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In the June issue of Expert Review of Ophthalmology , a review was published covering the complete scientific knowledge concerning the clinical and pathophysiological aspects of eye movement disorders associated with vertebro-basilar stroke [1]. Ophthalmologists are indeed often confronted with patients complaining of acute diplopia. The major issue of clinical diagnosis is that diplopia, although isolated and transient, may herald a life-threatening vascular condition, such as dissecting aneurysm, or vertebro-basilar ischemic or hemorrhagic stroke. In these cases, patients will require urgent admission to neurology or neurosurgery care units. Indeed, urgent surgical or neuroradiological therapeutics might be necessary in cases of intracranial aneurysm, ischemic cerebellar stroke, hemorrhagic brainstem or cerebellar stroke, or basilar artery occlusion. Even in ischemic vertebro-basilar stroke, patients may benefit from reperfusion strategies in stroke units, deliverance of which is limited to the first 4 h after stroke [2]. On the other hand, the most frequent etiology of diplopia in older populations is ischemic ocular motor nerve palsy. In that case, beside clinical and biological evaluation, there is no need for urgent radiological procedures or hospitalization.
The practical question is: in which cases of recent diplopia is the ophthalmologist required to activate urgent neuroradiological examinations or hospitalization? The rationale for choosing the more appropriate examination tools and their optimal timing depends exclusively on the clinical evaluation [3]. We may differentiate three main ocular motor presentations of vascular event, which will require specific and different medical care from the ophthalmologist's perspective: isolated ocular motor nerve palsy, transient diplopia and central ocular motor disorders.
Isolated ocular motor nerve palsy
Vascular origin may represent at least 40% of the isolated ocular motor nerve palsies [4]. Even if nerve ischemia is the main etiology (30% for each ocular motor nerve) of isolated ocular motor nerve palsy, especially in the older population, the challenging urgent vascular diagnosis of the 10% remaining etiologies are carotid aneurysm, brainstem ischemic or hemorrhagic stroke, indirect carotid cavernous fistula, or cavernous sinus thrombosis [5-9]. Giant cell arteritis may also present with diplopia, resulting from nerve or extraocular muscle ischemia. Owing to its therapeutic consequence, diagnosis is of paramount importance and any case of isolated ocular motor palsy occurring in patients aged over 50 years should prompt emergent biological assessment (i.e., erythrocyte sedimentation...