It doesn't sound it to me if you aren't getting the headache part of it, and it's affecting both eyes, but I'm not an expert - just a migraine sufferer.
I'm going to move this over to our Eye Care community, where our ophthalmologist can help you with this.
I hope you get some relief soon. :)
FOR READERS OF THIS POST; inappropriate sinus tachycardia (IST) and postural tachycardia syndrome (POTS) are syndromes with overlapping clinical features of excessive sinus tachycardia.
FOR RACHL180 This sounds much more like a cardio-vascular or neurological problem than exercise induced migraine variant Reminds me of the story of the person that consulted two different doctors and got 3 different opinions. I would be sure you have discussed this with the cardiologist and make sure you can safely 'intensely' exercise. If there is any danger of serious arrhythmia you may need to switch to less strenuous exercise.