The white spots can be caused by a few things including blood pressure. They are called floaters the eye has a jelly like substance in the middle and when the pressure differs it leaves gaps in the pressure of the eye hence the floaters drifting in and out of your vision.
Blood pressure can also be responsible for "flashing lights" this is alot more serious and can lead to a retinal detachment which in some circumstances the vision cannot be restored.
If you have any symptoms please ask your doctor as a "silly question" may be all they need to check your BP and pinpoint a problem.
Bec