Transient monocular blindness – Amaurosis fugax – Transient visual loss

Ross Hauser, MD

It is very likely that if you are reading or listening to this article you are trying to find some answers to those times when you suffer from a temporary vision loss, or a slow fading out to gray in one of your eyes. It is also likely that this is a problem that currently you and your doctors are at a loss for understanding or treating. For some people, this vision loss or vision alteration has become so frequent that they simply live with it once their tests ruled out cardiovascular, vascular, and neurological disease. But there has to be a cause and possibly an unexplained treatment. In this article, I will present the possibility that cervical spine or neck instability and a diagnosis of craniocervical instability may be the missing diagnosis for the temporary loss of vision or vision disturbances in one eye. There is a connection between neck pain and vision problems.

The people who contact our center are people who usually do not begin the conversation with their temporary loss of vision in one eye. They have many different symptoms and conditions and temporary vision loss is only one of them, and even then, vision loss may not be at the top of the symptom list. That shows us nearly immediately the complexity of their medical history. These people, maybe like yourself, have been on a long medical journey of test after test. For most, the tests did not tell them why this is happening, but, at least the tests have the benefit of telling these people what is not causing their vision problems. The usual outcomes in situations like this are the person receiving more medications, this time for blood thinners, and a recommendation to avoid a high-fat diet. This of course, on top of other medications that they are already taking for their other symptoms. Or as some people say of their medications, “more on the pile.”

Here is are examples of stories we hear, note that vision loss is not even the primary symptom that people are looking for help for. The stories has been edited for clarity.

They probably think I am crazy.

I have a lot of things wrong with me, I can’t breathe, but it’s not my lungs, I cough, have chronic hiccups, my diaphragm does not work right and I am not getting enough oxygen, I have double vision, light sensitivity, temporary blindness, hearing problems, blackouts, and neck pain. I have told my doctors my symptoms worsen when I turn my head. The MRIs come back “showing nothing.” Blood work comes back “nothing extraordinary.” They probably think I am crazy.

The reasons as you may be well aware of is that in some cases, when there is no obvious cause of symptoms, the doctors begin to doubt the symptoms are actually occurring. In the next story, doctors came to a consulsion.

Finally, my doctors got together and gave me a diagnosis of craniocervical instability.

I was in a car accident that resulted in a bad concussion and neck injury, I thought I broke my neck. A few weeks later, out of nowhere, it felt like my neck just collapsed, I had intense pain, it was very scary. I went to the doctors and had an x-ray, MRI, and CT scan. My doctors were not sure if this was a delayed injury from the car accident or maybe I turned my head the wrong way. Whatever happened I was now showing a bulging disc at C5-C6. I could not turn my head. After some muscle relaxants and other medications that helped control the spasms, my head felt like it was going to fall off my neck. Then the symptoms got worse. I have vision problems, the room spins or objects appearing to be moving. One day my left eye went extremely blurry, then dim, then blind. The vision came back almost immediately but that really scared me and I went to the doctor to rule out that I was having a stroke. Now I just accept that it happens. It is just one of the many symptoms I have. Finally, my doctors got together and gave me a diagnosis of craniocervical instability. The problem is now they do not know what to do with me.

Like the example stories above, temporarily loss of vision in one eye is a “mystery symptom,” among many “mystery symptoms.” Its causes can be many, we will focus this article on craniocervical instability.

Transient monocular blindness, Amaurosis fugax, Transient visual loss. Is the problem of vein stenosis caused by the compression of the cervical spine vertebrae?

In many cases, these three terms, transient monocular blindness, amaurosis fugax, and transient visual loss are used interchangeably to describe this temporary loss of vision in one eye. As mentioned, most times these terms are associated with vascular disease, hypertension, high cholesterol, and other risk factors associated with stroke and heart disease. In your medical journey, your doctors probably explored these problems initially and looked for a blockage in a vein or artery caused by plaque build-up that may have lead to the temporary blindness in one eye. This is why this problem can easily be thought of as a TIA (Transient ischemic attack,) or a “mini-stroke”. But what if the vein blockage is not being caused by an internal build-up of plaque? What if the vein blockage is being caused by disc compression?

