From the Guidelines
A visual scotoma occurring without a migraine should be evaluated by an eye care professional or neurologist promptly as it may indicate a serious underlying condition. A scotoma is a blind spot or area of diminished vision in your visual field that can occur due to various causes including retinal problems, optic nerve damage, or neurological issues 1. Potential causes include retinal detachment, macular degeneration, glaucoma, multiple sclerosis, stroke, or a transient ischemic attack. Unlike migraine-associated scotomas which typically resolve within an hour and follow a pattern, isolated scotomas without headache may represent a medical emergency, particularly if sudden in onset or persistent.
Key Considerations
- The visual pathway from the retina through the optic nerve to the visual cortex can be affected at various points, and determining the exact location of the problem requires professional diagnostic testing including visual field testing, imaging studies, and possibly blood tests 1.
- Central scotomas can be detected by automated methods such as macular microperimetry, which can accurately detect both fixation and scotomas, and nonautomated methods such as the Amsler grid or observing an examiner’s face 1.
- Clinicians must be aware that some patients will maintain a sense of straight ahead related to their fovea, whereas others will re-reference their sense of straight ahead to their preferred retinal locus (PRL), suggesting that fixation is a dynamic process that is influenced by various factors.
Recommendations
- Do not delay seeking medical attention, especially if the scotoma is accompanied by other symptoms such as weakness, numbness, speech difficulties, or if it persists for more than a few minutes.
- While waiting for medical evaluation, it may help to rest your eyes and avoid activities requiring precise vision like driving.
- Prompt evaluation and diagnosis are crucial to determine the underlying cause of the scotoma and to initiate appropriate treatment to prevent further vision loss and improve quality of life.
From the Research
Definition and Causes of Visual Scotoma
A visual scotoma is an area of partial alteration in the field of vision, consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal or relatively well-preserved vision [ 2 ].
Visual Scotoma without Migraine
- Visual scotomas can occur without being associated with a migraine headache [ 2 ].
- In some cases, scintillating scotomas are considered a benign symptom when they occur without headache [ 2 ].
- However, visual field loss can also be caused by various other factors such as glaucoma, local damage to the eye, endocrine orbitopathy, toxic and nutritional neuropathy, or intracranial diseases [ 3 ].
Importance of Medical Evaluation
- It is essential to undergo a thorough medical evaluation to determine the underlying cause of a visual scotoma, as some conditions may require immediate attention [ 4, 3 ].
- Diagnostic tests such as perimetry, computed tomography, or magnetic resonance imaging may be necessary to identify the cause of the scotoma [ 3 ].
Migraine as a Contributing Factor
- Migraine can be considered a contributing factor for unexplained monocular persistent scotoma, although diseases requiring emergent intervention should always be excluded [ 4 ].
- Visual aura symptoms, including scotoma, are common in migraine patients and can be a part of the migraine aura [ 5 ].
Other Possible Causes
- Ischemic optic neuropathy is another potential cause of visual field loss, including scotoma, and can be classified into different types with distinct etiologies and clinical features [ 6 ].
- Each type of ischemic optic neuropathy requires a different management approach, highlighting the importance of accurate diagnosis [ 6 ].