Neuro-ophthalmology

Paralysis of the sixth cranial nerve (abducens nerve) causes dysfunction of the lateral rectus muscle, leading to paralytic esotropia and ipsilateral diplopia. Ischemia due to diabetes and hypertension is the most common cause, but the frequency of tumors is higher than in other ocular motor nerve palsies.

An acute autoimmune demyelinating disease triggered by infection or vaccination. It causes multifocal lesions in the brain and spinal cord, presenting with encephalopathy, optic neuritis, motor paralysis, etc. Common in children but also occurs in adults.

Adie's pupil (tonic pupil) is a condition in which the light reflex is absent or diminished due to a lesion of the ciliary ganglion, but the near response is preserved. It is common in young women and is characterized by vermiform movements of the pupil and light-near dissociation.

A condition in which vision in one eye transiently decreases and recovers within seconds to minutes. The most common cause is thromboembolism from internal carotid artery disease, and it can be a precursor to stroke, requiring urgent evaluation.

Optic neuropathy occurring as an ocular side effect of the antiarrhythmic drug amiodarone. It is characterized by insidious vision loss and persistent optic disc edema, and differentiation from nonarteritic anterior ischemic optic neuropathy (NAION) is important.

Anisocoria is a condition in which the pupil sizes differ between the two eyes, with causes ranging from physiological to life-threatening diseases. It is important to differentiate between sympathetic and parasympathetic nerve disorders and drug-induced causes, and to perform appropriate evaluation and management.

Myasthenia gravis in which both anti-acetylcholine receptor antibodies and anti-MuSK antibodies are negative (double seronegative MG). Ocular symptoms are predominant, often occurring in children and young adults, and presents specific challenges in testing and diagnosis.

A pupillary abnormality characterized by the triad of miosis, loss of light reflex, and preserved near reflex. Classically caused by neurosyphilis (tabes dorsalis), but in modern times it is often associated with diabetes, cerebrovascular disease, and demyelinating diseases. The lack of response to low-concentration pilocarpine is an important distinguishing feature from Adie's pupil.

An ischemic disease of the optic nerve associated with giant cell arteritis (GCA). It causes sudden severe vision loss, and emergency treatment with high-dose steroids is essential to prevent progression to the fellow eye.

Autoimmune-related retinopathy and optic neuropathy (ARRON) is a rare disease in which autoimmune retinopathy and optic neuropathy occur together without malignancy. Because its clinical presentation is similar to cancer-associated retinopathy (CAR), it requires exclusion diagnosis.

Autosomal dominant optic atrophy (ADOA) is the most common hereditary optic neuropathy, primarily caused by OPA1 gene mutations, characterized by slowly progressive bilateral visual loss and optic atrophy starting in childhood.

Carotid-cavernous fistula (CCF) is an abnormal vascular connection between the internal carotid artery or external carotid artery and the cavernous sinus. The triad includes pulsatile exophthalmos, conjunctival chemosis, and vascular bruit. Endovascular treatment is the first-line therapy.

A syndrome presenting with ophthalmoplegia, facial sensory disturbance, and Horner syndrome due to lesions of the cavernous sinus. The most common cause is tumor, but vascular, inflammatory, and infectious lesions are also important differential diagnoses.

A rare benign neuronal tumor (WHO grade II) that commonly occurs in the lateral ventricle. It predominantly affects young adults aged 20-40 and presents with symptoms of increased intracranial pressure due to obstructive hydrocephalus. Total resection is the standard treatment, and the prognosis is favorable.

Cerebral venous and dural sinus thrombosis (CVST) is a blood clot in the cerebral venous drainage system, causing papilledema and visual impairment due to increased intracranial pressure. It is a rare disease accounting for 0.5–3% of all strokes.

A disease in which the extraocular muscles are selectively impaired due to mitochondrial dysfunction, leading to slowly progressive bilateral ptosis and ophthalmoplegia. It is classified into isolated CPEO and CPEO-plus with systemic symptoms.

A general term for conditions in which multiple cranial nerves are simultaneously affected due to brainstem (midbrain, pons, medulla oblongata) lesions, presenting with various ocular motor disturbances, nystagmus, and pupillary abnormalities. Causes include cerebrovascular disease, demyelinating diseases, and inflammatory diseases, with characteristic symptom patterns depending on the lesion site.

Follicular dendritic cell sarcoma (FDCS) is an extremely rare low-grade sarcoma that occurs intracranially or intraorbitally. Invasion of the cavernous sinus or clivus can cause ocular symptoms such as diplopia, visual loss, proptosis, and ptosis.

