optic neuritis

During exercise I have patches of reduced vision around the center of my visual field, these are always in the same place. They occur sometimes when I am not exercising, but not very often, and sometimes during exercise after a certain length of time they disapear, they resemble the glare when you look into the sun, and are most notable if I have been looking towards the ground and then look at the sky and blink, I have read about uhthoffs symptom and worry that this may be the case. I have had these symptoms for around seven years and have had various blood tests for sugars and cardio tests, carotid artery scans and so on, as well as being seen by an othalmologist on two occasions, but none of these were conclusive, the only thing that seems to match my symptom is uhthoffs, I have osteoarthritis in the neck, but otherwise am in good health. I believe but am not sure that Uhthoffs symptom goes away as the body cools down so am somewhat confused if this is the case, why it dissapears sometimes when I am exercising and therefore not cooled down, I would greatly appreciate any response to this question.

[Neuro Forum]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.

Without the ability to examine you and obtain a history, I can not provide you with a diagnosis. I can not tell you whether or not you have Uthoff's but as you mentioned, if your symptoms occur when you are not exercising or over-heated, this is not entirely consistent with this phenomenon, and there are several other causes of transient visual obscuration.

You are correct that stereotyped vision obscuration occurring with over-heating such as exercise may be a sign of Uthoff's phenonmenon, which is worsening of a pre-existing neurologic deficit with overheating. When the sheath of material that coats nerves called myelin is damaged, electric conduction along the nerve is impaired, and with overheating, conduction slows even further, causing symptoms.

As I mentioned, Uthoff's phenomenon is classically seen in demyelinating disorders i.e. those that affect myelin. These include several conditions, but one that commonly affects the eye is called optic neuritis. Optic neuritis is an inflammation of the optic nerve, the bundle of fibers in your eye that transmits information to your brain. Symptoms include pain in the eye and vision loss. Color vision loss can also occur. Optic neuritis may be viral, may have no known cause, or may be a manifestation of multiple sclerosis. Most people who have one episode will recover their vision. If you have ever had optic neuritis, you would in all likelihood had some symptoms. While eye exam may be entirely normal, another test, called the visual evoked potential, which gives information as to how long electricity takes to move along the nerve, will be abnormal and will point to the diagnosis.

Other causes of optic neuropathy, or problems with the optic nerve, that are not
demyelinating, can also cause a Uthoff's type phenomenon.

There are multiple other causes of transient visual obscuration, one of which is transient ischemic attack, or TIA, whereby a small artery to the retina gets clogged with clot. This is a sign of increased risk of stroke. This is more likely in people older than 50 with diabetes, high cholesterol, high blood pressure, or other factors that increase risk of stroke. In patients older than the age of 55, a type of inflammation of one artery in the head called the temporal artery, a condition called temporal arteritis needs to be ruled out.

I suggest you have continued follow-up with your regular internist/family physician/primary care doctor. Share your concerns with him/her and describe your symptoms. He/she can evaluate you and decide whether or not these visual changes are TIAs or something else, and can decide if you need referral to a specialist such as a neuro-opthalmologist, which is an opthalmologist specialized in neurologic causes of eye problems, or a neurologist.

Thank you for using the forum, I hope you find this information useful, good luck.

[earl77]

Thank you very much for your reply as I know how busy you must be, thanks Earl.