Objective Assessment of Visual Field Defects Caused by Optic Chiasm and Its Posterior Visual Pathway Injury.

OBJECTIVES: To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury. METHODS: Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively. RESULTS: The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway. CONCLUSIONS: Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Objective Assessment of Visual Field Defects Caused by Optic Chiasm and Its Posterior Visual Pathway Injury / 法医学杂志

OBJECTIVES@#To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury.@*METHODS@#Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively.@*RESULTS@#The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway.@*CONCLUSIONS@#Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Information-processing speed in mildly disabled relapsing-remitting multiple sclerosis patients correlates with volumetry of optic chiasma and subcortical grey matter nuclei.

INTRODUCTION: Multiple sclerosis (MS) is an inflammatory demyelinating disease leading not only to physical disability but also to cognitive dysfunction. The aim of our study was to test cognitive functions of MS patients with mild relapsing-remitting form and to find out the relationship between cognitive functions and brain volumetry. METHODS: 52 patients (RRMSp) and 23 age-related healthy participants (CON) were enrolled. Mild disability was defined by mean EDSS 2.4 (≤ 4.0), and by median of disease duration 5.2 years. Cognitive status was tested using Single Digit Modality Test (SDMT). Brain volumetry was processed in FreeSurfer 2.0.0. RESULTS: RRMSp patients showed significantly lower SDMT score than CON. SDMT results correlated positively with volume of thalamus, putamen and nc. caudate, and negatively with optic chiasma volume. Compared with CON, RRMSp presented with significantly lower volume in left and right nc. accumbent, cuneus and insular GM, right putamen, total brain cortical grey matter (GM), white matters hypointensities, and 3rd ventricular widths. CONCLUSION: To our best knowledge, this is the first study that presents results showing a correlation of lower SDMT with higher optic chiasma volume, due to its subclinical chronic demyelination. We confirmed that GM atrophy is involved in cognitive functions in MS (Tab. 3, Fig. 2, Ref. 73).

A Case of Suprasellar, Intrasellar, and Infrasellar Meningioma Presenting as a Visual Field Defect in an Obese Female.

Bitemporal hemianopia is the most common visual field defect encountered in suprasellar meningiomas compressing the optic chiasma and its vascular supply. It is hard to distinguish between meningioma and tumors that arise from suprasellar, intrasellar, and infrasellar extensions. Clinical findings, hormonal levels, and radiological findings could help in labeling it as meningioma. A 53-year-old obese woman with a history of blurred vision more in the right eye, loss of smell, and a headache was diagnosed with meningioma having suprasellar, intrasellar, and infrasellar extension on neuroimaging. She developed bitemporal hemianopia, which gradually worsened over the course of six months with concomitant headaches and dizziness that was treated with analgesics leading to a delayed diagnosis. As she was symptomatic, it was decided to resect her tumor. The patient underwent an endoscopic transsphenoidal approach for tumor resection. Successful excision of the tumor was accomplished. Postoperatively on further evaluation, the patient's anosmia and the visual deficit were resolved. This instance shows that meningioma located in the sella can cause symptoms like anosmia and visual field loss, which should not be neglected. It also underlines the significance of visual field evaluation on a regular basis as this might predict radiological and symptomatic progression.

Comparative Evaluation of Two SD-OCT Macular Parameters (GCC, GCL) and RNFL in Chiasmal Compression.

Purpose: To evaluate the relationship between different macular thickness parameters analyzed by SD-OCT and the central visual field (VF) evaluated with automated kinetic perimetry in a cohort of patients with pituitary tumors. Methods: Data from patients with pituitary adenoma treated at Reims University Hospital between October 1st, 2017, and May 31st, 2018 were collected. All patients underwent an automated kinetic perimetry and a SD-OCT to map the ganglion cell complex (GCC), the ganglion cell layer (GCL) thickness and the retinal nerve fiber layer (RNFL) using devices from two different manufacturers. Univariate and multivariate analysis were used to evaluate the correlation between the area of central VF in square degrees (deg2) and the SD-OCT parameters (µm). Results: Eighty-eight eyes were included in the analysis. All the thickness parameters measured in SD-OCT decreased with the visual field alteration. The best correlation was observed between superior thickness parameters (GCC, GCL) and the inferior central visual field. The most pertinent predictive factors for visual field loss were the inferior central GCL and the nasal RNFL (both AUC=0.775) with a sensitivity respectively of 86% and 70%. Conclusion: This study suggests that both GCC, GCL thickness parameters could be reliable predictors of central visual field impairment in patients with pituitary tumors. There was no significative difference between both devices.

Awake Microsurgical Resection for Optochiasmatic Cavernous Malformation.

