New materials and chemistry concerned in the most recent generations on the lenses have made significant progress in addressing the 2 basic criteria for selection :
More mature generations (and some present generations) keep a yellow or somewhat jaundiced hue even if not exposed to extremely violet light-weight (indoors as an example). The newest era Transitions are broadly regarded to become the best available and virtually fully obvious inside the absence of ultra violet.
Most more recent photochromatic lenses produce a rapid changeover from gentle to darkish as they may be uncovered to ultra violet - the genuine test as well as the differentiation is the price at which they regress from the darkest tint to very clear. Once more Transitions lenses are extensively thought to be ideal in class in this regard.
Transitions lenses certainly are a broadly held trademark for any certain (newest) generation of materials and technology which might be mixed and sold below the "Transitions" brand. Other (but comparable) names aren't precisely the same, and are generally regarded to be not as very good, as they're from older technology photochromatic technologies.
Ultimately - never count on your photochromatic lenses (regardless of which manufacturer or technology) to make much of a distinction whilst driving, as the windscreen of the auto is developed to soak up many of the UV before it enters the cabin - hence the lenses inside your glasses have absolutely nothing to respond with. Should you need or would really like tinted lenses while driving, you might be much better off getting two pairs on the exact same frame with prescription obvious and prescription tinted lenses.