A disease in which inflammation of cranial nerves causes nerve destruction or demyelination. Causes are diverse, including infectious, autoimmune, neoplastic, vascular, and idiopathic. When multiple cranial nerves are affected, it is called polyneuritis cranialis.

Toxic optic neuropathy caused as a side effect of the antituberculosis drug ethambutol. Characterized by bilateral, painless vision loss and color vision abnormalities. Early detection and drug discontinuation determine visual prognosis.

A disease caused by dysfunction of the fourth cranial nerve (trochlear nerve) that innervates the superior oblique muscle, resulting in hypertropia, excyclotorsion, and vertical diplopia on the affected side. Trauma, ischemia, and congenital causes are the main etiologies, and the Bielschowsky head tilt test is useful for diagnosis.

A disease caused by dysfunction of the fourth cranial nerve (trochlear nerve) that innervates the superior oblique muscle, resulting in ipsilateral hypertropia, excyclotorsion, and vertical diplopia. Trauma, ischemia, and congenital causes are the main etiologies, and the Bielschowsky head tilt test is useful for diagnosis.

Optic neuritis occurring as a rare complication of herpes zoster ophthalmicus (HZO). Varicella-zoster virus (VZV) damages the optic nerve, causing vision loss.

Horner syndrome is a syndrome characterized by the triad of miosis, ptosis, and anhidrosis due to disruption of the ocular sympathetic pathway. It is classified into central, preganglionic, and postganglionic types, and is diagnosed by pharmacological pupil testing and the apraclonidine test. It is essential to rule out serious causes such as carotid artery dissection and Pancoast tumor.

An inflammatory disease of the optic nerve caused by autoimmune mechanisms. It predominantly affects women aged 15–45 years, with acute unilateral vision loss and eye movement pain as main symptoms. Visual recovery is expected in over 90% of cases, but anti-AQP4 antibody-positive cases are refractory, and assessment of MS conversion risk is important.

Internuclear ophthalmoplegia (INO) is an eye movement disorder caused by a lesion of the medial longitudinal fasciculus (MLF), characterized by impaired adduction on the ipsilateral side, nystagmus of the contralateral abducting eye, and preserved convergence. When MLF lesion is combined with PPRF/abducens nucleus lesion, one-and-a-half syndrome occurs, with only abduction of the contralateral eye remaining. Multiple sclerosis and cerebrovascular disease are the two main causes, and treatment of the underlying disease is fundamental.

An acute to subacute optic neuropathy with maternal inheritance due to mitochondrial DNA point mutations. It predominantly affects young males, causing severe bilateral vision loss and central scotomas. The mt11778 mutation is most common, and visual prognosis is poor, but new treatments such as idebenone and gene therapy are being developed.

A pupillary sign in which the light reflex is impaired while the near reflex is preserved. It is caused by afferent pathway defects, midbrain dorsal lesions, efferent pathway defects, and aberrant regeneration, and is observed in conditions such as Adie tonic pupil, Argyll Robertson pupil, and Parinaud syndrome.

A central nervous system demyelinating disease caused by autoantibodies against myelin oligodendrocyte glycoprotein (MOG). Its main phenotypes are optic neuritis, ADEM, and myelitis. It is a disease concept independent of MS and AQP4-positive NMOSD. International diagnostic criteria were established in 2023.

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system that presents with various ocular symptoms such as optic neuritis and internuclear ophthalmoplegia. Diagnosis is based on the McDonald criteria, including MRI and cerebrospinal fluid analysis, and management involves steroid pulse therapy and disease-modifying therapies.

Chordoma is a rare malignant bone tumor arising from notochordal remnants. When it occurs at the skull base, it presents with neuro-ophthalmologic symptoms such as abducens nerve palsy, diplopia, and visual field defects. This article explains diagnosis, treatment, and prognosis.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system mediated by aquaporin-4 antibodies, characterized primarily by optic neuritis and myelitis.

A disease in which the optic nerves in both eyes are damaged due to deficiencies of nutrients such as B vitamins and copper. Risk factors include bariatric surgery, vegan diet, and alcoholism.

This article explains the diagnosis and treatment of ocular myasthenia gravis, a form of myasthenia gravis (an autoimmune disease of the neuromuscular junction) that is limited to extraocular muscle symptoms such as ptosis and diplopia. It is characterized by diurnal fluctuation and easy fatigability, and early treatment is important to prevent progression to the generalized form.

