An acute condition which renders the sufferer incapable of remembering why he or she unlocked their iPhone, even when this was done as little as one or two seconds previously.
It arises due to the multitude of gleaming white numbers in little red circles presented to the sufferer once the phone is unlocked, indicating suddenly riveting unread emails, thrilling Facebook and Twitter messages, essential weather forecast for tomorrow, exciting app updates, tantalising missed Skype calls, potentially life-changing calendar invites and many, many more, which inevitably cause the sufferer to forget immediately what they were actually supposed to be doing, e.g. making a simple phone call.
She: Why didn't you pay the credit card bill?
He: I was going to but when I looked at my phone, I saw five new emails, which I had to read, and a missed Skype call, which I had to return … and then I forgot what I was supposed to do. Sorry, I think I've got iPhone Blindness.