What Is Ocular Migraine?

Introduction

A lot of people struggle with headaches throughout their lives. Some may experience the pain more intensely than others. Does this sound like you? Have you ever wondered if what you are experiencing is a cluster headache, a tension headache, or a migraine? In this article, we are addressing a type of migraine known as ocular migraine (OM). OM is also known as retinal or visual migraine; it is an infrequent cause of transitory visual loss in one eye.¹ 

In order to treat patients appropriately and prevent needless testing, it is important for health professionals to understand ocular migraines and identify them.¹ This can save patients time and money, as well as help them to lead healthier and better lives. So let us discuss what is OM, how to detect it and how to treat it. 

Understanding migraines

A frequent illness called migraine is defined by recurring headache attacks coupled with symptoms like nausea or vomiting and sensitivity to light, sound, and smell.² Migraine was initially identified by Galezowski in 1882 as central retinal artery thrombosis that happened during sudden episodes of vision loss. However, there is still much debate over the categorisation, nomenclature, aetiology, and management of migraines.^1,3,5 

About 15% of the general population suffers from migraines, making it the third most frequent illness in the globe for both sexes. There are two primary subtypes of episodic migraine: migraine with aura (MwA) and migraine without aura (MoA).² 

In addition to episodic migraine, chronic migraine (CM) has a significant impact on the patient's quality of life and is a global social burden. Although experts are still at odds on the exact cause of migraines, the neurovascular system appears to be the primary player. The trigeminal vascular system (TGVS), which controls vascular tone and transmits pain signals, is activated during migraine attacks.²

Furthermore, because migraines occur in a wide variety of ways, making a clinical diagnosis can be difficult. For the unwary patient, the most terrifying symptoms are frequently the visual problems. The most widely identified symptoms of migraine with aura, also referred to as classic migraine, are visual in nature. The occurrences include tunnel vision and silver stars. Although the patient may think the experience is confined to one eye, symptoms in both eyes are typical in migraine with aura because the visual symptoms originate in the striate cortex or cerebral hemispheres.¹

Meanwhile, one-sided loss of vision that is either preceded or accompanied by a headache is the distinguishing feature of ocular migraine. The longest recorded bout of OM was seven hours, after which the patient made a full recovery. More usually, the loss of vision is shorter than the migraine-associated aura, lasting typically less than five but up to thirty minutes. Additionally, OM is more common in women than men, with the onset occurring in late adolescence and adulthood.^1,4,5 

Symptoms of ocular migraine

Ocular migraineurs (people who suffer from migraines) report experiencing the following visual symptoms:

•  Scotomas (blind spots)
• Altitudinal field defects (impaired vision only above or below a horizontal line) (13%) 
• Fading (7%) 
• Blurring (19%)
• Partialloss of vision (12%) 
• complete loss of vision (50%)

Light flashes can occasionally accompany an ocular migraine. When a headache occurs together with vision loss, it usually occurs on the same side as the affected eye, and at the same time. More than 75% of patients experience repeated attacks. In contrast, seeing spots or areas of colour around the edge of the field of vision, is the visual disturbance associated with migraine with aura.^1,5

Causes and triggers

Currently, the specific cause of OM remains unknown. However, there are some factors that seem to influence it:

•  Genetics: it is shown that OM has a strong genetic component, however no clear pattern has so far been observed.^1,4
• Vasospasm: vascular constriction has been widely debated over the years as a cause for visual loss in OM, however more studies are required to confirm this as most studies lean towards the notion that migraines are not a vasospastic process.³
• Triggers: there are several factors that can affect OM, some of them include stress, high blood pressure, smoking and hormonal contraceptive pills. There are studies suggesting that OM can be induced by bending over (33%), exercise (17%), low blood sugar, dehydration and high heat.^1,4,6

Diagnosis

When diagnosing OM, it is important to approach it as a differential diagnosis; this is to rule out other causes of temporary visual loss such as papilledema, or cardiac origins where treatment and implications management vary significantly.¹ The presence of headaches and history of migraine can be supportive of OM, especially in patients that are below 40 years of age. However, its absence does not rule it out. In these cases, more testing is required, especially in patients above the age of 50, along with additional examination for atherosclerosis and cardiac disease.¹  The gradual formation of visual symptoms with full recovery suggests OM, however acute visual loss does not necessarily mean it is OM.¹

An examination during an attack is one of the most helpful diagnostic methods, nevertheless, optometric examination is also useful in migraine diagnosis, this is summarised in Table 1:

In addition to the examination, studying the history of the patient’s headache is quite important for diagnosis. This can help the health practitioner distinguish between migraines from other primary causes of headaches (such as tension-type migraines, cluster headaches, and other miscellaneous primary headaches), and secondary headaches of unknown causes.⁴

Treatment and management

Treatment and management of OM has many approaches and these are summarised in Table 2:

It is worth noting that these treatments vary from one individual to another and will require guidance from a healthcare professional. 

Impact on daily life

As migraines vary in severity, they can affect various aspects of our daily lives⁶, including:

•  Pain: as this is the most common symptom, severe headaches can be debilitating and affect people’s ability to do daily tasks.
• Sensitivity to light and sound: this can make it difficult for people to do their job or daily tasks and even socialise.
• Impact on work and productivity: severe migraines can hinder someone’s cognitive abilities and concentration, thereby affecting their ability to work and impairing their ability to be productive
•  Medical side-effects: some medications that are taken to counter migraines can cause drowsiness, tiredness, and difficulty in concentration⁷
• Emotional burden: constant pain and illness can impact a person’s mental health and as a result will lower their quality of life⁴

Prognosis

The prognosis for OM is generally good. The frequency and intensity of headaches typically decrease or it converts to migraine without headache with ageing.¹ 

Summary

Headaches have a wide range of causes and types. In order to properly address our pain, including OM, it is important to know how to differentiate primary headaches from migraines (especially OM). It might be tricky to diagnose OM, however it is quite important to address it, especially in the elderly. Table 3 contains a summary of the main points regarding OM:

In addition to this, it is important for health care professionals to educate their patients regarding OM to help improve their quality of life. 

FAQs

Is ocular migraine a mini stroke?

The short answer is no. OM and strokes are two separate conditions. Having said that, migraine is a risk factor for a stroke although this is quite rare.¹

Do ocular migraines damage your eyes?

Although rare, it has been documented in some cases, that due to the chronic nature of migraines, they can induce permanent structural changes involving the brain and the retina.²