My MBP with 17" glossy screen is about 15 months old. I had so far been using it with screen brightness level set at 7 bars out of 16. But, since the past few days, I've noticed that 7 bars is too dark. I have to set the level at 9 or 10 bars to feel comfortable. Nothing else in the MBP settings or the environment have changed. I don't use any of the auto dimming features. I'm wondering whether it's the MBP or my eyes that are deteriorating. Has anyone experienced or heard of gradual dimming of MBP screens over time? Can anyone suggest causes for dimming? (LED failure?) BTW, I use isopropyl alcohol to clean the screen. I doubt this could be a cause because I had been doing it for the past 15 months. But a warning: The little black cleaning cloth that comes with the MBP leaks blue-black ink. I never used it.