I was too busy trying to explain about the eye pain from the meds, I guess I forgot you asked about the eye pain from the O.N.! lol
Eye problems I've had when the O.N. is bad, is usually pain behind the eyes and around them, and often blurry vision and sensitivity to light when the pain is bad, much like a bad migraine does, I suppose. I get the light sensitivity and blurry vision often, but it's not permanent, it comes and goes, depending how bad the pain is.

~Jaime~