Since the blind spots are episodic and not present continuously all the time, they could be either due to transient obscuration of vision (TOV) which can occur due to reduced blood flow to the eye blood vessels, or due to migraine
( acephalic type without any headache) or it could be a floater
due to PVD(posterior vitreous detachment
). To give a conclusive diagnosis it is very important to get the eyes examined by an ophthalmologist first and then a physician if need be.