 Yeah, they're very effective. So like say with like an esotropia where that eye is turning in and they have lots of farsightedness. So we can actually give them glasses and sometimes even like bifocal glasses when they're young because we're trying to stop their focusing. And by stopping their focusing system, we're actually stopping the eyeballs from converging. So we can oftentimes eliminate the strabismus if it's an esotropia because we're eliminating their accommodative function.