Open/Close Eye animation - Fall asleep/Waking up

How can I achieve an effect like this? it’s very used when a character fall asleep or wakes up and then the eye blinks and the view is not focused. Better with a camera or a cinecamera? Which parameters I’ve to use?
See the video from minute 3.35 to 5.10

You could prerender the blinking and then render it with the HUD.

If you want your camera view distord/ unfocused image, try to play with the camera’s Depth of Field, under Lens category. Document can be found here: Depth of Field | Unreal Engine Documentation
For the blinking part, you could either follow Goanna suggested, or use the Camera fade function, Get Player Controller->GetPlayerCameraManager->StartCameraFade, set to alpha 1 and from alpha 0 if you want the screen to go dark and vice versa, duration is how much time for the fade to complete.
All those thing, you could either use a camera or a cinecamera, in my experience, not much different between those 2 if you only want to implement these functions.