2x now in diff times after intense exercise i saw a flashing ring on right eye that gets bigger and goes away w/o headache. no eye condition. what is?

Visual migraine: This is likely a visual migraine, which occurs without a headache in many cases. If it clears completely in 15-20 minutes, it is very unlikely to be a retinal or neurologic problem. However, you should still have a complete ophthalmic examination with dilated exam of the back of the eye including retina and optic nerve head. I also recommend a visual field test at your ophthalmologist's office.