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BACKGROUND In patients with sellar or parasellar tumors, it is crucial to evaluate visual field impairment in the preoperative stage and to predict visual field improvement after the surgery. The purpose of this study was to investigate the associations of diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) parameters in the optic radiations with preoperative and postoperative visual field impairment. METHODS This prospective study included 81 participants with sellar or parasellar tumors. Multishell diffusion imaging and a visual field impairment score (VFIS) were acquired before and after the surgery. The multishell diffusion-weighted imaging was acquired to measure the neurite density and neurite orientation dispersion, as well as the diffusivity. DTI parameters were fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD). NODDI provided intracellular volume fraction (Vic), the orientation dispersion index, and isotropic volume fraction (Viso). The associations of DTI and NODDI parameters in the optic radiations with VFIS were investigated, adjusting for age, tumor height, and symptom duration. RESULTS Among 162 optic radiations, 117 were functionally impaired in the preoperative stage. FA and Vic had significant negative correlations, whereas MD and RD had significant positive correlations with the VFIS (all P < 0.001). In the preoperative stage, lower FA (P = 0.001; odds ratio = 0.750) and Vic (P = 0.003; OR = 0.827) and higher MD (P = 0.007; OR = 1.244) and RD (P < 0.001; OR = 1.361) were significantly associated with the presence of visual field impairment. For the degree of postoperative improvement, preoperative lower Vic (P = 0.034; OR = 0.910) and higher MD (P = 0.037; OR = 1.103) and RD (P = 0.047; OR = 1.090) were significantly associated with more postoperative improvement. CONCLUSIONS DTI and NODDI parameters in the optic radiations were correlated with VFIS and associated with preoperative visual field impairments and postoperative improvement. It may help in predicting visual field improvement after the surgery in patients with sellar or parasellar tumors.

First described in 1991 and introduced into clinical practice in 1996, optical coherence tomography (OCT) now has a very extensive role in many different areas of ophthalmological practice. It is non-invasive, cheap, highly reproducible, widely available and easy to perform. OCT also has a role in managing patients with neurological disorders, particularly idiopathic intracranial hypertension. This review provides an overview of the technology underlying OCT and the information it can provide that is relevant to the practising neurologist. Particular conditions discussed include papilloedema, optic disc drusen, multiple sclerosis and neuromyelitis optica, other optic neuropathies, compression of the anterior visual pathway and various neurodegenerative conditions.

Background Allergic fungal rhinosinusitis (AFRS) is a common condition in which sinusitis develops as an IgE-mediated response to common sinonasal fungal organisms. If that response leads to blockage of sinus ostia, bone expansion and erosion by expansive cysts containing dense inspissated debris may occur with the potential for critical neurovascular compression including damage to the anterior visual pathway. Methods Review of clinical and imaging features of 2 patients who sustained catastrophic clinical outcomes. Results The first patient had pansinusitis with massive mucocele-like cysts expanding the sphenoid sinus and cranial base and causing compression of the anterior visual pathway that led to persistent severe vision loss despite extensive sinus surgery. The second patient developed sphenoethmoidal expansion with a marked inflammatory response and presumed conversion to invasive fungal sinusitis that caused anterior visual pathway vision loss, bilateral ocular motor palsies from extension into the cavernous sinuses, and death from a large middle cerebral artery stroke. Conclusions Although AFRS is most often benign and treatable, it may rarely produce catastrophic outcomes, especially if the sphenoid sinus is involved. Irreversible vision loss may occur from compression, and ocular motor palsies and death from conversion to invasive fungal disease. Close ophthalmologic and imaging monitoring is necessary in patients with expanded sinuses, and prophylactic sinus surgery may be indicated in certain cases.

Pituitary tumours are a common cause of functional impairment and degeneration of the anterior visual pathway. Depending on localization and size, they clinically manifest as initially reversible visual field defects. As part of interdisciplinary tumour management, ophthalmologic examinations are of particular importance concerning diagnostics, indication for tumour resection and documentation of functional surgical results. Based on the relationship between clinical dysfunction and manifest atrophy, together with the patient's age and the duration of symptoms, the ophthalmologist can provide insights into the postoperative visual prognosis. Under good conditions, surgical tumour resection often results in significant improvements to visual fields and acuity. Long-term ophthalmological controls are required in cases of persistent visual loss, radiotherapy or tumour remnants abutting the visual pathway.Hypophysentumoren sind ein häufiger Grund für Funktionseinschränkungen und Degeneration der vorderen Sehbahn. Bei entsprechender Lokalisation und Größe äußern sie sich durch zunächst reversible Gesichtsfelddefekte. Im interdisziplinären Tumormanagement kommt der augenärztlichen Untersuchung bei der Diagnosesicherung, Indikationsstellung zur Tumorresektion und Dokumentation des Therapieerfolges eine besondere Bedeutung zu. Anhand des Verhältnisses zwischen klinischer Dysfunktion und manifester Atrophie, gemeinsam mit dem Patientenalter und der Symptomdauer, kann der Augenarzt Aussagen zur Prognose des postoperativen Sehvermögens treffen. Bei guten Voraussetzungen zeigt sich hier oft bereits früh eine deutliche Gesichtsfeld- und ggf. eine Visusverbesserung. Langzeitkontrollen sind bei persistierender Sehminderung, Strahlentherapie oder Tumorresten mit Nähe zur Sehbahn erforderlich.

