What Causes Headache And Blurred Vision While On VP Shunt?

I am a 34 year old woman with hydrocephalus. I have had a vp shunt since birth and had it replaced when I was 6. I was havung bad headaches so I went to ER as they say I have no neurosurgeon. Now as mine retired. Ct scan done and shunt study. Said it was ok. Blurred vision and headache continue. Went to opthamologist. Put prisims in glasses and after a month I felt good for about a week. Headaches anded blurred vision back. I have an appointment with a neuro opthamologist a month from now. Would you think the cts and shunt studies should be redone?