Use ‘Iris Blur’ to Add A Region of Focus In Your Image:
A quick and easy way to bring selective focus to your image is to use Iris Blur (Filter/Blur Gallery/Iris Blur). In the 1st Screenshot you will see the Blur Gallery interface: adjusting the position and size of ‘iris’ region will affect the blur outside. You can adjust the strength of the blur. Screenshot 2 shows the original image with no selective blur.