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Idiopathic intracranial hypertension is a syndrome of increased intracranial pressure of unclear etiology that most often occurs in obese women of childbearing age but can also occur in men, children, and older adults. This article reviews the diagnostic criteria, clinical features, neuroimaging findings, differential diagnosis, and management options for this condition.Recent population studies have found that the annual incidence of idiopathic intracranial hypertension is increasing in association with obesity rates, whereas recent scientific studies indicate a possible role for androgen sex hormones and adipose tissue in the pathogenesis of the disease. Prospective clinical trials have demonstrated a role for weight loss, acetazolamide, and topiramate in the management of mild disease. A recently begun randomized multicenter trial of surgical interventions will provide insight into the indications for surgical intervention, optimal timing and choice of intervention, and long-term outcomes.Idiopathic intracranial hypertension is a disorder producing symptoms and signs of increased intracranial pressure in the absence of an alternative cause. The main goals of treatment are to preserve visual function and alleviate symptoms, which can usually be achieved with a combination of weight loss, medical therapies, and surgical interventions depending on the severity of symptoms and vision loss, response to treatment, and subsequent clinical course.

Patients with syphilis can present with optic disc oedema (ODE) without visual compromise, which has been primarily attributed to papilloedema from raised intracranial pressure or optic perineuritis from optic nerve sheath inflammation. We report four cases of ODE in the setting of syphilis with preserved visual function, normal intracranial pressure, and no enhancement of the optic nerve or sheath on magnetic resonance imaging. We propose the term “incipient syphilitic papillitis” for cases presenting with ODE, preserved vision and absence of optic nerve sheath enhancement, which is likely a more common presentation than syphilitic optic perineuritis.

Purpose: To describe a novel transcutaneous infraorbital nerve biopsy technique which can be performed to aid in the diagnosis of perineural invasion (PNI) of facial cutaneous squamous cell carcinoma (SCC).Methods: A single-center retrospective chart review was performed. Patients diagnosed with SCC with PNI via an infraorbital nerve biopsy between February 2019 and February 2020 were included. Data collected consisted of patient demographics, medical history, clinical presentation and exam, histologic and radiographic findings, treatment, and outcomes.Results: Four patients (3 male, 1 female) met inclusion criteria. The mean age at diagnosis was 79.5 years (range 66-85 years). Three of the four patients had a history of facial skin lesions, including actinic keratosis and SCC, involving the nose, cheek, or ear. One patient had no history of cutaneous malignancy. All patients presented with cranial neuropathies, including total V2 hypoesthesia. The most common presenting symptom was facial pain, followed by diplopia, unilateral facial weakness, and hypoesthesia in the V1 and/or V2 distribution. Transcutaneous infraorbital nerve biopsy in all patients revealed squamous cell carcinoma with no biopsy complications.Conclusion: Definitive diagnosis of PNI can be challenging but is important to minimize tumor-related morbidity. Infraorbital nerve biopsy can establish this diagnosis, especially in the context of negative or indeterminate imaging findings. This work comprises the first description of a transcutaneous approach to infraorbital nerve biopsy, which is a minimally invasive technique that can be performed in an outpatient procedure suite with limited to no sedation.

Syndrome of oculopalatal tremor (OPT) causes pendular nystagmus of the eyes and its disabling consequence on the visual system. Classic pharmacotherapeutic studies revealed reduction in the eye velocity of the oscillatory waveforms. Subjective improvement in vision, however, remains out of proportionately low. Elegant models depicting quasi-sinusoidal coarse oscillations of the eyes highlighted two distinct oscillators; one at the inferior olive causing primary 2 Hz oscillations, while the second, independent oscillator, at the cerebellum adding the randomness to the waveform. Here we examined whether pharmacotherapy affects the randomness of the oscillatory waveform. Horizontal, vertical, and torsional angular eye positions were measured independently from both eyes as six subjects with OPT directed gaze toward a straight-ahead target. The measurements were performed before administration of alpha-2-delta calcium channel blocker (gabapentin) or NMDA receptor antagonist (memantine) and after the subjects were treated with each of these drugs for at least 8 days. Amplitude and velocity of eye oscillations were reduced by gabapentin and memantine, but there was an increase in the waveform randomness. We found that the increase in randomness was proportionate to the amount of reduction in the waveform velocity or amplitude. Hierarchical clustering revealed distinct patterns of oscillatory waveforms, with each subject belonging to a specific cluster group. The pharmacotherapy changed the waveform clustering pattern of the waveform in each subject. We conclude that in addition to incomplete resolution of the oscillation intensity, increased randomness could be one of the reasons why there is not enough clinical difference in the patients' visual quality.