Cavernous malformations (CM) affect approximately 0.5% of the population, with only a limited portion being located in the optic nerve and chiasma. The clinical presentation is determined by their locations. In the optochiasmatic CM, the acute visual disturbance is the most common presentation. Chronically, many show a progressive visual loss, chronic headache, and pituitary disturbances. The differential diagnosis includes optic glioma, arteriovenous malformations, aneurysm, craniopharyngioma, pituitary apoplexy, and inflammatory conditions. In Video 1, we present the case of a 39-year-old woman with a history of a hemorrhagic optochiasmatic cavernoma in 2016, who started using propranolol to reduce the lesion and symptoms of visual loss. Moreover, the first microsurgical resection of the cavernoma and evacuation of the hematoma were performed in the same year. Owing to evolvement from a partial to a total vision loss in the left eye and presentation of new symptoms in the right eye, the patient underwent microsurgical resection. The surgery was performed sequentially. An awake craniotomy was performed to monitor the chiasma and right optic nerve. The postoperative magnetic resonance imaging showed complete resection of the CM, and the patient fully recovered. The patient signed the institutional consent form, stating that he or she accepts the procedure and allows the use of his or her images and videos for any type of medical publications in conferences and/or scientific articles.

[Neuro-computational approaches for objective assessment of visual function]. / Neurocomputationelle Ansätze zur objektiven Funktionsüberprüfung des Sehens.

BACKGROUND: Retinal pathologies affect the structure and function of post-retinal visual pathways. These post-retinal alterations bear the potential to obstruct the aim of innovative retinal treatment to restore visual function. OBJECTIVE: Current developments in the field of neuroimaging and the associated neurocomputational approaches enable a detailed assessment of this interrelationship. As a consequence, they open up the possibility to anticipate the success of treatment. METHODS: This review article demonstrates how innovations particularly in magnetic resonance imaging (MRI)-based anatomical, functional, and diffusion imaging can guide visual pathway assessments that are relevant for ophthalmological applications. RESULTS: Specific examples of retinal and visual pathway pathologies in the context of a detailed analysis of the visual pathway are described. CONCLUSION: A concept is introduced of how to translate the meaningful but technically and computationally challenging neuroimaging procedures into a clinical setting in order to effectively connect these procedures to innovative treatment approaches.

Black Holes in the Brain and Spine: A Dark Disease.

A 7-year-old girl presented with difficulty in walking and bilateral vision impairment since past 15 days. On examination, she had disc pallor, flaccid paraparesis with positive Babinski sign, and reduced sensations below clavicle. She was diagnosed as anti-aquaporin-4 (AQP-4)-positive neuromyelitis optica. This article emphasizes the importance of recognizing its classical neuroimaging findings distinct from other disorders.

Usefulness of MRI Slices Parallel to the Optic Chiasma in a Case with Traumatic Optic Nerve Avulsion after a Bear Attack.

Optic nerve avulsion is an exceedingly rare condition. Here, we describe a case of optic nerve avulsion in a 74-year-old man with temporal hemianopia in the contralateral eye after a bear attack. Magnetic resonance imaging (MRI) revealed separation of the optic nerve distal to the optic chiasma, whereas the high signal in diffusion-weighted imaging suggested nerve injury from the left side of the optic chiasma to the left optic tract. MRI slices parallel to the optic chiasma were obtained and used for evaluating the site of optic nerve avulsion and nerve injury, which were responsible for temporal hemianopia in the contralateral eye.

Resolution of symptomatic secondary empty sella syndrome following lumbar-peritoneal shunt.

BACKGROUND: Post-surgical empty sella is related to the removal of pituitary tumors either from the transcranial or transphenoidal route, rendering diaphragma sellae incompetent at the end of the procedure. This subsequently leads to herniation of the third ventricle and optic apparatus into the empty sella. Studies have shown that in 50% of the cases, individuals with primary and secondary empty sella syndrome have developed defects in the visual fields. Benign increased intracranial pressure, cerebrospinal rhinorrhea, papilledema, and abnormalities affecting visual acuity may also occur as a result of empty sella. CASE DESCRIPTION: This case report discusses a rare treatment option for the symptomatic secondary empty sella syndrome. Patient underwent lumbar drain placement and that resulted in astonishingly significant improvement in vision. Keeping in view the beneficial effect of lumbar drain, lumbar-peritoneal (LP) shunt was inserted which showed drastic improvement in vision. CONCLUSION: The surgical outcome of symptomatic cases of ESS is favorable. Various common surgical options were reported in literature; however, we have discussed an unconventional surgical option with an impressive outcome.

Traumatic chiasmal syndrome: A meta-analysis.

