Get his blood pressure checked. My girl had the same thing. Eyes moving rapidly, but did not fall over, lasted just a couple minutes. I already knew she had a BP problem and she was on meds. I called her cardiologist who said bring her in now. Her BP was over 200. To high even for white-coat syndrome (fear of doctors in white coats).
Her BP was never controlled well, but it was monitored closely (she passed away from cancer at age 12)