It is quite possible for the BP to be causing harm to you and the baby at 140/90 and even below that, it all really just depends on what is truely going on, which the doctor can't tell you with any certainty.
Don't ignore or be comfertable with a reading of 140/90, while in a non pregnant person doctors may think this reading is okay and boarderline high BP, a pregnant woman is much different.
The BP that docs want you to have is 120/60, 140/90 is the guise for hypertension.
Regarding the blurry vision. Any swelling to the cranial area around the eyes will cause your eyes shape to change. Your vision is based on where the light hits the retnia along the back of the eye. If your farsighted it hits to short, if your near sighted it hits to long. When you have swelling and the shape of your eye changes even slightly, this causes the light to now hit in a different spot then previously, thus it actually changes how well you can/cannot see. People that wear contacts or glasses more readily notice this because suddenly their corrected 20/20 vision isn't that anymore.
I can always tell when I am going to have allergy problems a few days in advanced because my vision gets blurry from the swelling in my sinuses. I had the same problems when I had PE. I did find that wearing my glasses alleviated it some (because there is a difference in the way your prescription works in glasses and in contact lenses) in my second pregnancy. In my first pregnancy nothing made it better.
Mommy to Alex and Mason