PURPOSE: To report a case presenting with bitemporal hemianopia due to traumatic chiasmal syndrome after head injury, and to compare the findings with individual case reports published in the literature. METHODS: A detailed search was made in PubMed, MedIND, Taylor and Francis online and Wiley online library databases for individual case reports of traumatic chiasmal syndrome. All the case reports were read in full and the findings summarized in a table, which included details of the case who presented with bitemporal hemianopia as an index case. RESULTS: All published cases of traumatic chiasmal syndrome appear to share some common features, such as injury to the frontal bone and fracture of the anterior skull base. Bitemporal hemianopia and visual acuity have a variable presentation, and do not appear to correlate with severity of injury. Isolated bitemporal hemianopia is rare and clinical improvement may or may not occur. CONCLUSIONS AND IMPORTANCE: Traumatic chiasmal syndrome should be considered as a differential diagnosis in patients presenting with bitemporal hemianopia after head injury causing frontal and anterior skull base fracture.

Vision loss in tuberculous meningitis.

Vision loss is a disabling complication of tuberculous meningitis. Approximately, 15% of survivors are either completely or partially blind. All structures of the visual pathway may be affected in tuberculous meningitis. Optic nerve and optic chiasma are most frequently and dominantly affected. Thick-gelatinous exudates lying over the base of brain, are the pathological hallmark of tuberculous meningitis and are responsible for almost all of its major complications, including vision loss. Strangulation of optic nerves and optic chiasma by the exudates, compression over optic chiasma by the dilated third ventricle, raised intracranial pressure, endarteritis, shunt failure, bacterial invasion of optic nerves and drug-induced optic nerve damage are important reasons that are considered responsible for vision loss. Prompt antituberculosis treatment is the best management option available. Immunomodulatory drugs and cerebrospinal fluid diversion procedures are of limited help. Early recognition and treatment of tuberculous meningitis is the only way forward to tackle this problem.

Cavernous malformation of the optic chiasm: Neuro-endoscopic removal.

Cavernous malformations (CMs) arising from the optic nerve and chiasm are extremely rare. In large autopsy series, CMs were estimated to range from 0.02 to 0.13% in the general population. However, with introduction of MRI, these lesions were found more often than previously thought, ranging from 0.2% to 0.4%. Only 29 cases have been reported according to our knowledge. Most patients present with drop in visual acuity and visual field. Although MRI findings of cavernous malformations have been reported, they may not be diagnostic enough. Among the 29 reported, 16 underwent total resection with good results. In some, resection was complicated by damage to the surrounding neural tissue. Surgical removal is the recommended treatment to restore or preserve vision and to eliminate the risk of future hemorrhage. However, the anatomical location and eloquence of nearby neural structures can make these lesions difficult to access and remove. CMs appear to occur in every age group (range 4 months to 84 years mean-34.6 years) ith an approximately equal male to female ratio. They typically present with chiasmal apoplexy, characterized by sudden visual loss, acute headaches, retro orbital pain, and nausea.

Prenatal ultrasonic research of fetal optic chiasma / 中华超声影像学杂志

Objective To research fetal optic nerve,optic chiasma and optic tract size using high resolution prenatal ultrasound,establish a scan method and the reference range of optic nerve,optic chiasma and optic tract in normal fetus.Methods Based on the section of circulus arteriosus cerebri,the probe were rotated to get the chiasma section for measuring the diameter of bilateral optic nerve,optic tract and area of optic chiasma in 453 normal fetus respectively.Used gestation age and corresponding biological parameters as independent variables,the regression equation was established analyse the gender differences.Results 26-33 weeks was the preferable gestational age to visualize the chiasma section.It had good repeatability except chiasma area.The bilateral optic nerve and optic tract diameter,optic chiasma diameter and area had an increased along with the gestational age reposefully.There was no significant difference between the two sides of optic nerve and the gender.Conclusions Prenatal ultrasound can assess the size and shape of fetal optic nerve,optic chiasma and optic tract.The normal reference range,established by ultrasound,is helpful to diagnose the abnormality of optic chiasma.

Effects of hypocretin and norepinephrine interaction in bed nucleus of the stria terminalis on arterial pressure.

