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On the basis of the history, examination, and investigations, retinal migraine was diagnosed according to the International Classification of Headache Disorders, third edition (1.2 migraine with aura; 1.2.4 retinal migraine). This classification system describes retinal migraine as a subtype of migraine with aura.
Retinal migraine (also called ophthalmic or ocular migraine) is relatively rare but is sometimes a cause of transient monocular blindness in young adults. It manifests as recurrent attacks of unilateral visual disturbance (positive symptoms) or blindness (negative symptoms) lasting from minutes to 1 hour, associated with minimal or no headache.
Some patients describe a positive visual symptom/disturbance in a mosaic pattern of scotomata that gradually enlarge, producing total or near-total unilateral visual loss. Precipitating factors may include emotional stress, hypertension, and hormonal contraceptive pills, as well as exercise, high altitude, dehydration, smoking, hypoglycemia, and hyperthermia.
Retinal migraine is believed to result from transient vasospasm of the choroidal or retinal arteries. A history of recurrent attacks of transient monocular visual disturbance or blindness, with or without a headache and without other neurologic symptoms, can suggest retinal migraine. A personal or family history of migraine can confirm the diagnosis.
Ruling out eye disease or vascular causes, especially when risk factors for arteriosclerosis exist, is important; that is, the condition must be differentiated from ocular or vascular causes of transient monocular blindness, mainly carotid artery disease.
Carotid duplex ultrasonography, transcranial Doppler ultrasonography, magnetic resonance angiography, or CT angiography of the brain may be helpful. Fluorescein or cerebral angiography is rarely necessary. A hypercoagulability workup and evaluation of the erythrocyte sedimentation rate may be useful in excluding other coagulation disorders associated with retinal vasculopathy.
Regarding management, calcium-channel blockers have shown some efficacy. Even in patients with low blood pressure, nifedipine 10-20 mg/d is generally tolerated. From the available literature on treatment of this condition, it is recommended that triptans, ergots, and beta-blockers be used with caution or avoided in patients with retinal migraine owing to the potential for exacerbating vasoconstriction of the retinal artery. Transient vision loss in retinal migraine has been associated with future onset of permanent vision loss from occlusive conditions such as central retinal artery occlusion and branch retinal artery occlusion.
Jasmin Harpe, MD, MPH, Headache Fellow, Department of Neurology, Harvard University, John R. Graham Headache Center, Mass General Brigham, Boston, MA
Jasmin Harpe, MD, MPH, has disclosed no relevant financial relationships.
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