Screen size calibration
Screen calibration allows the system to calibrate the patient’s screen to determine the correct optotype sizing. It is important these steps are followed correctly for an accurate result.
Credit card calibration (default):
The ECP should direct the patient to follow these steps:
Find a bank card (this is outlined in the invitation email)
Align the bank card with the graphic on the screen (figure 1)
Move the slider on the right to expand/shrink the card outline on the screen until it matches the patient’s bank card
When the graphic is the same size, the patient selects ‘Card matched’
On the ECP screen the ‘Next’ button will then become active (figure 2)

Figure 2
Manual measuring calibration:
If a patient does not have a bank card present, select the ‘No card available’ button to measure the screen manually
The patient will need a measuring device with mm measurements (e.g. ruler)
Instruct the patient to measure the height of the letter H on their screen (figure 3)
Write this value in the field available on the ECP screen (figure 4)
Select next to continue to the next stage.

Figure 4