Calibration for subject's viewing distance

For Symbol Acuity and Crowding the viewing distance must be calibrated based on the size of the image on your screen, however for all tests, it would be best if the viewing distance was correct. Use the resources below to calculate the correct viewing distance

Text instructing to measure a line on the screen and use the calibration page to find the correct viewing distance

Viewing distance for Symbol Acuity and all tests EXCEPT Crowding

X axis, length of line measured on your screen (cm). Y axis, correct ciewing distance (cm). Note it is not recommended going past either bounds of the graph

Viewing distance for crowding

X axis, length of line measured on your screen (cm). Y axis, correct ciewing distance (cm). Note it is not recommended going past either bounds of the graph