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PowerCalc v1.0
is an ophthalmic eyeglass lens design analysis and graphic display
tool. It is primarily intended for application on line free bifocal progressive lens surfaces but
can be used with toric, aspheric, and spheric surfaces as well. The lens
surfaces must be formatted as 3D X-Y-Z point files. The file format should be a
square data grid of at least 80x80mm and comma delimited in 1.0 mm point
increments but other increments such as 0.5mm is also acceptable.
The basic features of PowerCalc are separated into two categories:
Analysis and Graphic display.
Analysis Features:
1.
Displays the basic file data information of name, number of data
points, and point increment.
2. Offers a selection of common Refractive Indices
(R.I.) to use or a custom refractive index may be entered.
3. Allows from 1 to 3 Test point locations of either 4
or 6 mm regions anywhere within the displayed surface area.
4. Test point results of surface power and cylinder are
identified by axis may be displayed in either diopters or radius of curvature.
5. Selected Differences between the Test points are
displayed to determine the net power or curvature change.
6. Displays the minimum and maximum surface power and
cylinder/astigmatism values of the entire surface region.
7. Displays a "Gradient factor", a custom mathematical
function to determine the negative "swim" effect of the lens surface design with
a simulated frame size and location. This value is useful to help determine the
comfort fit of the design with each Rx user. This factor typically applies only
to bifocal progressive lens designs. This value is automatically updated when the frame
size or location is altered within the Rx menu.
8. Test point locations are retained (unless cleared)
when design files are changed for ease of analyzing multiple files which have
the same design parameters.
Graphic features:
1.
Displays a colored contour graph and matching colored data legend
immediately upon acceptance of a data point file.
2. The displayed Graph is selectable between surface
power and surface cylinder with independent drop down diopter resolution
selections.
3. Selected Test point regions are accurately scaled and
displayed on the graph as an overlay.
4. Offers a Zoom function capable of a variable 10~30mm
rectangular region for closer inspection of the surface contour.
5. A default eyeglass lens frame overlay may be applied
to the graph to enable design perspective.
6. An Rx prescription menu is offered by which a
patient's individual parameters such as pupil distance (PD), pupil height and
actual frame size may be entered in conjunction with the design's fitting point
to create a precise frame overlay on the design. The back curve Rx is also
calculated and displayed to assist the optician with the Rx process.
7. All legend and Test point values are automatically
updated when modifications are entered or menu items selected.
8. The options menu offers a selectable "nominal" value
location entry when the default location (center of the data) is not optimal for the graphic display of particular type surfaces.
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