Sun visors

I sat in a Cadillac dts at a car show a couple years ago, the SF international car show, and it had a really nice interior and nice soft leather and everything but I noticed one thing that I felt was a pretty good feature in this car.  It had sun visors that had extensions that you could slide out toward the center interior mirror to block out more of the sun from the driver and passenger's view.

I think this would be a good addition to vehicles sold because there's always this little bit of the sun visor that doesn't guard your eyes from the sun.  But I am unsure if maybe General Motors has a patent on that design and maybe that is why other cars don't come with it.

Also I always liked the idea of having sun visors in the rear of 4 door vehicles but this is probably not a very good idea.  Maybe it should be tested out to see.  When younger and just a passenger, there is nothing to prevent the sun from hitting your eyes while seated in the rear of a vehicle and it is kinda annoying especially since direct sunlight to the retinas is not very healthy.