The muscles that control the eyes are of a type the relies mainly on glucose/glycogen for energy; when these muscle start running out of their source of energy they won't work as well and so your vision goes blurry.
So the bad news is that yes, it will probably reoccur, because the entire point of this diet is to use up all your glucose and glycogen stores in order to put yourself into ketosis.
The good news, however, is that after a few days the eye muscles will start being able to use the ketones more effectively for energy and you should notice your symptoms getting better.
In other words, stick with it: it'll get worse before it gets better.
Though of course, if it just keeps getting worse then you should probably go see an optician!