The MRI or MRA would likely not show the type of damage that you may have. It sounds like you have possibly the combination of chronic glaucoma with a pale, ischemic, weakened optic nerve ALONG with a worsened circulation, worsened optic nerve health which occured around the time of your cataract surgery. You may even have had ischemic optic neuropathy which may be related to poor microcirculation (yes, definitely worsed by high cholesterol, smoking, hypertension.) Glaucoma in many cases has a circulatory component and the blood flow in the small vessels may be compromised for many reasons adding to the pressure effect and the possible congenital weakness of the nerve to begin with in certain individuals. It's quite complicated, but I'm sure your ophthalmologists will have a handle on it.
Is ischemic optic neuropathy measurable/ diagnosable or is it an inferred condition from other observations/symptoms? If treating my "high" cholesterol with statins or other medications is definitely conclusive, I would use it to possibly "save" the other eye; if not, I am very reluctant to use this type of treatment because of the definite side effects (liver problems, future cancers, etc.) observed in research by Ravnskov et al. Again, thanks for your advice and info.