Welcome to Just Answer and thanks for your question. How long has this been going on? What tests has your provider done so far?
Thanks for the additional information. The results of the blood tests will guide where to go from here. Some possibilites are anemia or thyroid dysfunction. The flashing lights can be from the vitreous (gell-like fluid within the eye) pulling on the retina which can give interim blinking lights. You can read more about it below. It is probably just that since it hasn't gotten any worse since you've had it and you don't mention floaters or darkening of the vision as well. Your ophthalmologist will be able to look at the back of your eye and determine if it is anything to be concerned about. Blinking lights can also be from a migraine (with or without pain).