Bill Dengler is trying to become an Italian citizen. He has all the documents ready to go. But Mr Dengler, an American software engineer who was born fully blind, cannot make an appointment with the Italian consulate in San Francisco. Its booking system uses a colour-based calendar, which is not legible to his screen reader, a device that delivers a website’s content in audio form. And, perhaps because slots fill rapidly, rules prohibit him from hiring someone to make the appointment on his behalf.