Transition lenses, they are one of the more influential developments to hit the eyewear industry in the last several decades. Transition lenses are the ideal combination of prescription glasses and sunglasses, clear at night or when it is cloudy or shady, dark when outdoors in the sun.one pair is all it takes to cover all light conditions. One of the primary drawbacks of transition lenses: they do not fully darken inside a car. UV light present in a car is that which filters in through the side window glass, and usually it's not enough to trigger transition lenses. This can be problematic for many, as daytime driving is one those activities where sunglasses are most useful. Options, such as sunglasses that fit over or clip on to your prescription glasses, are available.