The correct spark plug and gap is crucial to proper ignition. Spark discharge is a breakdown in the air insulator between the electrode and ground. Yes - air is an insulator, a pretty good one at that. As voltage builds at the electrode, atoms in the air within the air gap gain electrons. This process is called ionization.
It's one of the reasons why our standard lenses are polycarbonate (thinner than standard lenses typically sold by other eyeglasses retailers). At Warby Parker, you can upgrade to high index lenses for an additional $30 whereas it typically costs $60 to $100 more.
The price of the glasses at lenscrafters depends on the frame and lenses you choose. And the price of eyeglasses frame ranges from a few dollars to hundreds of dollars. As for the price of lenses, I heard that you may possibly to got a pair of plastic CR-39 no coatings Single Vision lenses around $80.