I noticed this a week ago. I first thought it was hail damage that I didn't notice from a early spring (It hailed for several minutes, nothing huge (or dent causing) but a LOT of marble size stuff). I talked to a guy at a collision shop and he said lenses crack like this sometimes, that its not hail. Cracks are what this is. Mostly outside with a few that appear to be inside. This isn't yellowing or hazing. I've restored headlights on cars. This is hundreds of tiny cracks... only on the upper part of BOTH lenses (the upward sky facing part). Has anyone with direct experience seen this before?

 

It looks like it had one those " eye lids" over time the heat created stress marks.

 

No the cars never had eyelids. No films either.

 

I've heard of this before. The guy is right

 

I was going to suggest posting in S2000 Body and Paint which I thought might get you some better responses, but that category doesn't present an *exact* match for this topic either.

Well, if you don't get much helpful responses here, try over there. I can move the thread for you so that it retains the existing responses if you want me to. Just reply here.

 

Had a cover over it of some type.

Or brutal UV!

 

I saw a pair of headlamps being sold in the Classifieds Forum a few days ago with the exact same condition. The seller called them heat cracks, iirc.

 

It's called crazing, which is usually the result of high temps.

 

Crazing like this can also come from cleaning the headlights with any type of solvent, ammonia or alcohol.