The logMAR chart is displayed by selecting the LogMAR icon on the toolbar, pressing F1 on the keyboard of selecting LogMAR on the remote control handset.




The LogMAR chart has a number of advantages over the Snellen chart. For this reason it is recommended as the method of choice for measuring visual acuity.


Each row contains five letters (except for the larger sizes) and the letter size changes in steps of 0.1 logMAR between one row and the next.


The Thomson Test Chart allows up to five letter / optotype sets to be defined for each optotype for the LogMAR chart.  The Optotype Sets are selected by selecting the O icon on the Secondary Toolbar or by pressing O on the keyboard or remote.


The five defined letter/optotype sets can be customised by selecting Customise letter sets on the LogMAR tab of the Settings screen. Defining letter/optotype sets.


The Thomson Test Chart provides a wide range of options for customizing the LogMAR chart. These options may be selected using the Secondary toolbar or by using the keyboard or remote control.



The various options available in LogMAR mode are described under Test Charts - common features and include: