‘Aha! Here is something. How about a trade magazine for opticians?’ said O’Singh. He plucked a biro from his haversack and a mangled notepad, which he laid on top of his newspaper and scrawled away, head bowed, until he had finished: ‘The opticians’ trade magazine could format the lay-out of its articles similar to the way the letters are arranged on the eye test charts, starting with the biggest, most easily discernible letters on the first line; subsequent letters decreasing in size and legibility as they progress further down the page.’

O’Singh capped his pen and turned to the passenger on his left. ‘I knew of a man who visited an optician’s once,’ he said, as freely and easily as if he had known this travel companion all his life, ‘who had such poor eyesight that he started reading the eye chart before he had even stepped into the surgery.’

O’Singh stared intently at his fellow passenger, who was slowly recoiling into his seat.

‘“But how?” you might ask,’ continued O’Singh, anticipating the passenger’s incredulity.

‘“I” this man had said confidently, reading what he thought was the first letter on the chart. How could he have had such bad vision if he was able to read the sign from so far away, from outside the room?