The Snellen chart is displayed by selecting the Snellen icon on the Primary toolbar, pressing F2 on the keyboard of selecting Snellen on the remote control handset. The Snellen chart fully complies with the specifications of BS4724.



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 Snellen tab of the Settings screen. Defining letter/optotype sets.


You may also hide the 6/120, 6/7.5 and 6/3 rows by ticking the Hide 6/120, Hide 6/7.5 and Hide 6/3.  Showing /hiding rows.


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



These options are described under Test Charts - common features and include: