic features indicative of such
conditions.
Clicking on the field titled
“Keratoconus Level
Topogr.”
produces a table showing the clinical signs
associated with each of the five keratoconus stages
developed for the Easygraph. It must be stressed
again at this point that a diagnosis of a keratconus
(especially in incipient cases) without taking into
consideration all relevant clinical information is liable
to be wrong, as similar pictures may also result from
irregularities of the lacrimal film or cornea or from
fixation problems.