Google Cardboard 0.6 SDK becomes blurry on iOS devices

Goodday.

I am using the 0.6 Google Cardboard SDK in Unity 5.3 . When I publish apps to Android device this works perfect (Note4 & S6).

However when I start using the SDK for iOS (iPhone5 & 6S) the images look very blurry. When I make the physical distance between the phone and lenses the image becomes sharp again. Is there a variable of the Google Cardboard SDK that I should change for iOS?

Looking at it for quite some time now, but nothing seems to fix is and also cannot find anything on the internet about this.

Does somebody know what to do? Thanks in advance for the help!!

Kind regards,

Adriaan

PS
As a test I did a clean install of the Google Cardboard Demo Scene. The same problem seems to occur in this app, so definitely is not because of my app.

 

In the Android API Reference the following parameter is available:
float getVerticalDistanceToLensCenter()

Is there something like that in the Unity Google Cardboard SDK?