18 year old daughter totaled her '06 Prius (R.I.P)...purchased an '08, package Five (V). This car has H.I.D. lights, however, she was complaining about how "dim" the headlights were, so I had her take me for a drive. To my dismay, I couldn't agree with her more. We're lucky to see about 30 feet in front of us. H-E-L-P!!
Very common issue. Lots of threads about it. I don't have HIDs but many people on this site do and will weigh in on how to fix them real soon. I think its the the high voltage supply.
Do a search. Up top on the left says "search forums" Click on that. I put in key word HID DIM and got a couple hundred hits.