Moyamoya disease (MMD) is a chronic cerebrovascular disorder characterized by progressive stenosis of the terminal portion of the internal carotid artery, and may present with ocular symptoms such as transient monocular vision loss, central retinal artery occlusion, ocular ischemic syndrome, and morning glory syndrome.

A disorder caused by damage to the oculomotor nerve (cranial nerve III), leading to ptosis, impaired eye movement, and pupillary dilation. Main causes include aneurysm, ischemia, trauma, and tumors. If pupillary dilation is present, urgent imaging is required.

A horizontal eye movement disorder caused by a pontine lesion. It combines ipsilateral horizontal gaze palsy ("1") with ipsilateral internuclear ophthalmoplegia ("0.5"), resulting in a characteristic syndrome where only abduction of the contralateral eye is preserved.

This article explains the characteristics of visual impairment caused by craniopharyngioma, the mechanism of optic chiasm compression, and diagnosis and treatment.

Calcified deposits within the optic nerve head. There are superficial and buried types; buried type requires differentiation from papilledema. Prevalence is 0.41–2.0%, usually asymptomatic, but visual field abnormalities are found in over 70% of cases, requiring management as a chronic progressive optic nerve disease.

This article provides an overview, diagnosis, and treatment of congenital optic disc excavation anomalies, including optic disc coloboma, morning glory syndrome, peripapillary staphyloma, and optic disc pit.

A benign tumor arising from the meninges of the optic nerve, characterized by slowly progressive unilateral vision loss. MRI shows a characteristic tram-track sign, and the first-line treatment is radiotherapy.

Optic neuritis associated with multiple sclerosis (MS) is characterized by acute unilateral painful vision loss and may be the initial symptom of MS. Diagnosis is made using MRI and cerebrospinal fluid analysis based on the McDonald criteria, and management includes steroid pulse therapy and disease-modifying therapies. Differentiation from MOGAD and NMOSD is important.

An inflammatory and demyelinating disease of the optic nerve that occurs or relapses during pregnancy or postpartum. The incidence increases after delivery due to immune rebound, with acute vision loss and eye movement pain as main symptoms.

Optic neuropathy occurring as an immune-related adverse event of immune checkpoint inhibitors (ICIs) used in immunotherapy for malignant tumors. Steroid treatment and decisions regarding continuation or discontinuation of ICIs are important.

An orbital inflammatory disease in which inflammation is confined to the optic nerve sheath. It presents with eye pain and various visual symptoms. MRI findings of tram-track sign and doughnut sign are key to diagnosis. It responds rapidly to steroid therapy, but caution is needed for recurrence during dose reduction.

A comprehensive overview of the classification, symptoms, diagnosis, and treatment of orbital masses. It covers a wide range of etiologies from benign lymphoproliferative disorders to life-threatening malignant tumors, and describes a diagnostic approach centered on imaging and pathological examination.

Bilateral optic disc swelling secondary to increased intracranial pressure. It is a warning sign of brain tumors, cerebral venous thrombosis, idiopathic intracranial hypertension (IIH), and other conditions. If untreated, it can lead to optic atrophy and irreversible vision loss.

A comprehensive explanation of bilateral optic disc swelling (papilledema) secondary to increased intracranial pressure and its most common cause, idiopathic intracranial hypertension (IIH), including definition, epidemiology, diagnosis, Frisén classification, treatment, fulminant type, and management during pregnancy.

Pharmacologic mydriasis is pupillary dilation caused by drugs such as anticholinergics or adrenergic agonists. It is important to differentiate it from life-threatening oculomotor nerve palsy, and a stepwise diagnosis using the pilocarpine test is required.

A tumor arising from the glandular cells of the anterior pituitary. It can cause bitemporal hemianopsia due to compression of the optic chiasm and may be accompanied by systemic symptoms due to hormone hypersecretion.

A disease causing acute vision loss due to ischemia of the optic nerve posterior to the lamina cribrosa. There are three types: arteritic, non-arteritic, and perioperative; the perioperative type often leads to severe and irreversible visual impairment.

A brain edema syndrome triggered by hypertension, immunosuppressants, eclampsia, etc. It presents with headache, seizures, and visual disturbances. It is often reversible, but about 10–20% of cases leave permanent neurological sequelae.