A paper published in the Neurology Journal BioMed Central Neurology (1) tried to identify why people have this temporary blindness. Here are the summary learning points of this paper

The origin of transient monocular blindness in patients without carotid stenosis (traditionally thought of as cardiovascular disease) has been linked to ocular venous hypertension (poor drainage of the fluid inside the eye), increased retrobulbar vascular resistance (the blood vessels resistance to high/low blood pressure flow), sustained retinal venule dilatation (changes in the diameter and length of the retinal vessels typically associated with diabetes) and higher frequency of jugular venous reflux. (The valves of the jugular vein don’t function properly, leading to a backflow of blood through the valves).
The researchers of this study found that transient monocular blindness patients suffered from significantly more moderate or severe internal jugular vein stenosis compression/stenosis which could impair cerebral venous outflow. They write that their results provide evidence supporting that the cerebral venous outflow abnormality is one of the etiologies of transient monocular blindness.

In other words, there is a back up in the drainage of blood or cerebral venous outflow. If it is not cardiovascular or vascular in nature, it has to be something else.

What is causing the backup? What is causing the buildup of intracranial pressure?

We have an extensive article, Cervical Spine Instability, Vein blockage, fluid build-up, and intracranial hypertension, which helps explain what is causing the buildup of intracranial pressure when it is not cardiovascular or vascular in nature. This article is summarized here in the context of vision problems.

We see many patients who have a serious health challenge in having intracranial hypertension. In many of these people, intracranial hypertension was not initially thought of as a problem as their doctors instead tackled the symptoms that these people were facing. Symptoms included dizziness, headache, vision problems such as sensitivity to light with exaggerated pupillary hippus dilating and constricting which can cause problems with light sensitivity and the pupil fails to respond correctly to light sources. These people also faced symptoms and diagnosis of tinnitus or ringing in the ears, neck pain, and tremors. Some developed the graying out of vision and temporary blindness in one eye.

Once a problem of intracranial hypertension or a build-up of pressure around the brain was discovered, a myriad of tests and treatments were tried. Once obvious causes such as head injury or stroke were ruled out, initial testing may have looked for causes in blood clots, infection, and tumors. Once tests ruled those out as causes your diagnosis of intracranial hypertension, you then got an updated diagnosis of idiopathic intracranial hypertension, which means no one knows why you have intracranial hypertension.

Idiopathic intracranial hypertension, temporary blindness, and problems of drainage in the veins

The back up in the drainage of blood or cerebral venous outflow. If it is not cardiovascular or vascular in nature, it has to be something else. I want to empathize again independent research that suggests something else. That something else here is “backwash,” a problem with the valves of the jugular vein. We are addressing two problems with the jugular vein, stenosis or compression, and a valve problem.

These are the summary learning points of a study published in the journal Cerebrovascular Diseases on “jugular backwash.” (2)

Summary learning points

The frequency of jugular venous reflux (jugular backwash) is higher in patients with transient monocular blindness.
Jugular venous reflux may impede ocular venous outflow, and resulting disturbances in cerebral and ocular venous circulation might be a cause of transient monocular blindness.
- Explanatory note: This explanation comes from the book” The Ocular Circulation. Kiel JW. San Rafael (CA): Morgan & Claypool Life Sciences; 2010. (3)
- Venous outflow from the eye is primarily via the vortex veins (the veins of the eye) and the central retinal vein (the vein that runs through the optic nerve), which merge with the superior and inferior ophthalmic veins (the primary drainage veins) that drain into the cranial venous drainage structures, cavernous sinus, the pterygoid venous plexus, and the facial vein. Ultimately the facial vein drains into the internal jugular vein.
Transient monocular blindness patients have vasculature changes in their retinal venules, and this can be caused by problems of ocular venous outflow, as revealed by dilated retinal venules.
- Explanatory note: What we have here are many symptoms converging together under the umbrella of Transient monocular blindness. We have intracranial pressure, we have dilated retinas, we have a drainage problem
The summary of this research: “These findings provide evidence that frequently occurring jugular venous reflux associated with transient monocular blindness impedes ocular venous outflow, and the subsequent disturbances in ocular venous circulation may be a cause of transient monocular blindness.”

