iPad is good for a lot of things but it could really screw up your sleep. The head of the UCLA Sleep Disorders Center says that the luminescence inhibits the production of melatonin in the brain.  Melatonin is a key chemical in sending you drifting off to beddy-bye.

Bill Ray, reporting on the effects of e-reading on vision (Don’t try to sleep with your iPad, doctor warns), says that e-ink screens like Kindle, Sony and Nook do not have that melatonin-inhibiting glare, but users may develop another problem. “Apparently the limited contrast of e-ink screens can cause eye-strain, but at least those with strained eyes are well rested.”

Ray also reminds us that if you do doze off while reading, it’s cheaper to drop a printed book on the floor than a device you paid hundreds of dollars for.

Richard Curtis