Headlights problems of the 1999 BMW 528

I have a 1999 BMW 528it wagon. Until a month ago my husband had a 1994 BMW 318ic. All four headlight lenses in these cars became quite filmy, and have been for some time, which I believe to be a significant safety hazard, as it diminished the ability to see at night. These cars were not antiques, and the safety equipment should hold up for a minimum of 10-15 years, in my opinion. Will you please make BMW do something to remedy this situation at the company's expense, not the owner's? I have a 1989 Volvo, and its lenses are still fine, so this is not something that happens in all cars.