It would be a second opinion because it sounds like neither you nor your present ophthalmologist have a good explanation for the severe pain.
JCH MD
My ophthalmologist already did a complete exam, measuring eye pressure, protrusion, etc. I also had a vision exam and my prescription for reading distance has changed by 30% which is causing eye strain. I will be getting new glasses. The MRI was completed to ensure there wasn't substantial swelling/enlargement of the extraocular muscles that could have been putting pressure on the optic nerve. This kind of swelling is common with Graves/Exophthalmo. The tests didn't show any substantial muscle enlargement that would cause the severe pain according to the doctor. What would an orbital-oculoplastic surgeon or neuroophthalmologist see from the MRI that my doctor wouldn't have seen?
Severe pain is unusual with Graves. I would suggest you ask your present ophthalmologist for a second opinion either from an orbital-oculoplastic surgeon or a neuroophthalmologist.
JCHMD