You really should have active data if you want a worst case eye diagram.
Intersymbol interference, jitter and line reflections will vary depending
on the data. Assuming your data has 2 or more states, transitions at fixed
intervals,is random and has some sort of preamble that is fixed, you can
trigger on one edge in the preamble and then look at the eye later down the
data where it is random and see the worst case with a long persistence
setting. I don't know if this will work for your data. Hold off may help
triggering where you want.

Regards,

Mark