Optic nerve sheath meningiomas (ONSMs) are rare, benign neoplasms of the anterior visual pathway. The optimal modality of radiotherapy for treatment has not yet been established. This is the first study to show significant difference in visual outcomes between radiotherapy subtypes in the management of ONSM. We performed a retrospective analysis of visual outcomes and side effects in ONSM patients treated with radiotherapy at three centres in Sydney, Australia, between 2000 and 2016. 15 patients with ONSM were included, and visual outcomes (visual acuity, visual fields, colour vision, OCT retinal nerve fibre layer thickness and radiological tumour response) and treatment toxicities were assessed. Pooled data analysis of available studies was also performed. Statistical analysis was performed with binomial, two-tailed chi-squared tests and Fisher exact tests. In our cohort a significant majority experienced improved visual field (p = 0.046), stable or improved visual acuity (p = 0.0017) and colour vision (p = 0.015) after fractionated radiotherapy. Pooled analysis with strict inclusion criteria found 3D conformal radiotherapy to offer significantly poorer visual acuity compared to fractionated stereotactic radiotherapy (p = 0.008). When all published studies were included, stereotactic radiosurgery was superior to 3D conformal methods (p = 0.035), and equivalent to other fractionated methods. 3D conformal methods also had significantly higher rates of long-term side effects. These results support the use of fractionated radiotherapy and radiosurgery for ONSM treatment, however 3D conformal methods cannot be recommended.

We present the case of a 78-year-old patient with a large right internal carotid artery aneurysm found incidentally after 2-weeks of blurry vision without headache. The patient underwent endovascular coiling of the aneurysm with flow diverting stent placement for vessel reconstruction. The patient developed a left homonymous hemianopia two weeks after treatment. Magnetic resonance imaging demonstrated aneurysm expansion with perianeurysmal edema in the thalamus, basal ganglia and mild compression of the optic chiasm. The patient was started on high dose dexamethasone and his vision slowly improved over the next several months. This is a rare case of expansion of a coiled large cerebral aneurysm with mass effect on the anterior visual pathway.

Background Meningioma arising from locations in the vicinity of optic nerve or chiasm may affect the visual function which sometimes the presentation of such tumors. Decompression of the optic nerve or chiasm can give a chance to the visual function to recover. Methods 30 patients who had visual function affection and underwent meningioma excision are followed up for a period of one year with regular follow of their visual function periodically. Results In this study, females were more prevalent than males, 24 out of 30, age ranged from 24 to 72 years at the time of surgery, half the patients (15) presented with visual deterioration, the other patients presented with headache, seizure, proptosis or accidentally discovered. 22 patients improved concerning their visual function over time, 6 patients had stationary course and 2 patients deteriorated postoperatively. Conclusion Follow up of patients after surgical excision of meningioma compressing the anterior optic pathway showed gradual improvement in vision in follow up period up to one year, although the improvement in visual function showed a surge in early postoperative period, with continuous less steep improvement afterwards till the end of the observation period. Surgical excision of meningiomas compressing the anterior visual pathway give chance for recovery of visual function, more in younger patients, patients with shorter period of visual deterioration, patients with mild affection of the preoperative visual status. No statistically significant influence of tumor site, size, degree of excision and surgical approach on the postoperative visual outcome in this series.

Background Most anterior visual pathway meningiomas (AVPM) are benign and slow-growing, but these tumors may affect visual functions, including visual acuity (VA) and visual field (VF). Due to location, most are treated non-surgically by fractionated stereotactic radiotherapy (FSRT), aiming to prevent tumor progression and visual functions deterioration. Unfortunately, FSRT in itself may affect visual functions. The current preferred treatment regimen (in terms of safety and effectiveness) is undetermined. While most cases are treated with conventional fractionation (cFSRT)—50.4–54 Gy in 28–30 fractions of 1.8–2 Gy, advances in technology have allowed shortening of total treatment length to hypofractionation (hSRT)—25-27 Gy in 3–5 fractions of 5–9 Gy. Our aim was to evaluate the association of radiotherapy regimen for treating AVPM (cFSRT vs. hSRT) with visual function outcomes (VA, VF) at the last neuro-ophthalmologic evaluation. Methods We conducted a retrospective cohort study of AVPM cases treated at Sheba Medical Center during 2004–2015. We compared cFSRT and hSRT regimens regarding visual function (VA, VF) outcomes at the last neuro-ophthalmologic evaluation. VA was determined by the logarithm of the minimum angle of resolution (LogMAR). VF was determined by the mean deviation (MD). A clinically relevant change in VA was defined as 0.2 LogMAR. Results 48 patients (13 receiving hSRT, 35 receiving cFSRT) were included, with a median follow-up of 55 months. No significant difference was evident regarding LogMAR or MD of involved eyes at the last evaluation. Six (17%) patients in the cFSRT group experienced clinically relevant VA deterioration in the involved eye, compared with six (46%) in hSRT (p = 0.06). Conclusion Our findings, using comprehensive and meticulous investigation of visual outcomes, suggest that hSRT may be associated with higher risk for VA and VF deterioration in AVPM especially in ONSM. We recommend the use of cFSRT for ONSM.

