What are the potential causes and recommended treatments for spotty vision lasting 20 minutes followed by a dull headache?

Migraine with Visual Aura

This presentation is classic for migraine with visual aura—the 20-minute duration of spotty vision followed by dull headache is pathognomonic for this condition, and treatment should focus on acute migraine management with NSAIDs or triptans as first-line therapy. 1

Clinical Diagnosis

Your symptoms fit the diagnostic criteria for ocular migraine (migraine with visual aura):

• Visual disturbances lasting 5-60 minutes are characteristic, with your 20-minute duration falling squarely within this range 1
• "Spotty vision" likely represents scotomas (blind spots) or scintillations (bright flickering patterns), which are the hallmark positive and negative visual phenomena of migraine aura 1
• Headache following within 60 minutes of visual symptoms confirms the diagnosis—the dull headache you describe is the typical migraine headache phase that follows the aura 1
• Complete reversibility of visual symptoms is mandatory for this diagnosis; persistent deficits would require urgent evaluation for stroke or other serious pathology 1

The gradual expansion of visual symptoms over 5-20 minutes (rather than sudden onset) helps differentiate this from vascular events like transient ischemic attacks, which occur instantaneously 1

When Neuroimaging Is NOT Needed

You do not need a brain scan if:

• This is a recurrent pattern with similar episodes 2
• Your neurologic examination is completely normal 2
• The visual symptoms resolve completely 1
• You have no "red flag" features (see below) 2, 3

The U.S. Headache Consortium guidelines explicitly state that neuroimaging is not recommended if you are not at higher risk than the general population or if results would not change management 2

Red Flags Requiring Urgent Evaluation

Seek immediate medical attention if you experience:

• Thunderclap headache (sudden, severe, "worst headache of life") 3
• Rapidly increasing frequency of headaches 2
• Headache that awakens you from sleep 2
• Focal neurologic signs (weakness, numbness, speech difficulty) that persist after the visual symptoms resolve 2
• Fever with neck stiffness 3
• Persistent visual deficits lasting beyond the typical 5-60 minute window 1
• Marked change in your usual headache pattern 2

Acute Treatment Options

First-Line Therapy

For mild to moderate attacks:

• NSAIDs are recommended as first-line treatment: ibuprofen, naproxen sodium, or aspirin 4
• Combination therapy with aspirin + acetaminophen + caffeine has strong evidence for efficacy 4
• Begin treatment as early as possible during the attack—ideally when the headache is still mild—to improve efficacy 4

For moderate to severe attacks:

• Triptans (sumatriptan, rizatriptan, naratriptan, zolmitriptan) are first-line therapy 4
• Oral triptans work well for most patients 4
• Intranasal or subcutaneous sumatriptan is particularly useful if you develop nausea or vomiting 4

Important Medication Cautions

Avoid medication-overuse headache:

• Limit acute treatment to no more than 2 days per week 4
• Using acute medications more than twice weekly can lead to rebound headaches and increasing headache frequency, potentially progressing to daily headaches 4
• This applies to all acute medications including NSAIDs, triptans, and especially opioids 4

Avoid opioids:

• Opioids should be reserved only for cases where other medications cannot be used 4
• They lead to dependency, rebound headaches, and eventual loss of efficacy 4

When to Consider Preventive Therapy

You should discuss preventive medication with your physician if:

• Headaches occur more than 2 days per week 4
• Acute treatments are not adequately controlling your symptoms 4
• Headaches significantly impair your quality of life 4

Preventive therapy reduces attack frequency and can restore responsiveness to acute treatments 4

Special Considerations

Coagulopathy screening may be warranted if:

• You experience episodes of complete binocular blindness (both eyes) with your migraines 5
• Visual symptoms are atypical or prolonged beyond 60 minutes 5
• You have risk factors for clotting disorders 5

However, this is rare—only 1.6% of migraine patients experience binocular blindness 5, and your description of "spotty vision" more likely represents the typical unilateral or bilateral scotomas of classic migraine aura 1

Medication note: If you are taking or considering topiramate for migraine prevention, be aware it can cause acute myopia and secondary angle closure glaucoma, typically within the first month of therapy, presenting with acute onset of decreased visual acuity and ocular pain 6