What are the best eyeglass lenses that change to dark shade ?

[Duryea]

Photochromic,Transitions,Glass ,Plastic .I dont want heavy glass and one that change CLEAREST indoor and VERY DARK outside.WHich is best. Do they already have UV protection, ANTI-glare protection and scratch protection or do you pay extra for each protection. Can anyone simplfy this and help me get whay IM looking for and not pay extra for features that are already on the lens. Also what is CRISAN.

[Durham]

Personally, I would recommend transition glasses which is one of the few photochromic lenses. They have a special chemical in the lens which can change the color if they are exposed to UV rays. If you take them outdoors in a bright sunshine, they will become dark automatically and they can return to clear if you are indoors again. So you can wear transition glasses just like sunglasses when you are outdoors.