The Bubble Study, was that during an Echo Cardiogram? My most recent Echo Stress they injected a substance that highlighted blood flow, they said they could use saline as well, just shake it up before use to introduce bubbles. I saw it race through my heart on the monitor.
I lost vision twice in one eye, minutes long each time, attributed to vascular constriction, they referred to it as amaurosis fugax. /en.m.wikipedia.org/wiki/Amaurosis_fugax
Did your vision return? The PFO seems to be a factor in clots, did they place you on blood thinners?