New materials and chemistry concerned in the most recent generations on the lenses have produced important development in addressing the 2 fundamental standards for choice :
More mature generations (and a few present generations) keep a yellow or somewhat jaundiced hue even when not uncovered to extremely violet mild (indoors for example). The newest generation Transitions are widely regarded to be the most effective accessible and practically completely distinct in the absence of extremely violet.
Most more recent photochromatic lenses create a rapid transition from light to dark as they may be exposed to extremely violet - the real test and also the differentiation may be the rate at which they regress from the darkest tint to clear. Once again Transitions lenses are extensively thought to be best in class within this regard.
Transitions lenses certainly are a broadly held trademark for any specific (most recent) technology of supplies and technologies which can be combined and offered beneath the "Transitions" manufacturer. Other (but comparable) names usually are not exactly the same, and therefore are generally regarded to be not as great, as they're from older era photochromatic technologies.
Lastly - do not expect your photochromatic lenses (no matter which manufacturer or technologies) to create much of the distinction while driving, as the windscreen of the auto is developed to absorb a lot of the UV before it enters the cabin - hence the lenses inside your eyeglasses have practically nothing to respond with. If you want or would like tinted lenses even though driving, you happen to be greater off acquiring two pairs from the identical frame with prescription obvious and prescription tinted lenses.