The authors measured the percentage light transmission of filters on different Bagolini filter bars to evaluate whether a difference exists in density of suppression or strength of abnormal binocular single vision (BSV). A Sekonic dual spot photometer was used to measure light transmission. The following were compared: two Sbisa bars (Sbisa and Bagolini filter bars), different bars of the same make, and repeated measures with the same bar. Data was provided by 33 of 36 participants. Light transmission was found to be similar for bars at higher filter numbers above nine. The percentage of light transmission did not reduce down any filters in a consistent way with greater variability for lower number filters. The authors conclude that measurements of density of suppression or strength of abnormal BSV should not be compared if undertaken with different bars, unless from two different new Bagolini filter bars. When considering repeatability of measures, measurement should be done at least two minutes apart as measurements appear to cause a short-lasting reduction in suppression or strength of abnormal BSV. These are useful findings with clinical application.