"But I don't want to be ugly!"
It was the cry of a despondent six-year old, recently diagnosed as a relatively high-minus myope. She'd been complaining to her mother of headaches and stared with glee through a pair of trial frames; yet when her mother told her it was time to pick out a pair of glasses, the hesitant smile became a brave front became a trembling fear.
After the PD measurement, next up is a temple length measurement. Yes, you need to measure a temple length. You may be able to get away without measuring for it on your average adult, but not with a bouncing 2 year-old.