The endoscopic endonasal approach (EEA) has become increasingly employed in the treatment of suprasellar meningiomas. These tumors often cause visual symptoms due to compression of the anterior visual pathway. We aimed to examine long-term visual outcomes after EEA for optic nerve decompression and resection of suprasellar meningioma at our center, and to identify preoperative factors predictive of postoperative visual improvement. We performed a retrospective cohort study on 27 patients who underwent the EEA for resection of meningiomas extending into the suprasellar cistern and decompression of anterior visual pathway between January 1, 2005, and March 1, 2019. We treated 8 male and 19 female patients, with a mean follow-up of 7.6 years. The mean age of our patients at initial presentation was 60.1 years. Eighteen patients (66.7%) presented with visual acuity deficits, and 12 (44.4%) patients presented with visual field deficits. Postoperatively, 11 patients had improved visual acuity, 6 had stable visual acuity, and 1 patient had slow and progressive decline of visual acuity; 5 patients had improved visual field, 6 had stable visual field, and 1 patient had slow and progressive decline in visual field. Patients less likely to have postoperative improvement of visual acuity were those with longer than 6-month duration of visual symptoms (P = 0.024*) as well as patients with the presence of a relative afferent pupillary defect (RAPD) (P = 0.023*). The EEA can achieve good visual outcomes in patients harboring suprasellar meningiomas. Symptom duration of less than 6 months and lack of a RAPD were positive predictors of postoperative visual acuity.

Summary All-optical physiology (AOP) manipulates and reports neuronal activities with light, allowing for interrogation of neuronal functional connections with high spatiotemporal resolution. However, contemporary high-speed AOP platforms are limited to single-depth or discrete multi-plane recordings that are not suitable for studying functional connections among densely packed small neurons, such as neurons in Drosophila brains. Here, we constructed a 3D AOP platform by incorporating single-photon point stimulation and two-photon high-speed volumetric recordings with a tunable acoustic gradient-index (TAG) lens. We demonstrated the platform effectiveness by studying the anterior visual pathway (AVP) of Drosophila. We achieved functional observation of spatiotemporal coding and the strengths of calcium-sensitive connections between anterior optic tubercle (AOTU) sub-compartments and >70 tightly assembled 2-μm bulb (BU) microglomeruli in 3D coordinates with a single trial. Our work aids the establishment of in vivo 3D functional connectomes in neuron-dense brain areas., Graphical Abstract, Highlights • All-optical volumetric physiology = precise stimulation + fast volumetric recording • Precise single-photon point stimulation among genetically defined neurons • 3D two-photon imaging by an acoustic gradient-index lens for dense neural structures • Observation of 3D functional connectivity in Drosophila anterior visual pathway, Neuroscience; Techniques in Neuroscience; Biological Sciences Research Methodologies; Biological Sciences Tools

Introducción: Los meningiomas de la vaina del nervio óptico (MVNO) son tumores inusuales de la vía visual anterior. Sin tratamiento, el crecimiento del tumor lleva a pérdida visual progresiva hasta la ceguera debido a la compresión que ejerce sobre el nervio óptico. Presentación del caso: Paciente, sexo femenino, 42 años, sin antecedentes mórbidos, que en 1992, inicia cuadro de disminución de la agudeza visual del ojo izquierdo. La resonancia magnética (RM) cerebral informa una lesión expansiva fusiforme en relación a la vaina del nervio óptico izquierdo que lo engloba, altamente sugerente de MVNO. En esa ocasión se realiza exploración de órbita la cual resulta frustra, por lo que se decide observación con controles clínicos e imagenológicos anuales, permaneciendo estable. Aproximadamente diez años más tarde, en el lapso de un año, inicia agravación progresiva de la agudeza y campo visual, ptosis palpebral y alteraciones de la oculo-motilidad del ojo izquierdo, objetivadas por examen neuro-oftalmológico, por lo que se sospecha progresión de MVNO. Se solicita nueva RM que confirma crecimiento significativo del tumor. Se descarta nuevo abordaje quirúrgico por riesgo de mayor deterioro visual y se efectúa radioterapia conformacional con una dosis de 54 Gy. Actualmente, a la edad de 65 años, se cumplen 24 años de evolución, 13 post radioterapia, confirmándose estabilidad clínica y radiológica de MVNO. Discusión: La radioterapia, cuando se observaprogresión de la enfermedad, ha demostrado ser una terapia eficaz para los MVNO, con menos complicaciones y con mejores resultados en la preservación de la función visual a largo plazo.

Background and purpose Pediatric-onset multiple sclerosis (POMS) is associated with focal inflammatory lesions and the loss of cortical and deep gray matter. Optic neuritis (ON) and white matter (WM) lesions in the visual pathway can directly contribute to visual cortical mantle thinning. We determine the relative contributions of MS insult on anterior and posterior visual pathway integrity. Methods High- and low-contrast visual acuity, optical coherence tomography (OCT), and 3T MRI scans were obtained from 20 POMS patients (10 with remote ON) and 22 age- and sex-matched healthy controls. Cortical mantle thickness was measured using FreeSurfer. Fractional anisotropy (FA) and mean diffusivity were calculated for postchiasmal optic radiations (with and without WM lesions). Groups were compared using Student's t-test (adjusted for multiple comparisons), and simple linear regression was used to investigate interrelationships between measures. Results Mean cortical thickness of the whole brain was reduced in patients (2.49 mm) versus controls (2.58 mm, P = .0432) and in the visual cortex (2.07 mm vs. 2.17 mm, P = .0059), although the foveal confluence was spared. Mean FA of the optic radiations was reduced in POMS (.40) versus controls (.43, P = .0042) and correlated with visual cortical mantle thickness in POMS (P = .017). Visual acuity, OCT measures, and lesion volumes in the optic radiations were not associated with cortical mantle thickness. Conclusions POMS negatively impacts the integrity of the anterior visual pathway, but it is the loss of WM integrity that drives anterograde loss of the cortical mantle. Preserved visual acuity and foveal sparing imply some degree of functional and structural resilience.

