How does the 'Comparison' mode work?

Selecting/Positioning Bulbar Redness

  1. When your chosen image has been imported into the viewing area select 'Bulbar' mode from the menu,

  2. Then click 'Comparison' and select the 'Analyse Bulbar Redness Grading Scale 0-4' button. 

  3. Then left-click on the image to position the first circle, when complete left-click again to place the second circle, as shown in Figure 1.

  4. Using your mouse click in the middle of the circle and position each one in your area of interest.

Note: The comparison tool should be used for comparing areas on the same image. Images should not be photoshopped or stitched together outside of the capabilities of the software (e.g. cropping and rotating in the media gallery). To conduct a comparison on two different images, users should analyse them separately and then view them together in the generated report.

Adjusting the Circles

  1. To resize the circles, place your cursor on top or on the bottom edge of the circle. You will see the cursor change to ‘row-resize’ this allows you to adjust the height.

  2. Moving the cursor to the left or the right edge of the circle, the cursor will change to the ‘col-resize’. Click and move left or right to adjust the width of the circle.

  3. To enlarge or shrink the circle, place the cursor on the diagonal edges of the circle. You will see the ‘move’ cursor appear, click, and move in or out in the diagonal direction to enlarge or shrink the circle. Please note the resizing on one circle will be simultaneously duplicated on the other. See Figure 2 below to see the resizing of circles. 

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Figure 1

Calculating a measurement

Once the circles have been correctly positioned the results will load automatically.  On the result panel, the results are shown for 'AREA 1' and 'AREA 2'. The vessels in the circle area will be shown in black to give a visual representation of the vessel coverage, Figure 3.

Figure 2

  • The conjunctival total redness is measured with a grading scale of 0-4 and with an accuracy of one decimal place.

  • While the results are being displayed, the circles can be adjusted if necessary and the results will refresh automatically, Figure 3.

Redness Map 

  1. After the comparison areas have been drawn activate the following feature by clicking 'Redness Map'

Figure 3

2. Once activated, the area will appear as a colour heatmap, Figure 3. 

The grading chart is based on the Efron Grading Scale 0-4 appears in the results panel at the bottom left of the screen.