I don't think anyone thinks of hearing aids as impulse buy items. Not sure where this idea even came from. I sure as heck didn't read it in any post. I guess, because the vision center is at the front of the store, eyeglasses are impulse buy items, too.
Hearing aids and eyeglasses sure as heck don't equate to chewing gum and chocolate bars and they sure aren't stuffed into little boxes at the cash registers. "Front of the store" doesn't mean in the cash register area. Vision centers are at the front of the store and cash registers are at the front of the store because that's the way the stores are laid out. Where's the connection between the two?