Purpose: To report a case of autoimmune retinopathy and optic neuropathy associated with an enolase-positive renal oncocytoma. Observations: A 41-year-old man presented with subacute, painless, bilateral vision loss. On initial examination, visual acuity measured 20/125 OD and 20/1250 OS, and telangiectatic vessels were noted on the optic nerves and in the maculae. Goldmann perimetry showed bilateral, cecocentral scotomas, and electroretinography demonstrated reduced photopic and scotopic signals, concerning for autoimmune retinopathy. Serum testing showed multiple positive anti-optic nerve and anti-retinal antibodies, including to alpha-enolase. Extensive systemic workup was negative except for a large, exophytic, right renal mass. Biopsy was consistent with a benign oncocytoma, and immunohistochemical staining showed diffusely positive alpha-enolase staining. The patient was treated with a five-day course of intravenous methylprednisolone and plasmapheresis with minimal improvement. Surgical excision of the oncocytoma was performed. At 9-months post-operatively, visual acuity had improved to 20/40 OU, with corresponding improvement on visual field and electroretinography testing. Conclusions and importance: To our knowledge, this is the first report of autoimmune retinopathy and optic neuropathy associated with a renal oncocytoma. The case highlights the importance of a thorough systemic workup in cases of suspected autoimmune retinopathy and reminds clinicians that even tumors considered benign can have distal effects on other organs. Keywords: Autoimmune retinopathy, Optic neuropathy, Oncocytoma

To determine whether the beneficial effects of acetazolamide (ACZ) in improving vision at 6 months continues to month 12 in participants of the Idiopathic Intracranial Hypertension Treatment Trial (IIHTT).Nonrandomized clinical study.In the IIHTT, subjects were randomly assigned to placebo-plus-diet or maximally tolerated dosage of acetazolamide-plus-diet. At 6 months subjects transitioned from study drug to ACZ. This resulted in the following groups: (1) ACZ to ACZ; n = 34; (2) placebo to ACZ; n = 35; (3) ACZ to no treatment; n = 16; and (4) placebo to no treatment; n = 11. Ninety-six IIHTT subjects had evaluations at 6 and 12 months. Our main outcome measure was change from month 6 to month 12 in visual field mean deviation (MD) with secondary measures being change in papilledema grade, ETDRS scores, and quality-of-life (QoL) measures.The ACZ to ACZ group improved 0.35 dB, P = .05; placebo subjects with no ACZ improved 0.81 dB MD, P = .07 at 12 months. The other groups improved 0.35-0.46 dB MD. Mean improvements in papilledema grade occurred most markedly in the group that exchanged placebo for ACZ (0.91 units, P .001). QoL and headache disability scores showed significant improvements in the placebo group with added ACZ.Improvements in MD continued from month 6 to month 12 of the IIHTT in all treatment groups, most marked in the placebo group tapered off study drug. Adding ACZ to the placebo group significantly improved papilledema grade, headache, and QoL measures.