To assess differential patterns of axonal loss and demyelination in the optic nerve in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD).Cross-sectional study.One hundred ninety-two participants, including 136 MS patients (272 eyes), 19 NMOSD patients (38 eyes), and 37 healthy control participants (74 eyes).All participants underwent spectral-domain OCT scans and multifocal visual evoked potential (mfVEP) recordings. High-resolution magnetic resonance imaging (MRI) with the diffusion protocol also was performed in all patients.Ganglion cell-inner plexiform layer (GCIPL) thickness and mfVEP amplitude and latency at 5 eccentricities; global and temporal retinal nerve fiber layer thickness.In optic neuritis (ON) eyes, the NMOSD patients had more severe GCIPL loss (P0.001) and mfVEP amplitude reduction (P0.001) compared with MS patients, whereas in contrast, mfVEP latency delay was more evident in MS patients (P0.001). The NMOSD patients showed more morphologic and functional loss at the foveal to parafoveal region, whereas the MS patients showed evenly distributed damage at the macula. Correlation analysis demonstrated a strong structure-function (OCT-mfVEP) association in the NMOSD patients, which was only moderate in the MS patients. In non-ON (NON) eyes, the MS patients showed significantly thinner GCIPL than controls (P0.001), whereas no GCIPL loss was observed in NON eyes in NMOSD. In addition, a significant correlation was found between all OCT and mfVEP measures in MS patients, but not in NMOSD patients. MRI demonstrated significant lesional load in the optic radiation in MS compared to NMOSD eyes (P = 0.002), which was related to the above OCT and mfVEP changes in NON eyes.Our study demonstrated different patterns of ON damage in NMOSD and MS. In MS, the ON damage was less severe, with demyelination as the main pathologic component, whereas in NMOSD, axonal loss was more severe compared with myelin loss. The disproportional mfVEP amplitude and latency changes suggested predominant axonal damage within the anterior visual pathway as the main clinical feature of NMOSD, in contrast to MS, where demyelination spreads along the entire visual pathway.

Acute idiopathic demyelinating optic neuritis is frequently the initial manifestation of multiple sclerosis (MS). We aimed to discuss the value of color vision testing to detect possible optic nerve involvement in patients with MS who had no history of optic neuritis. We evaluated color vision with Farnsworth-Munsell 100 (FM-100) hue test. Total error scores (TES), partial error scores for the red-green axis (RGS) and blue-yellow axis (BYS) were calculated. Topographic optic disc parameters (RNFL, RA, DA, CV, RV, and vertical C/D ratio), total macular volume (TMV), central macular thickness (CMT), and retinal ganglion cell layer (RGCL) were determined using spectral domain optical coherence tomography (SD-OCT). Choroidal thickness (CT) was measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Pattern visual evoked potentials (PVEP) were also performed. Twenty-eight patients with RRMS (56 eyes) and 25 healthy controls (50 eyes) were included. P100 latencies were significantly delayed and P100 amplitudes were significantly reduced in the patient group compared with the controls (p ≤ 0.05). Statistically significant thinning was found in temporal quadrant in the patient group compared with the controls (p = 0.002). TES RGS, and BYS were all increased in the patient group but this was not statistically significant. We found no correlation between TES, RGS, BYS, and P100 latencies or OCT parameters. In our investigation as to whether color vision testing could be a simple biomarker for showing neurodegeneration of the anterior visual pathway regardless of optic neuritis, PVEP and OCT-assessed RNFL thickness seemed to be a more valuable biomarker than color vision testing.

Visual field (VF) testing is an essential component of the neurological examination. The differential diagnosis of VF defects depends on relating this measure of afferent visual function to the structure of the visual pathway and optical coherence tomography (OCT) is an invaluable tool for detailed structural evaluation of the optic nerve and retina. This review describes the ways in which interpretation of VF and OCT can be used together to increase the accuracy of the localization of lesions along the visual pathway. Lesions of the anterior visual pathway (originating in ganglion cells or nerve fibre layer of the retina or optic nerve) will typically produce defects that respect the horizontal midline, reflecting the arcuate path of the ganglion cell axons as they travel to the optic nerve. OCT of peripapillary retinal nerve fibre layer and ganglion cell complex (GCC) will typically demonstrate irreversible thinning in compressive and demyelinating lesions affecting anterior visual pathway. Chiasmal lesions produce highly localizable VF defects (junctional scotoma and bitemporal hemianopia) which correspond to the thinning of nasal portion of GCC. Lesions of the optic tract result in incongruous homonymous hemianopia on VF with corresponding hemianopic thinning on GCC developing within months. Lesions affecting optic radiations usually produce more congruous homonymous VF defects and can also produce homonymous thinning on GCC, however, this takes much longer to develop as trans-synaptic degeneration at the lateral geniculate body must occur.