Papilledema

Papilledema is the swelling of the optic nerve of the eye from raised intracranial pressure.
Intracranial pressure occurs because the cerebrospinal fluid that protects the brain, which is constantly produced and replaced, does not drain out properly and the new, fresh fluid that comes in, “overflows,” the inner skull. Fluid pressure builds on the brain, the eyes, the sinuses.

There are many comorbid or simultaneous symptoms and conditions that people with transient monocular blindness suffer from. Here I will focus on Papilledema as part of the progression of a person’s problems with vision difficulties or blindness.

Papilledema type symptoms and conditions are problems we see in many patients. Again, let’s stress that these symptoms and conditions are common to many of the problems we see in patients who have cervical spine instability or craniocervical instability and a clear sign of the complexity of these people’s cases.

The common symptoms of Papilledema are headache, nausea, graying out of the visual field, visual floaters, double vision, pulsatile tinnitus.

The graying out of vision

A December 2020 study (4) explores why some people have the graying out phenomena. Here are the summary learning points of this study:

Idiopathic Intracranial Hypertension is a disease of elevated intracranial pressure without any known cause.
Visual dysfunction is the major symptom of this disease but not much is known about the way the contrast sensitivity (being able to distinguish between varying shades of light to dark, in some patients this ultimately progresses to a field of gray.
Intracranial pressure affects both central (front) and peripheral (side) contrast sensitivity and therapy results in the improvement of contrast deficit. Poor contrast can possibly be explained by relatively more involvement of the Magnocellular pathway over the Parvocellular pathway.
- What this is suggesting is that something is interrupting nerve messaging and creating a neurologic situation.

The clues of cervical spine instability and craniocervical instability

The complexity of this issue cannot be understated. I introduced Papilledema because in some patients it is a point on the journey to temporary blindness in one eye. People report an initial loss of light-dark sensitivity, a gray field, and then the “fade to black,” loss of vision. There is a possible connection between cervical spine instability and craniocervical instability. Another common clue is the idea of the neurologic situation.

If there is vein compression, there is the possibility nerve compression exists as well.

The connection to migraines

In August 2022, doctors presented this case history in the journal Cureus (x):

A 44-year-old male with a past medical history of migraine with aura came to an emergency room with transient vision loss in the left eye, which lasted for two minutes. “A computed tomography scan of the brain was negative for stroke. The patient was treated with intravenous fluid, aspirin, and enoxaparin sodium (an anticoagulant medication) and instructed to follow up with neurology. A medical emergency such as amaurosis fugax caused by ocular migraine must be managed aggressively, and prompt imaging is necessary to exclude other causes.”

In this case, the doctors focused on what it was not, found a migraine connection, then sent the patient for neurological assessment.

In the image below the neck-eye reflexes are described.

These reflexes keep the head balanced while a person is watching moving objects or the body or head is in motion.

The reflex vestibulo-ocular (VOR) causes eye gaze stabilization during head motion
The reflex cervico-ocular (COR) helps the eyes to move in relation to neck rotation, (because of cervical ligament and facet joint proprioceptors – neurons that sense motion.)
The reflex vestibulocollic (VCR) helps to stabilize head in space when the body moves.
The reflex cervicalcollic (CCR) muscles tightened to stabilize head (because of cervical ligament and facet joint proprioceptors – neurons that sense motion.)

Potentially all these reflexes are impaired with ligament cervical instability causing symptoms of vertigo, dizziness, Nystagmus, Oscillopsia, visual disturbance and poor balance.

Vein blockage, nerve compression, fluid build-up, intracranial hypertension, and craniocervical instability

In this section, we will discuss how cervical spine instability and craniocervical instability causes arterial, venous, and nerve compression and how this can impact eyesight and vision challenges.

We are going to start with an introductory video by Ross Hauser, MD. Below the video is a summary of the video with explanatory notes to help further and explain some of the concepts that Dr. Hauser is putting forth in explaining vision problems as they relate to neck pain.