Forebrain neuronal circuits containing hypocretin-1 (hcrt-1) and norepinephrine (NE) are important components of central arousal-related processes. Recently, these two systems have been shown to have an overlapping distribution within the bed nucleus of the stria terminalis (BST), a limbic structure activated by stressful challenges, and which functions to adjust arterial pressure (AP) and heart rate (HR) to the stressor. However, whether hcrt-1 and NE interact in BST to alter cardiovascular function is unknown. Experiments were done in urethane-α-chloralose anesthetized, paralyzed, and artificially ventilated male Wistar rats to investigate the effect of hcrt-1 and NE on the cardiovascular responses elicited by l-glutamate (Glu) stimulation of BST neurons. Microinjections of hcrt-1, NE or tyramine into BST attenuated the decrease in AP and HR to Glu stimulation of BST. Additionally, combined injections of hcrt-1 with NE or tyramine did not elicit a greater attenuation than either compound alone. Furthermore, injections into BST of the α2-adrenergic receptor (α2-AR) antagonist yohimbine, but not the α1-AR antagonist 2-{[ß-(4-hydroxyphenyl)ethyl]aminomethyl}-1-tetralone hydrochloride, blocked both the hcrt-1 and NE-induced inhibition of the BST cardiovascular depressors responses. Finally, injections into BST of the GABAA receptor antagonist bicuculline, but not the GABAB receptor antagonist phaclofen, blocked the hcrt-1 and NE attenuation of the BST Glu-induced depressor and bradycardia responses. These data suggest that hcrt-1 effects in BST are mediated by NE neurons, and hcrt-1 likely acts to facilitate the synaptic release of NE. NE neurons, acting through α2-AR may activate Gabaergic neurons in BST, which in turn through the activation of GABAA receptors inhibit a BST sympathoinhibitory pathway. Taken together, these data suggest that hcrt-1 pathways to BST through their interaction with NE and Gabaergic neurons may function in the coordination of cardiovascular responses associated with different behavioral states.

Reduced responsiveness of kisspeptin neurons to estrogenic positive feedback associated with age-related disappearance of LH surge in middle-age female rats.

Age-related disappearance of the LH surge is one of major biomarkers of reproductive aging in female rats. Kisspeptin neurons in the hypothalamic anteroventral periventricular nucleus (AVPV) are proposed as the critical regulator of the preovulatory LH surge in response to estrogenic positive feedback. Here we investigated the possible involvement of the AVPV kisspeptin neurons in the disappearance of the LH surge in middle-age rats. Middle-age rats exhibiting persistent estrus (M-PE) did not show an LH surge although neither Kiss1 mRNA nor peptide in the AVPV was differentially expressed when compared to young rats exhibiting normal estrous cycles (YN). M-PE released LH in response to exogenous kisspeptin in a similar dose-dependent manner as YN, suggesting that their GnRH neurons still maintained responsiveness to kisspeptin. To investigate the estrogenic positive feedback effect on kisspeptin neurons in the AVPV, rats were ovariectomized and supplemented with estradiol (OVX+E2). We performed in situ hybridization and immunohistochemistry for Kiss1 mRNA and cFos, respectively, and found that M-PE exhibited a significantly lower percentage of Kiss1 mRNA positive neurons with cFos immunoreactivity, although the total number of kisspeptin neurons was not different from that in cyclic rats. Furthermore, OVX+E2 M-PE did not show the surge-like LH release under high estradiol administration while YN did. Thus our current study suggests that the reduced responsiveness of the AVPV kisspeptin neurons to estrogenic positive feedback presumably results in the decrease in kisspeptin secretion from neurons and eventually causes the age-related disappearance of the LH surge in middle age female rats.

Optic chiasm B-cell lymphoma in a 20-month-old Mastiff dog.

A 20-month-old intact female Mastiff dog presented for evaluation of acute blindness. Computed tomography confirmed a tumor involved the optic chiasm and optic nerves. A B-cell lymphoma was confirmed with postmortem examinations. This case report documents a central nervous system neoplasm in a young dog.

Anatomy of the optic chiasma and its surrounding structures in saddle area operation / 中国综合临床

Objective To provide morphological evidences for visual field defect caused by the compression of the saddle area tumors.Methods The shape and position of the optic chiasma and its surrounding saddle diaphragm,pituitary,internal carotid artery,and perforating arteries of optic chiasma were studied from 80 adult.Results Its maximum angle was 100° in anterior horn with prechiasmatic space, and minimum angle was 40° with postfixed optic chiasma.The area of optic chiasma averaged(1.32±0.04)cm2,the thickness of saddle diaphragm was 0.58 mm,and about 5% of saddie diaphragm did not exist.The foramen of saddle diaphragm pushed into the opposite side was 52.5%,and the maximum diameter was 7.8 mm×9.8 mm.The pituitary was found inferior to the saddle diaphragm foramen in 78%(62/80).In 76.3%(61/80) brains,the carotid artery touched chiasm opticum.Conclusions Visual field defect caused by compression from pituitary tumor and craniopharyngioma is directly related with the shape of the optic chiasma and its surrounding structures.