I was diagnosed with MMD (bilateral) and had direct (EC-IC) bypass surgery on the left-side in August of this year. I am worried about the other side.

I have never had any "symptoms" on the other side. The surgeons here generally suggest monitoring the other side for symptoms and then decide whether to undergo surgery.

I know that MMD is a progressive disease. I read that people with MMS often develop MM vessels after they receive surgery on one side.

I'm currently residing in Korea and don't know what the process is like in other countries. Can someone inform me? Also, does anyone know of bilateral MMD patients who only need surgery on one side? Or will the other side progress further (resulting in TIAs and strokes) as I get older?   

Thanks in advance.

this is good advice from Heath.  Better to find out now if you can, than w/ a stroke later.
Best wishes...keep us posted on your progress!

Yeah, don't ignore the signs.  make sure your family, close friends, co-workers, etc also know the signs.  My son was too young to know & tell us anything (we didn't know either), but I remember him complaining about the sun hurting his eyes. other than the couple of migraines a few months before, we had no other cues that he was about to have a stroke.