I started getting lights flashing in my eyes back when I was around 9 or 10, I had been on ADHD pills starting around the time I was 7 that really messed me up and would prevent me from eating lunch by suppressing the appetite and would also keep bowel movements from occurring on those days where the medicine was used.
Within the exact same week as the flashing in my eyes began I became very sensitive to light and my personality became much more shy and fearful.
I went to the optometrist and mentioned the flashing lights way back then, the guy checked for detachment I think it was and didn't find anything out of the ordinary through the whole exam.
I believe I've had some mild form of Chronic-Fatigue-Syndrome since that day way back when which got worse and worse as I got older and the stresses in my life increased