I do not have such a bright spot. Floaters yes.
I actually have similar symptoms, see the post that I submitted a couple days ago. Mine is like a smudge near center of vision with a curved white line. I get it when moving eyes left or right in only one eye, and only in lit areas. For size reference, if I held up a dime a foot away, its about that size near or just off center of vision. Move eyes and I can see it, goes away right away. Ophthalmologist says I have a PVD underway and to watch for the signs of RD (bright flashes/lightning bolts, increased floaters, shadows/loss of vision). Since I had a detachment in my other eye last year they want to see me back in 3 weeks unless symptoms appear sooner. I went through vitrectomy with my other eye for the RD repair, hoping that if it happens to my other eye to catch it quicker. Dr. said don't hesitate to call day/night if I have the symptoms and you can bet I will this time. Best of luck.