Not a floater. Sounds most like a "scintillating scotoma" which can be caused by serious disease of the eye, brain, heart or blood vessesl but in younger, healthier people is often a form of migraine without headache called "eye migraine" or "ophthalmic migraine"
Use the search feature and archives to read about. See an ophthalmologist.
I visited the eye specialist and she said, it is a migraine, not even an ophthalmic migraine but just the usual migraine. I was so relieved but not taking any chances, what should i do to altogether cure the migraine.
Migraines are usually controlled not cured. suggest you see a neurologist to begin treatment.
By the way. If you only have eye symptoms, do not have headache, nausea or vomiting then you have ophthalmic migraine NOT classic migraine (nausea, vomiting, eye symptoms, sensitivity to light, severe pounding one sided headache)