Purpose: To characterize visual loss across the full visual field in idiopathic intracranial hypertension (IIH) patients with mild central visual loss. Methods: We tested the full visual field (50° nasal, 80° temporal, 30° superior, 45° inferior) of 1 eye of 39 IIH patients by using static perimetry (size V) with the Open Perimetry Interface. Participants met the Dandy criteria for IIH and had at least Frisen grade 1 papilledema with better than -5 dB mean deviation (MD) centrally. Two observers (MW and AS) evaluated the visual field defects, adjudicated any differences, and reviewed optical coherence tomography data. Results: We found a greater MD loss peripherally than centrally (central 26°). The median MD (and corresponding median absolute deviations) was -1.37 dB (1.61 dB) for the periphery and -0.77 dB (0.87 dB) for the central 26°, P < 0.001. There were about 30% more abnormal test locations identified in the periphery (P = 0.12), and the mean defect depth increased with eccentricity (P < 0.001). The most frequent defect found was a temporal wedge (23% of cases) in the periphery with another 23% that included this sector with inferior temporal loss. Although the presence of papilledema limited correlation, 55% of the temporal wedge defects had optical coherence tomography retinal nerve fiber layer deficits in the corresponding superonasal location. Other common visual field defects were inferonasal loss, superonasal loss, and superior and inferior arcuate defects. Seven patients (18%) had visual field defects in the periphery with normal central visual field testing. Conclusion: In IIH patients, we found substantial visual loss both outside 30° of the visual field and inside 30° with the depth of the defect increasing linearly with eccentricity. Temporal wedge defects were the most common visual field defect in the periphery. Static threshold perimetry of the full visual field appears to be clinically useful in IIH patients.

Upper-eyelid ptosis is frequently encountered in clinical practice but has a broad differential diagnosis. It can produce visual symptoms when the pupil is encroached by the upper eyelid. In this chapter, we begin by reviewing the clinical features that help with localization of the lesion responsible for upper-eyelid ptosis. We next describe the components of the eyelid examination that help to quantify and characterize upper-eyelid ptosis. We then discuss the features of levator dehiscence and list its common causes, which include involutional changes in orbital connective tissues, long-term use of contact lenses, and iatrogenic trauma. Lastly, we review the treatment options for levator dehiscence.

Lesions in the orbital apex, superior orbital fissure, and cavernous sinus can give rise to characteristic combinations of cranial nerve palsies. In this chapter, we begin by reviewing the clinical features and common causes of syndromes of the orbital apex, superior orbital fissure, and cavernous sinus. We go on to discuss the pathogenesis and clinical features of rhino-orbital mucormycosis in detail, because it has a grave prognosis if it is not diagnosed and treated in a timely fashion. We then describe the roles and importance of imaging and tissue biopsy for its diagnosis. Lastly, we review the management of rhino-orbital mucormycosis, which includes rapid reversal of predisposing factors (such as diabetic ketoacidosis), immediate initiation of empiric antifungal treatment, and early surgical debridement of infected tissue.

Intermittent diplopia is a common complaint that has a broad differential diagnosis. In this chapter, we begin by discussing the crucial role of the history in the evaluation of intermittent diplopia. We next review the differential diagnosis for intermittent diplopia, which includes conditions involving the eye, extraocular muscle, neuromuscular junction, cranial nerve, brainstem, and cerebellum. We emphasize the importance of distinguishing monocular diplopia from binocular diplopia when determining the appropriate diagnostic approach. We then review the symptoms, signs, pathogenesis, and diagnostic evaluation of superior oblique myokymia. We discuss practical strategies for detecting the ocular oscillations of superior oblique myokymia. Lastly, we review the medical and surgical management options for superior oblique myokymia.

Upbeat nystagmus is a less common type of central vestibular nystagmus that is often transient. It is a vertical jerk-waveform nystagmus with downward slow phases and upward quick phases. In this chapter, we begin by reviewing the clinical features of upbeat nystagmus. Since it can be produced by lesions in a variety locations in the brainstem and cerebellum, we next describe the symptoms and signs that can help to localize the causative lesion. We list the causes of upbeat nystagmus. We then discuss the clinical and imaging findings in Wernicke encephalopathy, which is a common cause of upbeat nystagmus, and we review the management of Wernicke encephalopathy. Lastly, we briefly discuss the medical treatment options for persistent upbeat nystagmus.

