When comparing two items side by side, is it better to show the given or known item first or show the unknown variable first?
I have a tabbed interface to show the differences of common eye issues compared to a normal eye. The tabbed interface is a fixed UI parameter and in this context is intended for a user to browse various eye ailments to compare a graphic side by side with a normal eye.
The common eye content will be the same across each tab. In this setup, I'm assuming a user will perform a rollover action over multiple eye-disorders in a session.
Is it best to place the common eye graphic on the left or on the right?