Pupil not dilating properly after cataract surgery

I had cataract surgery on one eye 5 months ago. The pupil in that eye now doesn't dilate properly, so when I go from a bright space to a dim space I'm effectively blind in that eye, and conversely I need sunglasses for the reverse. I'm scheduled to have the other eye done and I'm hesitant if I'll have the same problem in that eye. Anyone dealing with the same problem?