Arteritic ischemic optic neuropathy occurs in the setting of giant cell arteritis and often produces devastating irreversible vision loss. It is a medical emergency because there is a high risk of fellow eye involvement if high-dose corticosteroid treatment is not initiated in a timely fashion. In this chapter, we begin by reviewing the clinical features of anterior and posterior ischemic optic neuropathy. We next review the clinical features of arteritic ischemic optic neuropathy. We then discuss the clinical features and workup for giant cell arteritis. Lastly, we review the initial and long-term management approach for ischemic optic neuropathy occuring in the setting of giant cell arteritis.

A disorder of higher visual function should be considered when visual complaints are out of proportion to examination findings. Such disorders can remain undiagnosed until other cognitive deficits develop. In this chapter, we begin by reviewing the various disorders of higher visual function, which include visual agnosias, simultanagnosia, ocular motor apraxia, and optic ataxia. We next discuss practical strategies to detect these disorders. We then discuss common causes of these disorders and their diagnostic evaluation. We focus our discussion on the clinical features and imaging findings in the visual variant of Alzheimer disease, where the parieto-occipital lobes are preferentially affected in the early stages of the disease.

Gaze-evoked nystagmus is the one of the most common types of nystagmus encountered in clinical practice, but it is poorly localizing. It is often confused with physiologic “end-point” nystagmus. In this chapter, we begin by discussing the pathogenesis of gaze-evoked nystagmus. We next describe its clinical features as well as features that help distinguish it from “end-point” nystagmus, which is physiologic and of no concern. We then review common causes of gaze-evoked nystagmus, which include drugs (especially anticonvulsants), cerebellar degenerations, multiple sclerosis, and episodic ataxias. Lastly, we discuss the diagnostic approach to the patient with gaze-evoked nystagmus and basic management strategies.

Visual hallucinations are perceptions that occur in the absence of a corresponding external visual stimulus, whereas visual illusions are misinterpretations of an external visual stimulus. Migraine visual aura is a common cause of transient visual hallucinations. Similar symptoms can occur in patients who have occipital lesions or as a manifestation of occipital seizures. In this chapter, we begin by reviewing the common causes of visual hallucinations and illusions. We next review the clinical features of migraine visual aura and discuss the approach to the patient who has aura without a subsequent migraine headache. We then review features that help to distinguish aura from retinal migraine and occipital seizures. Lastly, we discuss the management approach for migraine with aura.

Formerly known as congenital nystagmus, infantile nystagmus can occur in isolation or in association with other ophthalmic, neurologic, and endocrine abnormalities. It is predominantly horizontal and conjugate in most patients. It can have a sinusoidal (pendular) or jerk waveform with accelerating slow phases. While it does not usually cause oscillopsia, it can cause blurred vision. In this chapter, we begin by reviewing the clinical features of infantile nystagmus. We next discuss the diagnostic approach to identify conditions that can be associated with infantile nystagmus. We then present a contemporary approach to the management of infantile nystagmus, which includes optical, medical, and surgical strategies.

When visual complaints are out of proportion to examination findings, nonorganic vision loss or a disorder of higher visual function may be suspected. However, certain ophthalmic causes of vision loss should also be considered. In this chapter, we begin by reviewing potential causes of unexplained vision loss, including refractive error, corneal disorders (e.g., keratoconus), optic neuropathy, and occult retinopathy. We next discuss clinical strategies and investigations that can help to identify certain causes of unexplained vision loss. Lastly, we discuss the clinical features, causes, and diagnostic evaluation of occult retinopathy, with a focus on conditions that cause cone photoreceptor dysfunction, such as cone dystrophy, cancer-associated retinopathy, and autoimmune retinopathy.

A diagnostic dilemma often arises when a patient with headaches is found to have optic nerve head elevation. In this chapter, we begin by reviewing the potential causes of optic nerve head elevation, which include papilledema, optic disc edema from another cause, optic nerve head infiltration, and anomalous optic nerve head elevation that mimics optic disc edema (pseudopapilledema). We next list the common causes of pseudopapilledema and discuss strategies that help to distinguish pseudopapilledema from papilledema. We then review the clinical features and diagnostic evaluation of optic nerve head drusen, a common cause of pseudopapilledema, and describe ophthalmic imaging techniques that can help to distinguish optic nerve head drusen from papilledema.

