The Binocular Balancing test is selected by clicking on the corresponding icon on the Secondary Toolbar or by pressing 4 on the keyboard or remote.




This displays letters and other optotypes in three “windows” at the bottom of the polarised mask.


These windows are aligned with the polarizing filters so that the stimuli presented in the top window are seen by the right eye only; the stimuli in the middle window are seen binocularly and the stimuli in the bottom window are seen by the left eye only.


This allows the practitioner to simultaneously assess the vision in both eyes monocularly and binocularly. This is particularly useful in the final stages of refraction for binocular balancing.


Clicking on the O icon in the Secondary Toolbar or pressing O on the keyboard or remote causes the letter displayed to rotate around the 5 sets of default letters.  The letter shown is the first letter on the LogMAR row of the same size.


Clicking on the R icon in the Secondary Toolbar or pressing R on the keyboard or remote causes the letter displayed to be randomised.


Different optotypes can be displayed by selecting the required optotype from the pull-down list on the Secondary Toolbar or by pressing the SHIFT + Horizontal cursor control keys on the keyboard or remote.


The size of the letters displayed may be changed using the Vertical Scrollbar on the Control Window or by pressing PgUp or PgDn on the keyboard or remote.





The various test options are selected as follows:

Mouse

Select the corresponding button in the Secondary toolbar for default (O) or randomised (R) letters

Select the optotype from the pull-down list


U Adds a vertical duochrome split through the centre of the windows


Use the Vertical scroll bar to change the size of the letters / optotypes





Keyboard

O Sets chart to default arrangement of optotypes.

R Randomise optotypes


U Adds a vertical duochrome split through the centre of the windows

Use SHIFT+ Horizontal cursor control keys to change size of optotypes


Remote

O Sets chart to default arrangement of optotypes.

R Randomise optotypes


Use SHIFT+ Horizontal cursor control keys to change size of optotypes


U toggles the vertical duochrome split on and off