Last night I was reading in bed when I suddenly lost total vision in my right eye, as if a vertical curtain had been drawn across it.
After 3 minutes my vision had returned to norma.
I would see GP to be sure. No other symptoms, weakness etc? I'm not sure if migraine can affect only one eye, or if it's always both, but get it checked to be safe.
I agree with pixie.......commonest cause is migraine....however as your BP is abnormally high, it could be a condition known a Amaurosis fugax (Google it)