Saccadic dysmetria, intrusions, and oscillations are often encountered in association with certain cerebellar and neurodegenerative diseases. When severe, they can give rise to visual symptoms, such as difficulty with reading and oscillopsia. In this chapter, we begin by reviewing the clinical features of saccadic dysmetria, in which the saccadic amplitude is inappropriately calibrated. We next review the clinical features of saccadic intrusions and oscillations, which include square-wave jerks, macrosaccadic oscillations, ocular flutter, and opsoclonus. We review the common causes of these entities and discuss the diagnostic workup. Lastly, we discuss potential medical treatments to reduce the magnitude and frequency of saccadic intrusions and oscillations.

Supranuclear ophthalmoplegia results from an interruption of the saccadic, pursuit, optokinetic, or vergence inputs to the ocular motor nuclei. In this chapter, we begin by reviewing potential causes for difficulty reading. We next review the neuro-ophthalmic and neurologic features of progressive supranuclear palsy, which can include a vertical supranuclear ophthalmoplegia, convergence insufficiency, square-wave jerks, upper-eyelid retraction, reduced blink rate, apraxia of eyelid opening, and blepharospasm. We then discuss the differential diagnosis of progressive supranuclear palsy and point out clinical features that help to differentiate these conditions. Lastly, we present a practical approach to the management of the visual symptoms commonly caused by progressive supranuclear palsy.

There is a broad differential diagnosis for bilateral optic neuropathies, including inflammatory, ischemic, compressive, traumatic, nutritional, toxic, and inherited causes. In this chapter, we begin by discussing the approach to the patient who has bilateral symmetric optic neuropathies. We next review the genetic basis, clinical features, and natural history of autosomal dominant optic atrophy. We list other deficits that can occur in up to 20% of patients with this condition, which can include sensorineural hearing loss, ataxia, myopathy, peripheral neuropathy, spastic paraparesis, and chronic progressive external ophthalmoplegia. Lastly, we discuss the evaluation and management approach for autosomal dominant optic atrophy.

Thyroid eye disease is the most common cause of orbital disease encountered in clinical practice. It most often occurs in patients with Graves disease, but can also occur in the absence of thyroid dysfunction. In this chapter, we begin by reviewing the clinical features and natural history of thyroid eye disease. We next discuss the diagnostic evaluation of thyroid eye disease, including the roles of imaging and visual field testing. We then briefly review the differential diagnosis, which includes idiopathic orbital inflammation, orbital cellulitis, and carotid-cavernous fistula. Lastly, we discuss the management approach for thyroid eye disease. Many patients have only mild disease and can be managed with supportive treatments, such as artificial tears, prisms, and selenium supplementation. However, patients with moderate to severe thyroid eye disease often require more aggressive treatments, such as immunosuppression with systemic corticosteroids, orbital irradiation, and orbital decompression surgery.

Part of the “What Do I Do Now?” series, Neuro-Ophthalmology uses a case-based approach to cover common and important topics in the examination, investigation, and management of afferent (visual), efferent (eye movement), eyelid, pupil, and orbital disorders. Each chapter provides a discussion of the diagnosis, key points to remember, and selected references for further reading. For this new edition, all cases and references have been updated and several new cases have been added. Neuro-Ophthalmology is an engaging collection of thought-provoking cases that clinicians can use when they encounter difficult patients. The volume is also a self-assessment tool that tests the reader’s ability to answer the question, “What do I do now?”

Blepharospasm is an involuntary closure of the eyes that is caused by spasm of the orbicularis oculi. It can be isolated or associated with certain ophthalmic and neurologic disorders, such as progressive supranuclear palsy. In this chapter, we begin by reviewing the clinical features of benign essential blepharospasm and oromandibular dystonia (Meige syndrome). We next review the clinical features of apraxia of eyelid opening and hemifacial spasm, since these disorders can occasionally be confused with benign essential blepharospasm. Lastly, we discuss management options for benign essential blepharospasm, which include injections of botulinum toxin A into the orbicularis oculi and surrounding muscles.

