Half of vision loss in one eye what's wrong

My right eye has peripheral vision loss

You need to see an Ophthalmologist

Get to an optician or doctor or a/e  immediately.  It could be any one of several things but needs attention NOW.  Your eyesight is precious and you must never neglect any sight loss.   It doesnt have to be painful to be serious.

How old are you? do you have any known eye problems such as glucoma ? Are you suffering from uncontrolled diabetic or hypertension? Did you seek any medical advice regarding your vision loss?? Dont ignore this condition because you may end up losing your whole sight. 

I lost some peripheral in my right eye.so damn scary. They do an mri to make sure no tumor present. Then they watch it. Optic nerve issues and or angle issues. An opthamologist would see pallor nerve but supposedly optic nerve doesnt regenerate. see an opthamologist or a nuero opthamologist.