New supplies and chemistry concerned inside the newest generations in the lenses have created significant development in addressing the 2 basic requirements for choice :
More mature generations (and some current generations) retain a yellow or slightly jaundiced hue even when not exposed to extremely violet light (indoors by way of example). The most recent technology Transitions are broadly regarded to become the top obtainable and virtually totally distinct in the absence of ultra 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 along with the differentiation would be the price at which they regress in the darkest tint to obvious. Again Transitions lenses are extensively regarded as best at school within this regard.
Transitions lenses really are a widely held trademark for any specific (most recent) technology of supplies and technologies which can be combined and sold below the "Transitions" manufacturer. Other (but related) names will not be the identical, and are generally regarded to become not as great, as they're from more mature generation photochromatic technologies.
Ultimately - don't expect your photochromatic lenses (irrespective of which model or technologies) to make considerably of the distinction while driving, as the windscreen of a automobile is designed to soak up many of the UV ahead of it enters the cabin - hence the lenses within your eyeglasses have absolutely nothing to respond with. In case you need to have or would like tinted lenses while driving, you happen to be far better off getting two pairs from the exact same body with prescription obvious and prescription tinted lenses.