Horner syndrome can be caused by a lesion anywhere along the oculosympathetic pathway. Although there may be other signs that help with localization of the lesion, the syndrome often occurs in isolation. In this chapter, we begin by reviewing the anatomy of the oculosympathetic pathway. We next describe the clinical features of Horner syndrome, which include ipsilateral miosis and eyelid ptosis. We then discuss the role and potential pitfalls of pharmacologic pupil testing in the diagnostic evaluation of Horner syndrome. We review the potential causes for Horner syndrome, with a focus on causes for acute isolated painful Horner syndrome, such as internal carotid artery dissection. Lastly, we discuss the workup, management, and potential complications of internal carotid artery dissection.

Ocular myasthenia typically causes intermittent or fluctuating ptosis and diplopia yet can be difficult to diagnose definitively. In this chapter, we begin by reviewing the symptoms and signs of ocular myasthenia. We next discuss the laboratory workup for antibodies that are associated with ocular myasthenia and describe bedside tests that can helpful for confirming the diagnosis. We then discuss electrophysiology testing that can be helpful, including repetitive nerve stimulation testing and single-fiber electromyography. Lastly we review the management options for ocular myasthenia, which include symptomatic treatments (such as pyridostigmine), immunosuppression (such as corticosteroids and steroid-sparing agents), and surgical treatments (such as eyelid and strabismus surgery).

Dysfunction of the optic chiasm typically produces bitemporal hemianopic visual field defects. Optic chiasmal dysfunction most often results from compression by extrinsic lesions, such as pituitary macroadenomas and meningiomas. In this chapter, we begin by describing the various bitemporal hemianopic visual field defects that can occur with optic chiasmal dysfunction. We next list potential causes of optic chiasmal dysfunction. We then review the clinical features and evaluation of pituitary apoplexy, which results from infarction of (or hemorrhage into) a pituitary macroadenoma. Lastly, we discuss the management of pituitary apoplexy, including the indications for and timing of surgical decompression, and review factors that affect the prognosis for visual recovery.

Carotid-cavernous fistulas are abnormal vascular communications between the carotid artery or its branches and the cavernous sinus. They often present with visual symptoms and signs, such as proptosis, chemosis, diplopia, or conjunctival injection. In this chapter, we begin by reviewing the types of carotid-cavernous fistula and their respective causes. We next discuss the symptoms, signs, and potential complications of carotid-cavernous fistula. We then discuss noninvasive imaging approaches for the diagnostic evaluation of carotid-cavernous fistula, although digital subtraction cerebral angiography is necessary for definitive diagnosis. Lastly, we review the management options for carotid cavernous fistula, including approaches that can minimize or address potential visual complications.

Optic neuritis is the most frequent cause of acute-onset optic neuropathy in young adults and is often encountered in clinical practice. In this chapter, we begin by reviewing the cardinal signs of optic neuropathy. We review the clinical characteristics and workup of optic neuritis. We review factors that increase the risk for developing multiple sclerosis. We discuss atypical clinical and imaging findings that should prompt further evaluation for other causes of optic neuritis, such as neuromyelitis optica. Lastly, we discuss the management options for optic neuritis, with reference to the findings from the Optic Neuritis Treatment Trial, and the prognosis for visual recovery.

Neuroretinitis is an inflammatory condition that results in acute painless monocular vision loss. It is characterized by unilateral optic disc edema with fluid extending from the peripapillary region into the macula. As the fluid resorbs, retinal exudates develop in a stellate configuration to produce a characteristic macular star. In this chapter, we begin by reviewing the clinical features of neuroretinitis. We next discuss potential causes of neuroretinitis, which includes infections (e.g., cat-scratch disease) and inflammatory disorders (e.g., sarcoidosis). We then discuss the laboratory workup of neuroretinitis. Lastly, we review the management options for neuroretinitis and factors influencing the prognosis for visual recovery.

