A B737 Captain reported that while taxiing into position PDX Runway 10L; Runway and Approach Light Systems lights were so bright that the remainder of the airport environment was obscured. Reportedly ATC was unable to reduce the brightness of the ALS.

Narrative

We were cleared to line up and wait on Runway 10L. As I attempted to taxi into position; I found it very difficult to do so even with centerline lights; due to overly bright Runway/approach lighting system in the displaced threshold area in which we were to line up and wait. While holding our position on Runway 10L I informed tower that the lights were too bright and that they were creating a safety hazard by washing out our night vision. I did not mention this to the tower; but the lights also blocked most of our view of almost everything past the lights in the displaced threshold; so it wasn't possible to adequately scan any of the Runway beyond the displaced threshold prior to commencing the takeoff roll. In my opinion; had we experienced a loss of thrust during the initial takeoff roll while at a high thrust setting and low airspeed; I'm not so certain that I would have been able to successfully keep the jet on the Runway due to the bright lights. A flight departing ahead of us also complained to tower about the overly bright lights as they were holding in position from the full length of Runway 10L. According to the tower they are unable to place aircraft in position to hold from an intersection at night; so for that reason they were placing aircraft into position at the full length of Runway 10L. I do not understand why the tower can't dim the lights while an aircraft is holding on the Runway in the displaced threshold; and then turn them up again after the plane is past the approach lights in the displaced threshold; but according to the Tower they can't dim the lights while an airplane is holding in position.