AIM To characterize the neuro-ophthalmological phenotype of cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) and assess visual acuity as a reproducible, quantitative outcome measure. METHOD We retrospectively analyzed clinical data from patients with CDD. Complete neuro-ophthalmological assessments, including visual acuity, were evaluated. RESULTS Of 26 patients (22 females, four males; median age 4y, interquartile range 2y 1mo-7y 10mo), cerebral visual impairment (CVI), defined as visual dysfunction in the absence of ocular or anterior visual pathway abnormalities, was diagnosed in all those over 2 years of age. Ophthalmological examinations revealed nystagmus in 10 patients and strabismus in 24 patients. Visual acuity was measured in 24 patients, by preferential looking in all and by sweep visual evoked potential in 13. Visual acuities were lower than age expectations and demonstrated improvement in the first 3 years. Adjusting for age and sex, average preferential looking visual acuity after 2 years of age was higher in patients with intact mobility than in those who were non-mobile. INTERPRETATION CVI was observed in patients with CDD. Visual acuity improved over time and correlated with mobility. Visual acuity, as a quantifiable measure of visual function, should be considered as an outcome measure in pre-clinical and clinical studies for CDD. What this paper adds Cerebral visual impairment is highly prevalent in cyclin-dependent kinase-like 5 deficiency disorder (CDD). Visual acuity is a measurable quantitative outcome measure in CDD. Visual acuity in CDD correlates with gross motor ability.

Measurement of retinal ganglion cell layer thickness by optical coherence tomography provides an objective and reliable evaluation of anterior visual pathway lesions to complement visual field testing in the management of optic chiasm compression from pituitary tumors.1,2 We demonstrated 3 differing patterns of ganglion cell layer thinning—junctional (figure 1, A and D), binasal (figure 1, B and E), and homonymous (figure 1, C and F)—and illustrated how these patterns correspond to the location of chiasmal compression by pituitary adenomas, anteriorly (figure 2A), centrally (figure 2B), or posteriorly (figure 2C). Consideration of the pattern of ganglion cell layer thinning in conjunction with visual field testing is useful for predicting the location of anterior visual pathway lesions.

Introduction: Optic atrophy results from the disease process that cause irreversible damage to the ganglion cells and the anterior visual pathway, but may also result from posterior visual pathway involvement. The etiology causing this condition is vast and regardless of underlying cause it carries bad visual prognosis and at times may be life threatening. The study aims to assess patients with optic nerve atrophy presenting to B.P. Koirala lions centre for ophthalmic studies and identify the underlying etiology. Materials and methods: This is a descriptive study conducted at B.P. Koirala Lions Centre for Ophthalmic studies. All cases of optic atrophy who presented to our outpatient department from March 2016 to March 2017 were included in the study. In addition to detailed evaluation, assessment of visual acuity, color vision, contrast sensitivity and visual field were done if feasible. Other relevant investigations were conducted to establish the underlying etiological cause. Results: A total of 62 patients were included in the study, with 35 patients having bilateral disease and 27 having unilateral disease accounting for 97 eyes with optic atrophy. The mean age of the affected was 40.63±17.36 years with male to female ratio of 1.2:1. The most common etiology for optic atrophy was traumatic neuropathy (n=16, 25.8%). Majority of eyes had pale disc (n=70, 72.2%) and the rest had temporal pallor (n=27, 27.8%). Conclusion: Traumatic optic neuropathy was the most common etiological cause of optic nerve atrophy.

Many insects use patterns of polarized light in the sky to orient and navigate. Here, we functionally characterize neural circuitry in the fruit fly, Drosophila melanogaster, that conveys polarized light signals from the eye to the central complex, a brain region essential for the fly’s sense of direction. Neurons tuned to the angle of polarization of ultraviolet light are found throughout the anterior visual pathway, connecting the optic lobes with the central complex via the anterior optic tubercle and bulb, in a homologous organization to the ‘sky compass’ pathways described in other insects. We detail how a consistent, map-like organization of neural tunings in the peripheral visual system is transformed into a reduced representation suited to flexible processing in the central brain. This study identifies computational motifs of the transformation, enabling mechanistic comparisons of multisensory integration and central processing for navigation in the brains of insects.

Background Although rare, cavernous malformations (CMs) of the optic nerve and anterior optic pathway (optic pathway cavernous malformations [OPCMs]) can occur, as described in several single case reports in the literature. Objective To describe the technical aspects of microsurgical management of CMs of the optic pathway on the basis of an extensive single-center experience and review of the literature. Methods A systematic literature review was performed to augment an earlier review, using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In addition, an institutional database was searched for all patients undergoing surgical resection of OPCMs. Patient information, surgical technique, and clinical and radiographic outcomes were assessed. Results Since the previous report, 14 CMs were resected at this institution or by the senior author at another institution. In addition, 34 cases were identified in the literature since the systematic review in 2015, including some earlier cases that were not discussed in the previous report. Most OPCMs were resected via pterional, orbital-pterional, and orbitozygomatic craniotomies. Visual outcomes were similar to those in earlier reports, with 70% of patients reporting stable to normal vision postoperatively. Conclusion OPCMs can occur throughout the anterior visual pathway and may cause significant symptoms. Surgery is feasible and should be considered for OPCMs presenting to a surface of the nerve. Favorable results can be obtained with resection, although optimal results are obtained with patients who present with milder symptoms without longstanding damage to the optic apparatus.