Pupillography is a test method that combines an infrared video camera and computer software to quantitatively record and measure pupillary responses. It objectively evaluates parameters such as the pupillary light reflex, dilation dynamics, and PIRP, and is clinically applied in a wide range of fields including ophthalmology, neurology, and pharmacology.

A benign cystic lesion arising from anatomical remnants during pituitary development. Often asymptomatic, but enlargement can cause headache, visual field defects, and endocrine dysfunction.

A clinical sign detected as a difference in pupillary response between the two eyes when light is shone into each eye separately. It indicates unilateral or asymmetric optic nerve or retinal damage and is useful for early detection of many important diseases, including emergencies.

The reverse RAPD test is a procedure to detect an afferent pupillary defect (RAPD) by observing the healthy eye when the other eye has an efferent pupillary defect. This allows evaluation of RAPD even in patients with combined efferent and afferent defects.

A rapid eye movement that shifts the point of fixation from one part of the visual field to another. The maximum speed is approximately 700°/second, and it is also attracting attention as an early diagnostic indicator of neurodegenerative and psychiatric diseases.

A general term for involuntary rapid eye movements (saccades) that interrupt fixation. Includes several types such as square-wave jerks, ocular flutter, and opsoclonus, and can be a sign of serious underlying diseases such as neurodegenerative disorders, demyelinating diseases, and paraneoplastic syndromes.

An extremely rare and rapidly progressive malignant tumor arising in the nasal cavity and paranasal sinuses. It rapidly invades the orbit and skull base, causing ocular symptoms such as diplopia, visual impairment, and proptosis. Definitive diagnosis is made by histopathological examination.

An acquired vertical misalignment of the eyes due to an imbalance in vestibular input caused by damage to the supranuclear otolith-ocular pathway. It is an important sign of posterior fossa lesions such as stroke and demyelinating disease, and clinical differentiation from trochlear nerve palsy is extremely important.

A hemodynamic condition in which stenosis or occlusion of the subclavian artery proximal to the origin of the vertebral artery causes retrograde blood flow in the ipsilateral vertebral artery. It presents with symptoms of vertebrobasilar insufficiency such as dizziness, diplopia, and transient visual disturbances.

A rare disease in which a thrombus forms in the superior ophthalmic vein. Causes include infection, inflammation, trauma, and blood coagulation abnormalities. It presents with proptosis, conjunctival chemosis, and ophthalmoplegia. There is a risk of progression to cavernous sinus thrombosis.

Superior segmental optic nerve hypoplasia (SSONH) is a congenital disorder characterized by a localized reduction of retinal ganglion cells in the superior portion of the optic disc, also known as "topless optic disc." It is strongly associated with maternal diabetes, and its prevalence in Japan is approximately 0.3%.

A rare autoimmune microangiopathy affecting precapillary arterioles of the brain, retina, and inner ear. Characterized by the triad of encephalopathy, branch retinal artery occlusion, and sensorineural hearing loss, most common in women aged 20–40.

Tadpole pupil is a rare paroxysmal condition in which the pupil becomes tadpole-shaped due to segmental spasms of the iris dilator muscle. It occurs most often in healthy young women, and attacks typically resolve spontaneously within 5 minutes. It is a benign condition that does not require specific treatment.

Optic nerve dysfunction associated with thyroid eye disease (TED), primarily caused by compression of the optic nerve due to enlargement of extraocular muscles and orbital fat. It occurs in 3–8% of all TED cases, and prompt diagnosis and treatment are key to visual recovery.

A rare disease characterized by unilateral severe retro-orbital pain and ophthalmoplegia (painful ophthalmoplegia) due to idiopathic granulomatous inflammation of the cavernous sinus, superior orbital fissure, or orbital apex. It is notable for a dramatic response to steroids, but careful attention is required as it is a diagnosis of exclusion.

A comprehensive explanation of toxic optic neuropathy, in which the anterior visual pathway is damaged by exposure to chemical substances or drugs. Details the causative agents, symptoms, diagnosis, treatment, and prognosis, with a focus on ethambutol.

A disease in which the optic nerve in the optic canal is damaged by indirect force from blunt trauma to the eyebrow area. It causes severe visual impairment immediately after injury, and early steroid pulse therapy affects the prognosis.

1.5 syndrome (horizontal gaze palsy + internuclear ophthalmoplegia) combined with ipsilateral peripheral facial nerve palsy, caused by a lesion in the dorsal pontine tegmentum. Main causes are cerebrovascular disorders and demyelinating diseases; localization diagnosis is possible from clinical findings.