Cicadic Intrusions

STEVEN L. LEWIS, MD, FAAN Neuro-ophthalmology p. 1192-1193 October 2019, Vol.25, No.5 doi: 10.1212/


This issue of Continuum was created to inform us about the recognition, diagnosis, and management of the conditions that can present to the neurologist as disorders of vision, eye movement, or pupillary function. As it is a noncore topic in the Continuum curriculum, it has been 5 years since the last issue on neuro-ophthalmology (unlike the usual 3-year cycle for core topics in Continuum). We are privileged that Dr Marc Dinkin accepted my request to take on the challenge of this important theme, and I extend my sincere thanks to him for bringing on such expert neuro-ophthalmologists and educators as contributors to this issue.

We are privileged that Dr Marc Dinkin accepted my request to take on the challenge of this important theme, and I extend my sincere thanks to him for bringing on such expert neuro-ophthalmologists and educators as contributors to this issue.

The issue begins with the article by Dr Marc A. Bouffard, who reminds us of the important neuroanatomic and physiologic concepts underlying pupillary size and responses to light and near as well as the disorders that affect those functions. Dr Mark J. Morrow then reviews the many causes of ischemic optic neuropathy, with particular emphasis on those conditions for which it is critical that neurologists maintain a high index of suspicion (eg, arteritic anterior ischemic optic neuropathy related to giant cell arteritis). Dr Jeffrey L. Bennett then discusses the diagnosis and management of the many causes of inflammation of the optic nerve (optic neuritis), including, but not limited to, idiopathic optic neuritis and optic neuritis associated with multiple sclerosis, neuromyelitis optica (NMO) spectrum disorders, and myelin oligodendrocyte glycoprotein (MOG) antibody–associated disease. Dr Cristiano Oliveira next reviews both toxic-metabolic and hereditary optic neuropathies, causes of optic nerve dysfunction that share many pathophysiologic underpinnings.

Dr Matthew J. Thurtell covers the current diagnosis and management of idiopathic intracranial hypertension, a disorder that commonly presents to neurologists and represents an important cause of preventable visual loss. Next, Dr Heather E. Moss walks us through the visual pathway from the optic chiasm through the postchiasmal regions to review the characteristic signs and symptoms and management of the disorders that can cause visual dysfunction in these regions.

Drs Sashank Prasad and Marc Dinkin then present an overview of the many higher cortical vision disorders, while also providing details about their initial discovery that place these disorders into their historical context to further inform our current understanding of these fascinating, but also often quite disabling, presentations.

The issue then includes two articles that discuss disorders affecting the movements of the eyes. Regarding this—and please excuse this brief intrusion for clarification—readers will note that neuro-ophthalmologists uniquely use a specific term, the efferent visual system, to refer to the pathways and mechanisms that control eye movement. Although evoking the implausible scenario of images being projected on the outside world through the pupils, this term is used in this issue, as in common neuro-ophthalmologic parlance, to refer to the overall set of pathways and mechanisms involved in eye movements and their control. In fact, as this editorial is being written, I am keenly reminded of the need for outstanding afferent and efferent visual pathway function to avoid stepping on the cicadalike spotted lanternfly that has invaded parts of Pennsylvania.

The first of the articles relating to disorders of eye movement is written by Dr Christopher C. Glisson, who provides his approach to and management of (binocular) diplopia, a symptom that occurs due to misalignment of the eyes and often has a neurologic cause. Next, Dr Janet C. Rucker demystifies the topic of nystagmus and saccadic intrusions and the disorders that cause these abnormalities that affect eye movements.

In the subsequent article, Drs Lynn Gordon and Marc Dinkin review the clinical features, diagnosis, and management of the paraneoplastic syndromes that may present with neuro-ophthalmologic features. Dr Eric R. Eggenberger then describes the clinical features and management of the most common infectious causes of optic neuropathies.

In the final review article of the issue, Drs Fiona Costello and James N. Scott provide a well-illustrated and encyclopedic review of the imaging features of neuro-ophthalmologic disorders.

After reading the issue and taking the Postreading Self-Assessment and CME Test written by Drs Douglas J. Gelb and James W. M. Owens Jr, you may earn up to 20 AMA PRA Category 1 CreditsTM toward self-assessment and CME or, for Canadian participants, a maximum of 20 hours toward the Self-Assessment Program (Section 3) of the Maintenance of Certification Program of the Royal College of Physicians and Surgeons of Canada. Additional credit can be obtained by listening to Continuum Audio interviews associated with this and other Continuum issues, available to all subscribers, and completing tests on the Continuum Audio web platform or mobile app. Continuum Audio is also accredited by the Royal College of Physicians and Surgeons of Canada.

I would like to give my sincere appreciation to Dr Dinkin for his expert and devoted guest editorship of this remarkable issue. I would also like to thank him for his meticulous and timely attention to all the details and decisions that arise in such a complex issue and for enlisting such expert subspecialist authors to assist us in the diagnosis and management of the many patients who present to us with neuro-ophthalmologic clues to their underlying disorders.


© 2019 American Academy of Neurology.