I've struggled for years to get good sleep; and like most people do, I spend a lot of time with screens during the day and at home with my cell phone, TV, computer, etc. It always took a long time for me to fall asleep, much less even *feel* sleepy before going to bed. I'd researched light blocking glasses before stumbling across Blublox, but most of these offered products did not include a prescription, and these Blublox glasses do. I also get migraines, so having my prescription in a pair of glasses so that my eyes don't strain any more than they should is important. These glasses are lightweight for a fairly heavy prescription, comfortable, and work just as described. About ten minutes after putting them on, even if I'm watching TV or looking at my phone, I start to feel sleepy, and things slow down. Still, it's good to note that for them to be most effective, screen time should be stopped at a certain amount of time before heading to sleep as well. The glasses are a good way to tell my brain that sleeping time is coming. I fall asleep much better now and my eyes don't feel so tired. A wonderful product.