Reflective Burn (Mirror Coatings)

[jherman]

Can mirror coated lenses redirect sunlight and burn the nostril area?

The only burns I have seen of this sort were from a different wave lengths than UV's.

Had any mystic pizza lately Robert?

[coda]

Can mirror coated lenses redirect sunlight and burn the nostril area?

The only burns I have seen of this sort were from a different wave lengths than UV's.

The short answer is no. The convex side of a mirror lens will not provide enough focusing power to substantially increase radient energy to burn a nose (or any other part of the face) presuming that the energy impinging the face isn't already great enough to cause a burn if unfocused. It could possibly increase the energy enough to result in a higher propensity for a sun burn but only by a factor of about 5%.

[shanbaum]

It's certainly true that the convex reflecting surfaces of mirrored sunglasses won't focus sunlight, but they will certainly reflect some amount of sunlight onto the wearer's nose that wouldn't otherwise be there. I suppose it would be possible to calculate, but that would require thinking real hard and it's too hot outside for that. 5% sounds a little low, but I wouldn't hazard an alternative guestimate.

In any case, my advice is, wear sunscreen.

Haven't been to Mystic in a while, Jimmy. They had a fire there a while back, but I imagine they've reopened.

[jherman]

nmsg

[coda]

5% sounds a little low, but I wouldn't hazard an alternative guestimate.

My 5% guestimate (and it really is just that, I didn't even do any back of the envelope calculations) came from the reflectivity of most ophthalmic mirrors (less than 20%), a presumption of no condensation of the light by the front lens surface, and some degree of motion of the head. I may be wrong but 5% still seems reasonable.

Robert is right, wear sun screen.

[chip anderson]

I have actually seen reflective burns from shinny frames, i.e. gold and silver.

In some situations, the heat collected by frames can contribute, metal can get pretty hot down here.

Chip

[Eddie G's]

I had a couple of "face burn" complaints with the H2optix Sunglasses when they first came out with that blue mirror.

It was very strange.