A window to the brain
It is often said that “the eyes are the windows to the soul,” meaning a person’s emotions, and perhaps even their thoughts at times, can be understood by looking into their eyes. For neuro-ophthalmologists, this isn’t too far from the truth. Rather than acting as windows to the “soul,” the eyes often act as windows to the brain and nervous system.
The rear portion of the interior of your eye is covered in a layer of nerve tissue known as the retina, which, in turn, sends projections known as axons that form the optic nerve. The optic nerve, a thick bundle of more than 1 million axons, carries visual inputs directly to the brain. The retina and optic nerve are, essentially, a conduit to the brain, allowing for direct visual examination, which can also provide a view into the patient’s nervous system as a whole.
What is a neuro-ophthalmologist?
Neuro-ophthalmologists undergo extensive training to develop the necessary skillset to evaluate patients from neurological, ophthalmic, and medical perspectives. Board-certified neuro-ophthalmologist Moe Hein “Harry” Aung, M.D., in UT Medicine’s Mitchel and Shannon Wong Eye Institute, is one of the very few neuro-ophthalmologists in Central Texas.
Aung is a part of the Mitchel and Shannon Wong Eye Institute care team which includes fellowship-trained ophthalmologists with expertise across a variety of subspecialties. The Mitchel and Shannon Wong Eye Institute care team will also interface with clinicians across other UT Medicine practices, such as neurologists who are a part of UT Medicine’s Mulva Clinic for the Neurosciences care team and health social workers who are a part of UT Medicine’s Health Social Work care team, to provide comprehensive, whole-patient care.
As an ophthalmologist, Aung is trained to conduct comprehensive eye examinations. As a neurologist, he has an expert understanding of the brain as well as the complex systemic diseases and conditions that can impact the central nervous system and cause vision loss or issues with the muscles that control eye movement.
Who do neuro-ophthalmologists treat?
“Around seventy percent of the time, I’m seeing patients who have been referred to me for a consultation,” said Aung. “In those cases, the ophthalmologist or the neurologist suspects a neuro-ophthalmic condition, and they request my opinion about the diagnosis and/or treatment.”
“For the remaining thirty percent of my time,” said Aung, “providers often refer patients to me with the expectation that I will assume the patient’s ongoing care. An example of this is seen with idiopathic intracranial hypertension. It’s a disease where we do not yet fully know the underlying mechanism, but it commonly occurs in young women of reproductive age with recent weight gain as a major risk factor. For unclear reasons, possibly hormonal changes that can come along with weight gain, patients develop increased pressure in their brain, causing the optic nerve to swell, which can lead to vision loss.” IIH is treated with medications and an emphasis on weight loss to lower the pressure in the patient’s brain so that the optic nerve swelling will improve and ultimately disappear.
Another condition treated by neuro-ophthalmologists is myasthenia gravis, which is characterized by rapid muscle fatigue and weakness and is caused by problems in the communication between the body’s nervous system and the muscles. While myasthenia gravis can affect muscles throughout the body, it commonly manifests in the eyes with symptoms such as double vision and droopiness in one or both eyelids.
Multiple sclerosis can also be detected and evaluated by neuro-ophthalmologists. MS is a chronic disease of the central nervous system affecting more than 2.8 million people globally. MS prompts a patient’s immune system to attack the body’s own nervous system, degrading the body’s myelin that provides protective insulation for neurons. This causes multiple debilitating symptoms, including fatigue, loss of motor function, cognitive dysfunction, ongoing tissue inflammation and pain, vision loss and more, depending on the amount of nerve damage that exists and which nerves are affected. A common manifestation of MS is optic neuritis, in which the myelin coating of the optic nerve is damaged.
“It is amazing that with all the major therapeutic advances in the management of MS, we can reduce recurrences and/or slow the progression of MS,” said Aung. “When a patient suffers from optic neuritis, we can treat them first with high-dose steroids during the acute phase. But then, for long-term prevention of recurrence, there are multiple targeted immunosuppressive therapies available for patients now, ranging from monthly injections and daily oral formulations to intravenous infusions every six months to help minimize the immune system from attacking the optic nerve and the central nervous system as a whole. I work closely with our amazing neurology colleagues in UT Medicine’s Multiple Sclerosis and Neuroimmunology Center to care for these patients.”
What should patients expect at an neuro-ophthalmology appointment?
A visit to a neuro-ophthalmologist such as Aung can be characterized as a highly detailed, extensive ophthalmologic exam. Patients can expect to be given a fundus exam in which the eyes are dilated to widen the pupils, the black dot in the center of the eye, to provide the clinician a better view of the retina and optic nerve.
“My exams are very similar to what any patient visiting an eye doctor has experienced but are tailored more toward looking for potential neurological causes of the patient’s symptoms,” said Aung. “I’ll typically perform tests for color vision because, with optic nerve injuries, the color vision will often be diminished first.”
“I also look more carefully at the pupil,” said Aung. “There are pupillary changes that can provide clues when there’s an optic nerve injury. After I dilate the pupils, I’m mainly focused on figuring out whether the changes in a patient’s vision can be explained by potential injury to the optic nerve(s) or the brain. If I don’t see a definite neurologic cause for the patient’s vision loss, then I will also evaluate to see if the underlying cause could be coming from the eyes, such as is the case with corneal surface disease, cataract formation and/or retinal pathologies.” For patients whose vision problems are diagnosed as connected to neurological issues, further examinations, blood work and imaging, such as MRI scans, may be ordered.
