A Closer Look at Scotoma (Blind Spot in Vision)

Experiencing unexplained blind spots or visual disturbances can be alarming, especially when they come out of the blue. One possible cause is scotoma.

Scotomas are visual disruptions that can appear as blurry, dark, or shimmering areas in your central or peripheral vision. Understanding what scotoma is, what causes it, and when to see a doctor can help protect your vision and ease your anxiety.

What is a Scotoma?

A scotoma is a temporary or permanent blind spot in your field of vision. Everyone has a pinhead-sized blind spot that occurs where the optic nerve enters the retina. 

Most people don't notice these blind spots because our brains fill in the missing information. However, a scotoma is an abnormal blind spot. 

This visual field defect might indicate an underlying health condition. There are different kinds of scotomas, and each affects your field of vision differently.

What Are the Different Types of Scotomas?

Various types of scotomas create different blind spots in your eye. The kind of scotoma determines how your sight is affected.

Some types of scotomas include:

Type	Description	Symptoms
Scintillating scotomas	Unlike the other types, a scintillating scotoma doesn’t look like a dark spot.	Flickering lights, alternating waves of light or dark, and an arc-shaped or jagged line.
Central scotomas	A central scotoma is a blind spot directly in your line of sight. This type causes visual field defects that make daily tasks challenging or impossible.	Difficulties with reading, driving, and seeing colors. People with central scotomas may look from the side of their eyes to see.
Paracentral scotomas	A paracentral or arcuate scotoma causes vision loss within 10 degrees of the focal point. This blind spot won’t be directly in the line of sight.	This scotoma often begins as a single area of relative loss that gets larger. It's typically caused by glaucoma.
Hemianopic scotomas	Affects half of the visual field. Typically caused by a cerebrovascular injury or tumor.	Causes severe reading problems.
Junctional scotomas	A junctional scotoma occurs when the place where the optic nerve and optic chiasm meet is damaged. The optic chiasm is the part of the brain where the optic nerves partially cross.	It typically presents as a central scotoma in one eye and temporal field loss in the other. The vision loss depends on which part of the optic nerve is damaged.

What are the Symptoms of a Scotoma?

Scotomas can affect the center, near-center, or periphery of your vision. They can also appear as positive or negative scotomas.

A positive scotoma appears as a visible spot or flickering light, while a negative scotoma is an invisible gap in vision that you might only notice by missing objects.

Other symptoms include:

• A dark, blurry, or fuzzy spot
• Floaters or dots
• Arcs of light
• A spot that flickers between light and dark
• Possible headache 
• Trouble reading or seeing specific colors or details

If you notice a blind spot, call your eye doctor and schedule an appointment immediately.

What Causes a Scotoma?

Many conditions and factors can cause a scotoma to develop, including:

• Migraines. A temporary scintillating scotoma might appear during a migraine. 
• Glaucoma. An eye disease that can damage the optic nerve due to fluid buildup in the front part of the eye. It can cause vision disturbances, including scotoma.
• Certain medications. Some drugs can cause vision changes because of direct toxicity to photoreceptors. In some cases, stopping the offending medication may halt progression and reverse the scotoma, but recovery is not guaranteed.
• Sclerotherapy. Sclerotherapy is a medical procedure that treats varicose and spider veins. This can cause a scotoma. 
• Macular degeneration. Age-related macular degeneration (AMD) can cause blurred vision and scotomas as the macula deteriorates.
• Diabetic retinopathy. Diabetic retinopathy occurs when high blood sugar levels damage the back of the eye (retina). Without treatment, diabetic retinopathy can cause low vision, a central scotoma, or even blindness. 
• Optic neuropathy. Optic neuropathy happens when blood flow to the optic nerve decreases or is interrupted, leading to sudden scotoma or vision loss.
• Toxic optic neuropathy. Occurs when a toxin, like alcohol or drugs, damages the optic nerve. Both toxic optic neuropathy and optic neuropathy can cause central or cecocentral scotoma. 
• Optic atrophy. Optic atrophy is the death of retinal ganglion cells that comprise the optic nerve. This condition can lead to poorer visual acuity and color vision.

Can Scotomas be a Sign of Something Serious?

Various conditions can lead to scotoma. For instance, a brain injury like an occipital cortex lesion can rarely cause scotomas.

Scotomas can also be a sign of an underlying health condition that requires treatment. These include:

• MS
• Stroke
• Seizures
• Hypertension
• Preeclampsia (high blood pressure during pregnancy)

When Should You See a Doctor?

You should see your doctor if you suddenly experience a blind spot or other visual disturbances. Seek emergency medical care if any of the following signs or symptoms accompany the scotoma:

• Confusion or disorientation
• Dizziness or nausea
• Muscle weakness
• Sudden intense headache
• Numbness in your limbs or face
• Slurred speech or difficulty speaking

A scotoma that follows a head or eye injury also warrants emergency medical care.

How are Scotomas Treated?

Treatment approaches depend significantly on the cause and severity of your scotoma, ranging from medical interventions to rehabilitation strategies.

Medical Treatments

• Anti-VEGF injections. Effective for wet AMD or diabetic macular edema, reducing abnormal blood vessel growth and fluid leakage, stabilizing or even improving vision.
• Laser therapy. Treats proliferative diabetic retinopathy, sealing off leaking vessels and lowering the risk of further vision loss.
• Steroid treatments. Critical for conditions like optic neuritis or giant cell arteritis, helping to reduce inflammation and prevent irreversible damage.
• Surgery. Necessary for retinal detachment or severe glaucoma to restore or preserve vision.

Rehabilitation and Support

If your vision loss is permanent, you can get aid from various tools, therapy, or community support:

• Magnifying aids. Enlarged print devices or electronic magnifiers for central vision loss.
• Prism glasses. Expand visual fields for patients with peripheral vision loss or hemianopia.
• Vision therapy. Helps retrain eye movements and scanning techniques, improving daily functioning.
• Community Support. Groups and resources from organizations like the Macular Degeneration Association or the Glaucoma Research Foundation provide emotional support and practical coping strategies.