"60" might have something to do with the board with all the letters on it that you have to read off. Might just mean he couldnt see the smaller letters. Im not 100% sure. Hope this helps.
I took my son for his eye exam and they said I had to take him to his dr. before they could do an exam and get his glasses. She had asked me if my son could see and I said yes. Then she said something about that she had put it on 60 & he still couldn't see. I told her he can see things well, he has an astigmatism. He has not complained about not being able to see the board at school or reading. I don't understand what the lady meant by the 60. I did schedule another appointment with another optometrist to get another opinion. Does anyone have a clue? It really has me worried!!!