Paddy at the optician

Paddy went to the opticians.

When he was told to read the card, the optician said "put your left hand over your right eye."

Paddy was looking at his hands and couldn’t tell left from right

The optician said "o.k. put your right hand over your left eye"

Again he couldn’t get it right so the optician said "hold on" and went out the back and came in with an empty cornflake box which he put on Paddy’s head and cut a hole at eye level.

Paddy started crying.

"Now what’s the matter?" said the optician.

Paddy said

Spoiler:

"I wanted a horn rimmed pair like me brother"