Need I to configure something on Unity or on my iPhone to increase quality?

I am creating some VR samples and after build the android and the iOS applications I verified that iOS apps is not so good than android apps. I cannot focus my eyes, the image is so blurry and the environment gets a bit deformed. In compensation on android the same sample looks great. I am using cardboard with the iPhone6 and Moto G4.

Thanks in advance.

Bump!

Same issue here… screen distortion looks abysmal on ios. Android though not great is far better.
Also rendering of even the simplest of scenes (literally cubes) results in jarring step ridden rendering (not motion, but rendering) where as Android although blurry is at least smooth.
3 seconds in the viewer is enough to feel you’re doing permanent damage to your eyes, and is unusable.

I’ve used unity 5.6, 2017.1, 2017.2, iphone6, iphone7, iphone8+… none of this works.