What Causes Blurred Vision And Dizziness While Having High BP?

Last night I have blurred vision and seeing line in eyes , dizziness. Also had blood pressure of 186/105 when we took it at 9pm. I take coreg 25 mg at night and maxzide 75/50 in the morning. Blood pressure has been regulated at 125/80 for several years. These symtems happened very suddenly. I rested in a chair and within 45 minutes, the blurred vision was gone and blood pressure did come down to 146/85. There were no other symtems and I slept well. Any ideas of what caused this?