New materials and chemistry concerned inside the most current generations in the lenses have created substantial development in addressing the 2 fundamental criteria for choice :
More mature generations (and a few present generations) retain a yellow or slightly jaundiced hue even if not uncovered to extremely violet light-weight (indoors for instance). The most recent era Transitions are broadly regarded to be the most effective obtainable and virtually totally clear within the absence of ultra violet.
Most more recent photochromatic lenses produce a speedy transition from light to darkish as they may be exposed to extremely violet - the true check along with the differentiation may be the rate at which they regress in the darkest tint to very clear. Once more Transitions lenses are extensively regarded as best in school in this regard.
Transitions lenses certainly are a widely held trademark to get a particular (newest) generation of components and technology which can be combined and offered under the "Transitions" manufacturer. Other (but equivalent) names will not be the same, and therefore are normally regarded to be not as excellent, as they are from more mature era photochromatic technologies.
Finally - never expect your photochromatic lenses (irrespective of which brand or technologies) to produce a lot of a distinction whilst driving, because the windscreen of the car is developed to soak up most of the UV just before it enters the cabin - hence the lenses within your glasses have absolutely nothing to react with. In case you want or would like tinted lenses although driving, you're greater off obtaining two pairs on the exact same frame with prescription very clear and prescription tinted lenses.