I tried this code on an image to blur it ... using TViOS 10.1 and Swift 3.0
let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.extraLight)
let blurView = UIVisualEffectView(effect: blurEffect)
blurView.frame = CGRect(x: 256, y: 128, width: 1024, height: 512)
self.view.addSubview(blurView)
With this result... sorry this is not a blur... I am missing something here?