vertical diplopia--benign explanations?

[Camcm]

Hello. I am a 48-year-old woman, in good health, with history of allergies and asthma. Sudden onset of intermittent binocular vertical diplopia 8 years ago. At the time, was also experiencing a lot of trouble with allergies: eyes were red,itchy, swollen; I rubbed them excessively. Diplopia happened during early morning vigorous exercise; worse on downgaze and looking to right. I learned to control it and avoid it by tilting my head. After returning home, had bloodwork and brain MRI--all normal. Diplopia occurred off and on over next years,during morning exercise; allergies had subsided. I had TAH/BSO last year, recovered well, resumed morning exercise routine. Also had flare-up of allergies after surgery (itchy eyes; eyelid edema; etc.)Began having diplopia again--almost always only during morning exercise (running) and always controllable. I do not experience it if I run or play soccer later in the day. Also, began having tingling in neck and midback, and deep shoulder pain on right, extending down arm. PCP said these latter symptoms probably from computer use. Referred to neuro; repeat MRI of brain and c-spine and extensive blood tests for everything--all normal. Neuro said right-sided reflexes not as brisk as left ones, but doesn't want to put much stock in that. I will have LP and VEPs this week. I feel so very healthy, though. I can't help but sense some connection between morning exercise, allergies, and the diplopia. Neuro willing to refer me to top neurophthalm. if I wish. What are possible explanations for this diplopia? Don't 2 normal MRIs rule out MS? thanks!

[CCF-Neuro-M.D.-JT]

Please keep in mind that I have never examined you.  But from your description of the symptoms, I wonder if you have a problem with a muscle that controls eye movements called the superior oblique muscle.  Patients often complain of diplopia when looking and down and towards the opposite side of the muscle problem (in your case it would be a left superior oblique problem because you have trouble looking down and right).  To compensate, they tilt their heads the other way ( in your case to the right) but some people tilt towards the side of the problem and then ignore the second image.  You can be born with this or acquire it from a long list of problems, a big one being history of head trauma.  I agree that the 2 normal MRIs make MS less likely and also rule out other more serious diseases such as brain tumor, hemorrhage, or inflammatory process around the nerve going to the eye.  However, other diseases such as myasthenia gravis should be considered. I'm guessing that your workup this week will be normal.  But I highly recommend the neuro-ophtho consult.  They may be able to better characterize the problem.  Good luck.

[Camcm]

sorry, wanted to give a little more info: when diplopia first occurred, I was living in a foreign country; I believe allergies were flaring up because of molds in our house there. Also, my hyst/oopherectomy was because of fibroids--no other issues--and I'm now on estrogen; doing just fine. Am experiencing the diplopia about twice a week now: definitely vertical, with lower image being a little skewed. I cannot make the diplopia happen, but when it occurs, I can resolve it and continue with my workout. Neuro said sometimes no cause for such palsies is found. thanks for any advice!