Scotoma (Blind Spot in Vision): Types, Causes & Treatment

Scotoma is a blind spot that partially obstructs vision. It is localized and does not impact other areas of the visual field. 

This condition results in the appearance of a blurry or dark spot within the visual field or a blinking light within a single spot in the eye. 

Types of Scotoma

There are three types of scotoma.

1. Paracentral scotomas: A paracentral scotoma is isolated vision loss within 10 degrees of fixation. This does not occur in the central field of vision. 
2. Central scotomas: A central scotoma is a blind sport that occurs directly in the center of the visual field. This type of scotoma can appear as a dark spot, blurred vision, or a smudge in the center of the eye. 
3. Scintillating scotomas: A scintillating scotoma is a visual blind spot that fluctuates between light and dark.

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Causes of Scotoma

Causes of scotoma include the following:

• Eye injury
• Retinitis pigmentosa
• Glaucoma
• Trauma to the head
• An allergic reaction
• Stroke
• Diabetic retinopathy
• Hypertension and hypotension
• Sclerotherapy
• Macular degeneration

Is Scotoma Serious?

Scotomas are typically not serious and usually go away without the need for treatment or medical intervention. However, they can be an indication of an underlying health issue, and some health issues that cause blind spots can be serious. 

A temporary blind spot may be the result of a migraine headache, but it could also be an indication of a condition that can affect eyesight, such as diabetes. Therefore, it is important to seek medical attention as soon as possible if you experience a blind spot that does not go away on its own. 

Symptoms of Scotoma

There are no other symptoms of a scotoma beyond the isolated blind spot. This condition does not affect other parts of the eye. 

Again, however, a scotoma may be an indication of an underlying health issue. As mentioned, some of the most common include retinitis pigmentosa, hypertension, glaucoma, migraine, diabetes, and allergies. There may be symptoms that accompany the underlying cause. For example, it is common to have a temporary blind spot when experiencing a migraine headache.

Risk Factors

Several factors can place certain individuals at greater risk of experiencing a scotoma than others. 

A genetic history of retinitis pigmentosa, glaucoma, diabetes, and obesity are risk factors for scotomas. Other risk factors for general scotomas include the following:

• Hypotension
• Migraine
• Raynaud’s phenomenon (changing of the color of the skin in response to stress or cold) 
• Snoring
• Frequency of disc hemorrhage

In one study, researchers found that no lifestyle factors, such as smoking, significantly increased the risk of experiencing a scotoma. 

Diagnosis

A scotoma can only be diagnosed by a medical professional. It is generally optimal to see both a general practitioner and a vision specialist to determine the underlying cause. A diagnosis is typically made using both a dilated eye exam and an automated visual field test. 

• A dilated eye exam is an intentional dilation of the eyes to allow for a full assessment of the retina and optic nerve. 
• An automated visual field test is a measurement of how far the eye can see in different directions as well as the sensitivity of the eye in various aspects of the visual field. This test can allow for the detection of disease and injury. 

Treatment for Scotoma

In most cases, scotomas disappear without the need for treatment. 

Temporary Solutions

Blind spots that occur in parts of the visual field often do not last more than one hour. You can potentially alleviate symptoms by lying down, consuming fluids, and taking a pain reliever, such as ibuprofen.

Longer-Term Solutions & Diagnosed Cases

For diagnosed cases, treatments may involve beta-blockers to relax blood vessels, antidepressants to manage neurotransmitter levels and reduce the risk of migraines, and anti-epileptic drugs that can help to manage neurological causes of scotomas.

Additionally, symptoms may be treated simultaneously if there is a related condition responsible, such retinitis pigmentosa. This means that symptoms of scotoma, as well as the underlying condition, would be treated at the same time.

When to See a Doctor

It is necessary to see a doctor if you have a blind spot lasting longer than one hour, as this may be an indication of an underlying health issue.

Scotoma FAQS

What should I do if I have a partial loss of vision?

You should seek emergency medical attention if you experience any sudden loss of vision, even if it’s a small spot in your visual field. Always see a doctor promptly if your vision is not restored within one hour.

How can I get a scotoma?

Scotomas are caused by infections, injuries, or underlying health conditions, such as diabetes.

How long does scotoma last?

In most cases, scotomas are temporary, lasting only 20 to 30 minutes. See a doctor if your scotoma lasts longer than an hour.

References

1. Better Simulation of Vision with Central and Paracentral Scotomas. (June 2020). Investigative Ophthalmology & Visual Science.

2. A Case of Paracentral Acute Middle Maculopathy Presenting Scotoma and Normal Visual Acuity. (December 2021). Korean Journal of Ophthalmology.

3. Visual Fields. (1990). Clinical Methods: The History, Physical, and Laboratory Examinations.

4. Functional and Cortical Adaptations to Central Vision Loss. (October 2005). Visual Neuroscience.

5. Neuro-Ophthalmology of Brain Tumors. (2012). Brain Tumors.

6. Ocular Syphilis: Clinical Manifestations and Treatment Course. (December 2019). Wisconsin Medical Journal.