Binocular horizontal diplopia with a unilateral abduction deficit is often due to sixth nerve palsy. However, it can also be caused by other conditions, such as medial rectus muscle restriction in thyroid eye disease. In this chapter, we begin by reviewing the differential diagnosis of an abduction deficit. We next list the common causes of an isolated unilateral sixth nerve palsy and bilateral sixth nerve palsy. We then discuss our approach to neuroimaging for sixth nerve palsy, as this remains a controversial topic. Lastly, we discuss the prognosis and management of sixth nerve palsy, with a focus on sixth nerve palsy due to microvascular ischemia.

Homonymous hemianopia is caused by unilateral lesions involving the retrochiasmal visual pathways or primary visual cortex. Common causes of homonymous hemianopia include stroke, tumor, and trauma. In this chapter, we begin by reviewing the clinical features that can help to localize the lesion and determine its cause. We next discuss the diagnostic evaluation of homonymous hemianopia, emphasizing the importance of formal visual field testing. We list causes of homonymous hemianopia that produce minimal or no abnormalities on neuroimaging, which include migraine, seizures, encephalopathies, and neurodegenerative disorders. Lastly, we discuss the implications of homonymous hemianopia for driving and strategies for rehabilitation.

Infranuclear ophthalmoplegia is characterized by global weakness of the extraocular and levator muscles. It has a broad differential diagnosis that varies depending on the tempo of onset. In this chapter, we begin by describing how to differentiate nuclear-infranuclear ophthalmoplegia from supranuclear ophthalmoplegia at the bedside. We next list the common causes of acute onset infranuclear ophthalmoplegia, which include Miller Fisher syndrome, Guillain-Barré syndrome, stroke, and ocular myasthenia. We then list the common causes of chronic progressive infranuclear ophthalmoplegia, which include mitochondrial disorders, oculopharyngeal muscular dystrophy, and myotonic dystrophy. We discuss the clinical features and diagnostic workup of chronic progressive external ophthalmoplegia due to mitochondrial disease. Lastly, we briefly discuss the management of ptosis and diplopia in the setting of chronic progressive external ophthalmoplegia.

Downbeat nystagmus is a common type of central vestibular nystagmus that often produces oscillopsia or blurred vision. It is a vertical jerk-waveform nystagmus with upward slow phases and downward quick phases. In this chapter, we begin by reviewing the clinical features of downbeat nystagmus. We next list the common causes for downbeat nystagmus, which include inherited cerebellar degenerations, acquired cerebellar degenerations, congenital hindbrain anomalies, stroke, tumors, and medications. We then discuss the workup and management of paraneoplastic cerebellar degeneration, which is most commonly associated with cancers of the lung, ovary, and breast. Lastly, we review medical treatment options for downbeat nystagmus.

Optic nerve compression results in progressive, and often painless, vision loss. In this chapter, we begin by reviewing the clinical features of anterior and posterior compressive optic neuropathy. We next review the common causes of compressive optic neuropathy, which include orbital tumors (e.g., optic nerve sheath meningioma, optic glioma, and capillary hemangioma), orbital infection, orbital inflammation, intracranial tumors (e.g., pituitary macroadenoma, meningioma, and craniopharyngioma), aneurysm, and thyroid eye disease. We then review the workup for compressive optic neuropathy and discuss the various imaging options. Lastly, we discuss the clinical features, imaging findings, management options, and prognosis for visual recovery for patients with optic nerve sheath meningioma.

Nonarteritic anterior ischemic optic neuropathy is the most frequent cause of acute-onset optic neuropathy in older adults. Its exact pathogenesis remains uncertain, although it often occurs in patients with a small, structurally congested optic disc (“disc at risk”). In this chapter, we begin by reviewing the clinical features of nonarteritic anterior ischemic optic neuropathy. We then discuss the prognosis for recovery of vision and fellow eye involvement. We review the risk factors and precipitating factors for this condition. We list the medications that have been associated with this condition. Lastly, we review the workup and management approach for this common condition.

