First of all if it was a serious disease you would expect over 3 years for other symptoms to develop. Second its not typical at all of an eye problem. 3rd. If you and your family want to pursue looking for a medical cause I suggest you head for a world class tertiary referral center such as Mayo Clinic, Cleveland Clinic, Washingting U in St. Louis, Emory in Atlanta. 4th since you were helped by clonazepan which is for anxiety and panic you should be under the care of a psychiatrist especially with your morbid thoughts.
Sounds like migraine headaches to me. See your family doctor and ask for Imitrex and see if that helps and if not, see a neurologist for a headache evaluation.