You are writing of Xenon headlights and this is another example of stupid EC Law. The relevant Directive requires that, because of their brightness, Xenon lights must automatically adjust their beam height depending on the angle of the car to the road. Unfortunately, on an undulating road, these automatic beam height adjusters are usually too slow, resulting in the lights either pointing at the ground in front of the car, at the sky, or, in your case, directly into your eyes. As well as that, the systems are fragile and frequently fail, but the cost of replacing them is always at least £600 a side and sometimes as much as £1,200 a side. So owners don't replace them. EC law also takes no account of dipped Xenon lights shining directly into the door mirrors of cars about to be overtaken. See www.blindedbixenon.co.uk