Summary learning points

Dr. Hauser emphasizes that to understand the impact on symptoms of cervical neck instability causes, including ultimately vision problems, you have to understand that the nerves that travel the spine are so intertwined with each other and through the cervical vertebrae that any compression to the nerves will cause far-reaching problems.
At 1:30 of the video: Dr. Hauser talks about C1-C2 instability and its impact on the Vagus Nerve (Cranial Nerve X)
- When the Vagus nerve is injured by compression caused by instability at C1-C2, this can cause vasospasms (narrowing of the arteries and reduction of blood flow). If these vasospasms impact the ophthalmic artery, the artery that supplies blood to the eye and eye area including the orbit – this can lead to some of the symptoms are patients describe to us such as darkening, black spots, or grayness in the vision of one eye.

At 2:00 Minutes of the video, Dr. Hauser refers to this slide:

In this image, vision problems caused by cervical spine instability is connected to Diminished ocular blood flow, Exaggerated pupillary hippus dilating, Hampered accommodation or human ocular accommodation mechanism or accommodation reflex, Increased intraocular pressure or elevated intraocular pressure, Limited pupillary constriction, Optic nerve damage. Here are brief explanatory notes:

Diminished ocular blood flow can cause symptoms, usually in one eye, blurred vision or partial or complete loss of vision
Exaggerated pupillary hippus dilating and constricting can cause problems with light sensitivity and the pupil fails to respond correctly to light sources.
Hampered accommodation or human ocular accommodation mechanism or accommodation reflex. This is the function of the eye that maintains a clear focus on objects whether close by or far away.
Increased intraocular pressure or elevated intraocular pressure. This is high pressure inside the eye is caused by an imbalance of production and drainage of the inner eye fluids. The symptoms here include various vision disturbances. Researchers speculate a connection to the development of glaucoma.
Limited pupillary constriction. This is also a problem with the dilation of the pupil. Your eye may not respond properly or at all to light stimulus.
Optic nerve damage caused by blood flow restriction.

A swollen optic nerve

We see in some patients with vision problems that relate to a problem of cervical spine instability, a swollen optic nerve. A paper in the journal, Practical Neurology (5) describes problems of a swollen optical nerve in this way:

“Patients with abnormal visual function most likely have demyelinating optic neuritis (swelling of the nerve sheath and optic nerve) or non-arteritic anterior ischaemic optic neuropathy (loss of blood flow to the optic nerve). . . ”

These are characteristic symptoms of compression or entrapment of the nerves and arteries in the cervical spine. One tool that we use to assess problems, especially swelling, of the optic nerve, is to take the nerve’s measurements to check for swelling via ultrasound. The test is illustrated below:

In this photograph, an optic nerve measurement is taken via ultrasound. We are looking for swelling of the optic nerve that may explain vision problems by way of demyelinating optic neuritis (swelling of the nerve sheath and optic nerve) or non-arteritic anterior ischaemic optic neuropathy (loss of blood flow to the optic nerve). Characteristic symptoms of compression or entrapment of the nerves and arteries in the cervical spine.

In this ultrasound image, the swelling of the optic nerve is clear compared to a normal optic nerve. A common but not as commonly diagnosed cause of swollen optic nerve and problems of vision is increased intracranial pressure from cervical spine instability.

In the video below Ross Hauser, MD, and Danielle Matias, PA-C discuss the common visual and cognitive symptoms due to increased intracranial pressure regularly seen in our center.

Ross Hauser, MD: We are finding and doing outcome research on is the problem of what’s causing the cerebrospinal fluid flow to accumulate and cause pressure inside the head to be elevated is a venous obstruction (vein blockage) so how does venous obstruction occur in a neck? One way is stenosis because of an elongated stretched out vein.

The main danger of brain venous congestion is that it increases intracranial pressure, this pressure is then transmitted to the brain’s arteries, which then increase blood flow to ensure adequate oxygenation of the brain. If the blood vessels cannot respond because of their obstruction in the neck, then brain ischemia can ensue.