In early (EB) and late blind (LB) children, vision deprivation produces cross-modal plasticity in the visual cortex. The progression of structural- and tract-based spatial statistics changes in the visual cortex in EB and LB, as well as their impact on global cognition, have yet to be investigated. The purpose of this study was to determine the cortical thickness (CT), gyrification index (GI), and white matter (WM) integrity in EB and LB children, as well as their association to the duration of blindness and education. Structural and diffusion tensor imaging data were acquired in a 3T magnetic resonance imaging in EB and LB children (n = 40 each) and 30 sighted controls (SCs) and processed using CAT12 toolbox and FSL software. Two sample t-test was used for group analyses with P

Purpose of review Optic nerve sheath meningiomas (ONSMs) are rare benign tumors of the anterior visual pathway which present with slowly progressive and painless vision loss and account for approximately 2% of all orbital tumors. This article provides an overview as well as an update on the ONSMs with regards to cause, epidemiology, clinical presentation, diagnosis, and management in adults and pediatric population. Recent findings The clinical presentation and prognosis of ONSMs can vary and largely depend on the location of tumor as well as the histologic type. Overall, the diagnosis is based on clinical presentation, examination, and neuroimaging findings. Nevertheless, delays in diagnosis or misdiagnosis are not uncommon and can result in higher morbidity rates. Recent advances in diagnostic as well as more effective and less-invasive treatment options are discussed in this review. Summary ONSMs are a rare cause of slowly progressive and inexorable visual loss. Although ONSM diagnosis depends on the characteristic clinical and radiologic findings, prompt diagnosis, and appropriate management is critical for favorable visual outcomes. Thus, current focus is optimizing diagnostic as well-treatment methods for patients with ONSMs.

SUMMARYMany insects use patterns of polarized light in the sky to orient and navigate. Here we functionally characterize neural circuitry in the fruit fly,Drosophila melanogaster, that conveys polarized light signals from the eye to the central complex, a brain region essential for the fly’s sense of direction. Neurons tuned to the angle of polarization of ultraviolet light are found throughout the anterior visual pathway, connecting the optic lobes with the central complex via the anterior optic tubercle and bulb, in a homologous organization to the ‘sky compass’ pathways described in other insects. We detail how a consistent, map-like organization of neural tunings in the peripheral visual system is transformed into a reduced representation suited to flexible processing in the central brain. This study identifies computational motifs of the transformation, enabling mechanistic comparisons of multisensory integration and central processing for navigation in the brains of insects.

BACKGROUND AND PURPOSE: Demyelinating lesions in the anterior visual pathways represent an underestimated marker of disease dissemination in patients with MS. We prospectively investigated whether a dedicated high-resolution MR imaging technique, the 3D-T2-STIR-ZOOMit, improves demyelinating lesion detection compared with the current clinical standard sequence, the 2D-T2-STIR. MATERIALS AND METHODS: 3T MR imaging of the anterior visual pathways (optic nerves, chiasm, and tracts) was performed using 3D-T2-STIR-ZOOMit and 2D-T2-STIR, in patients with MS and healthy controls. Two experienced neuroradiologists assessed, independently, demyelinating lesions using both sequences separately. 3D-T2-STIR-ZOOMit scan-rescan reproducibility was tested in 12 patients. The Cohen κ was used for interrater agreement, and the intraclass correlation coefficient for reproducibility. Between-sequence detection differences and the effects of location and previous acute optic neuritis were assessed using a binomial mixed-effects model. RESULTS: Forty-eight patients with MS with (n = 19) or without (n = 29) past optic neuritis and 19 healthy controls were evaluated. Readers' agreement was strong (3D-T2-STIR-ZOOMit: 0.85; 2D-T2-STIR: 0.90). The 3D-T2-STIR-ZOOMit scan-rescan intraclass correlation coefficient was 0.97 (95% CI, 0.96–0.98; P < .001), indicating excellent reproducibility. Overall, 3D-T2-STIR-ZOOMit detected more than twice the demyelinating lesions (n = 89) than 2D-T2-STIR (n = 43) (OR = 2.7; 95% CI, 1.7–4.1; P < .001). In the intracranial anterior visual pathway segments, 33 of the 36 demyelinating lesions (91.7%) detected by 3D-T2-STIR-ZOOMit were not disclosed by 2D-T2-STIR. 3D-T2-STIR-ZOOMit increased detection of demyelinating lesion probability by 1.8-fold in patients with past optic neuritis (OR = 1.8; 95% CI, 1.2–3.1; P = .01) and 5.9-fold in patients without past optic neuritis (OR = 5.9; 95% CI, 2.5–13.8; P < .001). No false-positive demyelinating lesions were detected in healthy controls. CONCLUSIONS: Dedicated 3D-T2-STIR-ZOOMit images improved substantially the detection of MS disease dissemination in the anterior visual pathways, particularly in the intracranial segments and in patients without past optic neuritis.