A difference in the size of the pupils (anisocoria) is a frequent finding on physical examination. While often a cause for alarm, it is not uncommonly physiologic. In this chapter, we begin by reviewing the innervation of the iris sphincter and dilator muscles. We next introduce clinical strategies that can help to determine the etiology of anisocoria. We describe the components of the pupil examination, which includes an evaluation of pupil size in bright light compared to darkness, as well as evaluation of the pupil shape, response to light, and response to near. We include an algorithm that summarizes the clinical approach to anisocoria. Lastly, we review the clinical features of physiologic anisocoria, which occurs in up to 20% of the normal population and does not require further diagnostic testing.

Leber hereditary optic neuropathy in an important cause of acute painless monocular vision loss. It most often occurs in young men. Almost all patients develop fellow eye involvement within a few months, resulting in severe irreversible binocular vision loss. In this chapter, we begin by reviewing the differential diagnosis of acute optic neuropathy. We next discuss the genetic basis for Leber hereditary optic neuropathy and list the three common mitochondrial DNA mutations that cause it. We then review the clinical features and natural history of Leber hereditary optic neuropathy. Lastly, we discuss the treatment approach for this condition and review promising treatment options.

Pendular nystagmus often occurs in the setting of multiple sclerosis, but it can also occur in the syndrome of oculopalatal tremor. It has a sinusoidal waveform such that there are slow phases in both directions without corrective quick phases. Because it can cause disabling oscillopsia, many affected patients request treatment. In this chapter, we begin by reviewing the clinical features and pathogenesis of pendular nystagmus occurring in the setting of multiple sclerosis. We next review the clinical features and pathogenesis of oculopalatal tremor, which is most commonly a delayed consequence of brainstem tegmentum or cerebellar stroke. Lastly, we review the medical treatment options for pendular nystagmus, which include gabapentin and memantine.

Transient vision loss is common and often results from a transient loss of blood supply to the afferent visual system, although there are many other potential causes. In this chapter, we begin by listing the common causes of transient vision loss. We next discuss the approach to transient vision loss. We emphasize the importance of the history, since physical examination and workup may be unrevealing. We then review the diagnostic evaluation, with a focus on investigations for transient vision loss that is vascular in etiology. Lastly, we discuss the management approach for patients with a cardiac source of embolism or internal carotid artery stenosis.

Idiopathic intracranial hypertension is a syndrome of increased intracranial pressure of unknown cause that most often occurs in obese women of childbearing age, although it can also occur in children, men, and older adults. Papilledema is usually present and can cause irreversible vision loss if left untreated. In this chapter, we begin by reviewing the symptoms of this condition, which include headache, transient visual obscurations, and pulse-synchronous tinnitus. We next review the clinical signs and common findings on formal visual field testing. We then discuss the diagnostic evaluation and review the diagnostic criteria for this condition. Lastly, we review the goals and management of this condition, which must be tailored depending on the severity of symptoms, papilledema, and vision loss.

A tonic pupil is caused by a lesion affecting the postganglionic parasympathetic innervation of the pupil. It can be an incidental finding on examination or associated with visual symptoms, such as photophobia. In this chapter, we begin by briefly reviewing the differential diagnosis of photophobia. We next review the characteristic features of tonic pupil, which include poor pupil reaction to light, segmental palsy of the iris sphincter muscle, accommodation palsy, and tonic pupil reaction to near. We then review the causes of tonic pupil, which include viral infections, trauma, orbital surgery, or neurologic diseases, such as Miller Fisher syndrome. We then go on to discuss the clinical features, diagnostic evaluation, and prognosis of idiopathic tonic pupil, which is also known as an Adie pupil. Lastly, we briefly discuss the management options for tonic pupil, which include use of sunglasses and dilute pilocarpine eye drops.

We sought to determine, with a retrospective chart review, the imaging yield for patients with clinically isolated Horner syndrome. MRI/MRA of the head and neck extending from the supraorbital ridge to T4 with fat suppression and with postcontrast images was obtained. Of 88 patients with isolated Horner syndrome who were imaged, 20% had a causative etiology on imaging. The most common cause of an isolated Horner syndrome was a carotid artery dissection. There was 1 patient with a primary malignancy found to be the causative lesion in this group, and 1 patient with spread of their known metastatic disease.