The possibility that cervical spine or neck instability and a diagnosis of craniocervical instability may be the missing diagnosis for the temporary loss of vision or vision disturbances in one eye.
Regenerative Medicine Injections

No, these are not injections into the eye. These are injections into the cervical spine to help correct the problems of cervical spine instability and craniocervical instability.

Part of our treatment program is a focus on cervical spine ligaments. The ligaments are the strong connective tissue that holds the vertebrae in place. When you have a slipped disc, a pinched nerve, a herniated disc or nerve, the underlying problem is that the vertebrae are compressing these structures and causing pain and possible neurologic type symptoms. When the cervical spine instability is great enough or even focused enough on a certain neck segment, it can also cause compression on the arteries and veins that travel through and around the cervical vertebrae.

Prolotherapy is an injection technique that stimulates the repair of unstable, torn, or damaged ligaments. In 2014, we published a comprehensive review of the problems related to weakened damaged cervical neck ligaments in The Open Orthopaedics Journal. (6) We are honored that this research has been used in at least 6 other medical research papers by different authors exploring our treatments and findings and cited, according to Google Scholar, in more than 40 articles.

In our clinical and research observations, we have documented that Prolotherapy can offer answers for sufferers of cervical instability, as it treats the problem at its source. Prolotherapy to the various structures of the neck eliminates the instability and the sympathetic symptoms without many of the short-term and long-term risks of cervical fusion. We concluded that in many cases of chronic neck pain, the cause may be underlying joint instability and capsular ligament laxity. Furthermore, we contend that the use of comprehensive Prolotherapy appears to be an effective treatment for chronic neck pain and cervical instability, especially when due to ligament laxity. The technique is safe and relatively non-invasive as well as efficacious in relieving chronic neck pain and its associated symptoms.

Prolotherapy is an injection technique that stimulates the repair of unstable, torn, or damaged ligaments. When the cervical ligaments are unstable, they allow for excessive movement of the vertebrae, which can stress tendons, atrophy muscles, pinch on nerves and cause other symptoms associated with cervical instability including problems of vision.

Actual Prolotherapy treatment

This video jumps to 1:05 where the actual treatment begins.

This patient is having C1-C2 areas treated. Ross Hauser, MD, is giving the injections.

In 2015, our research team published our findings in our paper “The biology of prolotherapy and its application in clinical cervical spine instability and chronic neck pain: a retrospective study.” This peer-review research was published in the European Journal of Preventive Medicine. (7)

Here we wrote: “In an effort to facilitate the diagnosis and treatment of clinical cervical spine instability and chronic neck pain, we investigated the role of proliferative injection Prolotherapy in the reduction of pain and recovery of constitutional and neurological symptoms associated with increased intervertebral motion, structural deformity and irritation of nerve roots. . . 95 percent of patients reported that Prolotherapy met their expectations in regards to pain relief and functionality.”

An individualized treatment protocol may include the following:

A certain number of Prolotherapy visits to resolve the instability.
Chiropractic consultation and treatment
An initial period of cervical immobilization with a cervical collar in order to limit neck forces while the ligaments regenerate.
Rescanning every two visits to ensure the Prolotherapy is resolving the instability.
When improved spinal stability is demonstrated, Caring Cervical Realignment Therapy using cervical weights will be started. In some severe spinal curves, CCRT using cervical weights is started immediately. Changing the spinal curve can take just minutes for some patients to several months in others.

The treatment regimen is continued until the person can do all desired activities with minimal symptoms and spinal curve kinematics (curve) are improved.

Our goal is to provide long-term solutions. Through extensive research and patient data analysis, it became clear that in order for patients to obtain long-term cures (approximately 90% relief of symptoms) the re-establishment of some lordosis, (the natural cervical spinal curve) in their cervical spine is necessary. Once spinal stabilization was achieved with Prolotherapy and the normalization of cervical forces by restoring some lordosis, lasting relief of symptoms was highly probable. As with any medical technique, the treatment will not work for everyone. We provide a detailed prescreening process to help assess the ideal candidates for treatment.

Ask for help and information from our specialists

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