Calculation of silent substitution stimuli for full-field electroretinography using the SilentSubstiTutor application

The silent substitution technique allows photoreceptor directed stimulation (i.e., the selective stimulation of different photoreceptor types or a specific combination of photoreceptor types).

Calculation of these stimuli is not trivial, requiring complex matrix calculations based on specific datasets (spectral power distributions of primary lights, photoreceptor fundamentals, and optical densities of pre-receptoral filters). Several tools have been published that facilitate these calculations, including an excel file and a python library, but these are difficult to use without prior knowledge.

We introduce an online application that allows calculation of silent substitution stimuli in a graphical user interface (GUI) for common use-cases (3 to 5 primary lights, periodic stimuli modulated around an average setting of the test field, 10° standard observers).

The goal is to provide a practical tool that can be used in these cases, but that can also be used as a teaching tool for beginners who plan to use the more sophisticated methods.