This is Video 4 on the basic operation with your Medmont E300
Corneal Topographer.
You'll note that your database is along the left hand side, all patient
information
will be
stored here.
Under patient name Case, initial A,
we can click on that patient name
and bring up the main
patient window,
we also know that there's a plus sign next the patient name
which indicates that
there must be information inside that file.
You can open up the patient file by clicking
once on the plus sign or,
double clicking on the patient name.
In opening up the file we can see that there is one right Topography inside that
file.
If you click on that Topography it will be dropped on the main active window here.
Once we do that
you can analyze these topographies a number of different ways. In the first
way we might do so is to look at the Sim K readings
This is our
Keratometry readings as determined by your Medmont Topographer.
In this case the Flat K is 42.2, Steep K
43.6.
The Flat K is along axis 1, Steep K at axis 91.
We can also see that this cornea has 1.4
Diopters of Corneal Astigmatism.
Next we can click our cursor in the center of the Topography
and determine
the radius of curvature at that point in this case
42.9.
We could click our cursor
at any point on the map
and determine the curvature at that point, in this case
43.5 just inferior of the Apex,
and where the cursor has been clicked
were 1.30 millimeters away
from the center of
the Topography.
The center of the Topography would be the Visual Axis, this would be the point the
patient is fixating
at the moment the map is taken.
We could look at the 3 millimeter 5 millimeter and 7 millimeter
white rings
and the pupil which is
in black, here.
We can use either the pupil or the rings
to determine
the position, shape, or size of any anomalies
in relationship with
the visual axis,
with the pupil,
or to a certain diameter away from
the Apex.
Next
we could look at the
Eccentricity Value here.
Eccentricity is a measure of the rate of Corneal Flattening of the eye.
From the Apex
to the periphery
how high is that rate of change,
the higher the Eccentricity
the flatter the Cornea
becomes as you move toward the periphery.
In this case
from the center
taking this white axis line observe the graph down below.
Along the Horizontal Meridian
we go from, steepest curvature in the center,
to flattest
curvature toward the periphery.
.86 is the measured Eccentricity.
Now change your
axis line to the Vertical Meridian,
and notice there's very little rate of change from center
to periphery
along the Steep Meridian as compared to the Flat Meridian.
That gives us a much lower Eccentricity Value.
We will focus on
Eccentricity
later in the video series to better understand what this tells us
about the eye shape and how it can
help us in terms of contact lenses.
Next we can look at the scale range along the left hand side.
Notice the Topographer is showing us the flattest it can read is 35.23
Diopters here,
steepest it can read is 43.61
Diopters here.
The scale is set for a Normalized Scale range. Meaning
the Topographer will show
from the steepest
to the flattest that can be read on the selected maps along this left hand side.
If you select a Topography that has much steeper curvature
or much greater range of curvature
the scale will adjust for each individual patient eye.
Normalized Scale is the best way to interpret maps to get the best
definition
on each individual eye.
You can also click on this down arrow and select from anyone of the
Absolute Scales.
For instance
you could select
the Standard Power Scale
which changes the scale range
to 35 Diopters up to 50 Diopters.
Now we have a 15 Diopter scale range
that's absolute, absolute, meaning
it will always be
from 50
to 35.
And you can determine where that patients falls within that scale
the redder the colors of the map
the steeper the Corneal Topography.
The bluer or colder the colors are
the flatter the Topography.
In this case
we have
green contours near the center
this is a pretty median cornea,
but notice in Absolute
you lose a lot of definition
that the Normalized Scale would provide. So let's go back to Normalize Scale and
use that as our
default for all maps that we analyze.
This concludes
the Basic Section on your Medmont E300 Corneal Topographer.