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.
While the average pair of prescription eyeglasses costs less than $200, a pair with photochromic lenses could cost $400-$650 or more. And pre-made, non-prescription safety glasses or sunglasses with photochromic lenses can cost as much as $200-$400. For example, at EyeGlassLensDirect.com, prescription photochromic lenses cost about $100-$450 per pair, not including the frame, which could add several hundred dollars to the total cost.