Goggle Color

Amber Lens
An Amber lens provides excellent vision in both high and low light environments. In low level light (indoor swimming pool etc) amber lenses amplify the light meaning clearer vision. In high light levels (bright sunshine, outdoors etc) they reduce glare which also helps to provide better vision. An ideal lens colour for all environments.

Clear Lens
Clear lens provides a natural light, which makes it ideal for low light, overcast conditions where maximum visibility is required. Clear lens is also ideal for consistent lighting as it provides accurate vision without filtering out colour. Ideal for indoor pools and dark conditions.

Blue / Violet Lens
These colours are designed to allow a moderate level of light into the eye but they still provide some protection from glare. Its a practical colour for changing conditions. Ideal for everyday events and training.

Smoke Lens
Dark lenses provide protection from high light levels (direct sunshine and bright conditions). They have the same principles as sun glasses. Ideal for swimming out in the sun.

http://www.simplyswim.com/docs/ChoosingGoggles.aspx#car2

Blue lenses make it hard for me to pick out the sighting buoys.  I use clear if it is overcast and a smoke mirrored if it is sunny.

I always use a clear or close to clear goggle frames.

I use tinted lenses for all my OW swims here in Miami and clear lenses for my night pool swims.

I buy two pair and then swap the lenses, so that one eye is blue and the other red.

that way- I see everything in 3D!  

but on a more serious side- I just buy the smoke lenses for outdoor, which is where I do most of my swimming - either outdoor pool or OWS.  I do get the 'optical' goggles for my nearsightedness- so I can actually see (yay!).  It's so cool that you can now buy them so cheap these days.

I wear blue in the pool to help with the glare.  Clear for races to help with visibility and sighting.

Mark