Use the screen-dimming buttons near the escape button. F1 on my MBP- takes the glare right down. Problem is the strength of the apple displays. ;-) Also, use F.lux (google it, free for both PC and Mac Os) which changes the color temperature of your screen to match white/blue light for daylight hours, and yellow/dim red for night hours, with sunset-inclusive!
Your pineal gland and circadian rhythm will love you!