Hi, My 6yr Old States That She Sees Red &

Hi, my 6yr old states that she sees red & blue spots / dots all the time. She says that she has always seen them. That they go to sleep when she does and wake up when she does. They don't to affect her in any way and as she has always had them, she just lives with them. alongside that she has been flagged in school as being potentially dyslectic and she does get headaches approx. once or twice a week.
I have taken her to the opticians who state that her eyesight is perfect and that there was nothing wrong that they could see. Do I need to be worried, or is it just a querk she will have to grow up with?