surf sunglasses
Anti-Impact Protection on Surf Sunglasses
Anti-Impact Protection
But surf sunglasses are a solid and they can transmit forces much better than liquids.  Surf sunglasses can work like a sail, taking the force of all the molecules across a great area and transmitting it to a smaller area.  This can cause harm, especially if that small area is your nose.
Anti-impact protection is a critical feature of surf sunglasses.  We do not normally think about the impact our face has against the ocean.  If we jump from a height we notice the water smacking against us but we do not think about the force the water puts on our face when we duck dive or fall into the surf.  That is because the ocean is a free flowing liquid and the individual molecules go where they may.  The force of any individual molecule is close enough to nil that unless we hit the water very hard it can cause no harm.
Different Methods of Anti-Impact Protection
Anti-impact protection can come in several forms.  Where and how the glasses sit on the face is terribly important.  If the whole force is distributed solely to the nose – bad news.  Ideally you want the glasses to distribute impact across the whole face, especially to less sensitive areas like just above the nose.  

Foam padding or any soft material that offers “give” will help reduce the dangers of impact.  The total force will be the same but it will be distributed over a longer time diminishing the harm done. Some surf glasses like the Spex Surf Goggle are  made entirely out of soft materials.

Flexible frames are good because they will twist away.  The problem with flexible frames is that they are more inclined to come off – they do not have ridged structure to hold onto the face.  
Spex Goggle offers the best anti impact protection
The Spex Goggle rests across the whole face distributing impact evenly and is made of a soft material.
Why surf sunglasses need anti-impact protection
Force of millions of water molocules on the surf sunglasses
Large force of surf sunglasses on the face
Well designed surf sunglasses offer anti-impact protection
How Important is Anti-Impact Protection?
At the end of the day we are just surfing, we are not getting hit in the face with a hammer.  Serious harm rarely comes from poorly designed glasses.  Do not let this article scare you but if you are interested in knowing, the safest surf goggles are the Spex Surf Goggle, the Costa Rica and the Tierra del Fuego.
Tierra del fuego with removable foam padding
The Costa Rica has foam padding around the inside fo the frame
Tierra del Fuego surf sunglasses with foam  padding is the Surf Sunglasses Super Store