Goggle Glasses

                 Gradient lenses 

Gradient lenses go from a darker shade at the top to a lighter one at the bottom, so there will be more protection from sunlight the higher one looks through the lens, but the lower one looks through the lens, the less protection is offered. An advantage is that one can wear them indoors without fear of tripping over something and also allowing the user to see. Wearing sunglasses to nightclubs has become common in recent times, where the gradient lens comes in handy.
Gradient lenses may also be advantageous for activities such as flying airplanes and driving automobiles, as they allow the operator a clear view of the instrument panel, low in his line of sight and usually hidden in shadow, while still reducing glare from the view out the windscreen. The Independent (London), has also referred to these style of sunglasses as the Murphy Lens.[24]

Double gradient lenses are dark at the top, light in the middle and  dark at the bottom.

Gradients should not be confused with bifocals and progressive lenses. 

Flip-up sunglasses

Flip-up sunglasses add the benefits of sunglasses to corrective eyeglasses, 
allowing the wearer to flip up the tinted lenses for indoor use. An alternative are clip-on glasses.