Purpose: to describe a patient with visual field (VF) defect from an occipital lobe lesion that was found to have macular ganglion cells complex (GCC) quadrantic reduction without significant peripapillary retinal nerve fiber layer (RNFL) loss on optical coherence tomography (OCT). To emphasize that macular GCC loss may be the major ocular manifestation of trans-synaptic optic pathway degeneration in occipital lobe lesions. Observations: A 15-year-old female was investigated after a VF examination revealed a right homonymous inferior quadrantanopia. Fundoscopic examination was completely normal as were the peripapillary retinal nerve fiber layer (RNFL) thickness measurements on OCT. Macular thickness measurements however, revealed superior homonymous quadrantic GCL reduction evidencing retinal neuronal loss in direct correspondence with her VF defect. Magnetic resonance imaging showed a localized left occipital lobe gliotic lesion as the explanation for her VF defect. Conclusions and Importance: Small post-geniculate optic pathway lesions may lead to retrograde trans-synaptic degeneration that can be detected on OCT-measured macular GCL measurements despite normal peripapillary RNFL estimates. Awareness of such occurrence in important to avoid diagnostic confusion with other anterior visual pathway diseases. Keywords: Optical coherence tomography, Retinal ganglion cells layer, Occipital lesions, Retrograde trans-synaptic degeneration

Jana Lizrova Preiningerova,1 Anna Grishko,2 Lukas Sobisek,2 Michaela Andelova,1 Barbora Benova,1 Karolina Kucerova,1 Eva Kubala Havrdova1 1Center of Clinical Neuroscience, Department of Neurology, General University Hospital, 1st Faculty of Medicine, Charles University, Prague Czech Republic; 2Department of Statistics and Probability, University of Economics, Prague, Czech Republic Purpose: Anterior visual pathway reflects axonal loss caused by both optic neuritis (ON) and neurodegeneration in multiple sclerosis (MS). Although the axonal injury post-ON is thought to be complete by 6 months of onset, most studies using optical coherence tomography (OCT) to evaluate retinal changes as a marker of neurodegeneration exclude eyes with a history of ON or consider them separately. The objective of this study was to assess whether the eyes post-ON (>6 months) show in later years different rate of chronic retinal changes than the fellow eyes not affected by ON. Patients and methods: Fifty-six patients with MS with a history of ON in one eye (ON eyes) and no ON in the fellow (FL) eye, who were followed by OCT for>2 years, were selected from a cohort of patients with MS. Paired eye analysis was performed. Results: Mean interval post-ON at baseline was 5.65 (SD 5.05) years. Mean length of follow-up by OCT was 4.57 years. There was no statistical difference in absolute or relative thinning of retinal nerve fiber layer in peripapillary area between the ON and FL eyes. Conclusion: This study has shown that we do not need to exclude eyes with a history of ON from longitudinal studies of neurodegeneration in MS, provided that we use data outside of the frame of acute changes post-ON. Long-term changes of peripapillary retinal nerve fiber layer in ON and FL eyes are equal. Keywords: optical coherence tomography, neurodegeneration, multiple sclerosis, retina

Optic nerve sheath meningiomas (ONSM) are rare, slow-growing, benign tumours, which constitute approximately 2% of all orbital tumours of the anterior visual pathway (or orbital or anterior visual pathway) and 1–2% of all meningiomas. Middle-aged females are primarily affected. Untreated ONSMs usually lead to progressive visual decline, colour blindness, and finally complete loss of vision. Surgical excision may result in blindness in the affected eye. Stereotactic fractionated radiotherapy has recently shown effectiveness in improving or stabilising remaining visual function with minimal procedural morbidity in patients with ONSM. We present a case of a 59-year-old female with unilateral optic nerve sheath meningioma treated with stereotactic fractionated radiotherapy. During eight months of follow-up we observed persistent oedema of the right optic disc and full visual acuity. Optical coherence tomography showed decreased peripapillary nerve fibre layer.

The anterior visual pathway (AVP) conducts visual information from the medulla of the optic lobe via the anterior optic tubercle (AOTU) and bulb (BU) to the ellipsoid body (EB) of the central complex. The anatomically defined neuron classes connecting the AOTU, BU, and EB represent discrete lineages, genetically and developmentally specified sets of cells derived from common progenitors (Omoto et al., Current Biology, 27, 1098-1110, 2017). In this article, we have analyzed the formation of the AVP from early larval to adult stages. The immature fiber tracts of the AVP, formed by secondary neurons of lineages DALcl1/2 and DALv2, assemble into structurally distinct primordia of the AOTU, BU, and EB within the late larval brain. During the early pupal period (P6-P48) these primordia grow in size and differentiate into the definitive subcompartments of the AOTU, BU, and EB. The primordium of the EB has a complex composition. DALv2 neurons form the anterior EB primordium, which starts out as a bilateral structure, then crosses the midline between P6 and P12, and subsequently bends to adopt the ring shape of the mature EB. Columnar neurons of the central complex, generated by the type II lineages DM1-4, form the posterior EB primordium. Starting out as an integral part of the fan-shaped body primordium, the posterior EB primordium moves forward and merges with the anterior EB primordium. We document the extension of neuropil glia around the nascent EB and BU, and analyze the relationship of primary and secondary neurons of the AVP lineages.

