.focuseye is a read/write sysvar (mem location 511). It indicates which of the bots 9 eyes should be used to populate the refvars. A value of 0 indicates .eye5 should be used. A value of -1 indicates .eye4, and value of +1 indicates .eye6 and so on for values from -4 to +4 inclusive. If a value outside this range is stored to the location, it is MODed in such a way that the value refers to one of the 9 eyes. A value of -5 corresponds to .eye9 for example, a value of 5 to .eye1 and so on.The refvars are updated using the specified eye during the same cycle .focuseye is modified. Values stored into .focuseye persist across cycles, can be read by bot DNA and the specified eye will be used for refvars until a new value is stored into .focuseye.