Silverfish has multiple styles with leashes, as well as with removable straps.
http://www.silverfish.com/

Silverfish hands down has the best sunglasses for kite boarding. I have tried most of their styles, but like the Whistler and Road Trip the best. They come with a leash in addition to a strap.
http://www.silverfish.com/

SeaSpecs and Silverfish use a patented frame design which I think deals with ventilation and eyelashes hitting the lenses better than the other similar styles. Flexible, non-rigid style frames have more give and therefore can fall off easier in a wipeout. The same goes for an elastic strap. Silverfi...

Flexible frames fall off constantly because they have too much give. The same is true for goggles with elastic bands.

I have tried quite a few different brands and styles.

The best product out there is Silverfish's Whistler frame. http://silverfish.com/optimizer/product/S1001.html

Oz, You refer to the "snow ones", yet all of Silverfish's sunglasses are designed for the water. You are getting confused because http://www.silverfish.com has so many options, not just the one style that most others carry. Also, Silverfish has special nose pieces on two of their styles that offer b...

http://www.silverfish.com has great kitesurfing sunglasses that come with a leash which few others have - that way it is nearly impossible to lose them.

Go with the company that has been doing these type of sunglasses since 2002 and has multiple options: http://www.silverfish.com

They can also do a much larger range of Rx.

Silverfish sunglasses are an excellent choice for protecting your eyes. They come in 3 different frame styles and can do any Rx. http://www.silverfish.com

http://www.silverfish.com has a wide range of frames that take a wide range of prescriptions.

Another option is silverfish sunglasses. They have many styles. http://www.silverfish.com/