Objective: This study aims to investigate whether bidirectional degeneration occurs within the visual pathway and, if so, the extent of such changes in neuromyelitis optica spectrum disorder (NMOSD). Methods: In total, 36 NMOSD and 24 healthy controls (HCs) were enrolled. Three-dimensional T1-weighted magnetic resonance imaging (MRI) and diffusion tensor imaging were used to analyze damage to the posterior visual pathway. Damage to the anterior visual pathway was measured by optical coherence tomography. Results: In total, 24 NMOSD with prior optic neuritis (NMOON) patients showed significant reduction of peripapillary retinal nerve fiber layer, inner and outer retinal thickness, lateral geniculate nucleus volume, primary visual cortex volume, and decreased integrity of optic radiations, compared with 12 NMOSD without prior optic neuritis (NMONON) patients and 24 HCs. In NMONON, only the inner retinal thickness and the integrity of optic radiations were significantly reduced in comparison with HCs. Moreover, patients with optic neuritis showed severe bidirectional degeneration, the loss of the RNFL was greater than the atrophy of V1. Conclusion: Our study indicated the presence of trans-synaptic degeneration in NMOSD. Damage to the inner retina and optic radiations can be observed even in NMONON. After an episode of optic neuritis, the anterior visual pathway damage is greater than the posterior visual pathway damage.

The afferent visual pathway represents the most frequently affected white matter pathway in multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD). Diffusion tensor imaging (DTI) can reveal microstructural or non-overt brain tissue damage and quantify pathological processes. DTI facilitates the reconstruction of major white matter fiber tracts allowing for the assessment of structure-function and damage-dysfunction relationships. In this review, we outline DTI studies investigating the afferent visual pathway in idiopathic optic neuritis (ON), NMOSD, and MS. Since MS damage patterns are believed to depend on multiple factors, i.e., ON (anterior visual pathway damage), inflammatory lesions (posterior visual pathway damage), and global diffuse inflammatory and neurodegenerative processes, comprehensive knowledge on different contributing factors using DTI in vivo may advance our understanding of MS disease pathology. Combination of DTI measures and visual outcome parameters yields the potential to improve routine clinical diagnostic procedures and may further the accuracy of individual prognosis with regard to visual function and personalized disease outcome. However, due to the inherent limitations of DTI acquisition and post-processing techniques and the so far heterogeneous and equivocal data of previous studies, evaluation of the true potential of DTI as a possible biomarker for afferent visual pathway dysfunction is still substantially limited. Further research efforts with larger longitudinal studies and standardized DTI acquisition and post-processing validation criteria are needed to overcome current DTI limitations. DTI evaluation at different levels of the visual pathway has the potential to provide markers for individual damage evaluation in the future. As an imaging biomarker, DTI may support individual outcome prediction during personalized treatment algorithms in MS and other neuroinflammatory diseases, hereby leveraging the concept of predictive, preventive, and personalized medicine in the field of clinical neuroimmunology.

Aneurysmal volume expansion after endovascular treatment is caused by intra-aneurysmal thrombosis in the early postembolization period. Although postembolization mass effect on cranial nerves and other adjacent structures has been previously reported, we are unaware of reports involving the anterior visual pathway. A 66-year-old woman with a 2-week history of blurred vision without headache was found to have a large, unruptured anterior communicating artery aneurysm. One month after endovascular treatment of the aneurysm with coiling and flow diversion, the patient developed decreased vision in her right eye and a left homonymous hemianopia. Magnetic resonance imaging demonstrated compression of the right optic nerve, chiasm, and edema of the right optic tract. The patient was treated with a course of high dose corticosteroids, and over the course of several weeks, her vision improved and the optic tract edema resolved. We alert clinicians to this rare but potentially reversible visual complication of endovascular treatment of intracranial aneurysms.

The Drosophila central brain consists of stereotyped neural lineages, developmental-structural units of macrocircuitry formed by the sibling neurons of single progenitors called neuroblasts. We demonstrate that the lineage principle guides the connectivity and function of neurons, providing input to the central complex, a collection of neuropil compartments important for visually guided behaviors. One of these compartments is the ellipsoid body (EB), a structure formed largely by the axons of ring (R) neurons, all of which are generated by a single lineage, DALv2. Two further lineages, DALcl1 and DALcl2, produce neurons that connect the anterior optic tubercle, a central brain visual center, with R neurons. Finally, DALcl1/2 receive input from visual projection neurons of the optic lobe medulla, completing a three-legged circuit that we call the anterior visual pathway (AVP). The AVP bears a fundamental resemblance to the sky-compass pathway, a visual navigation circuit described in other insects. Neuroanatomical analysis and two-photon calcium imaging demonstrate that DALcl1 and DALcl2 form two parallel channels, establishing connections with R neurons located in the peripheral and central domains of the EB, respectively. Although neurons of both lineages preferentially respond to bright objects, DALcl1 neurons have small ipsilateral, retinotopically ordered receptive fields, whereas DALcl2 neurons share a large excitatory receptive field in the contralateral hemifield. DALcl2 neurons become inhibited when the object enters the ipsilateral hemifield and display an additional excitation after the object leaves the field of view. Thus, the spatial position of a bright feature, such as a celestial body, may be encoded within this pathway.