Closely associated with intellectual thinkers and politicians, round sunglasses were rarely worn by those noted for their fashion sense – unless you count John Lennon, whose granny style sunglasses were snapped up at auction for an estimated £1million in August 2007.

Several years later, and the circular sunglass is a defining element of celebrity fashion, appearing on the likes of Jennifer Love Hewitt and Kylie Minogue. The Australian pop singer's sunglasses are among our most anticipated trends of the summer. Retro and round, these sunglasses are as fashionable today as they were in the 1960s.

Flattering to men and women Ray-Ban 4140 is a combination of the iconic Wayfarer and Clubmaster models, which defined the look of 2009. A combination of the two, the 4140 has a large frame shape and is more angular than those of the 1960s. With subtle pin detailing and Ray-Ban logos to complete the look, these hot property shades come in a number of ways to choose from including red, white and black and a polarised lens option.

Polarised Ray-Ban models come with an anti-reflective coating for the ultimate in protection. Glare is a light within your field of vision that is brighter than your eyes can comprehend. The result of light waves bouncing off of shiny and reflective surfaces such as water and metal. The anti-reflective coating eliminates glare for clearer and sharper vision, enabling you to see past the white light. Ray-Ban 4140 model black polarised has the letter 'P' directly etched onto the lens to distinguish them from non-polarised Ray-Ban models.

Mary Kate was first seen wearing a pair of round sunglasses at the Sundance Film Festival in 2008, while Lady GaGa has been spotted wearing them all over the place (including her music video Paparazzi). But there is no obvious source for the revival other than being retro, savvy and cool. No longer cool to be square, it's time to downsize from oversized squares and embrace the little round frame.