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Our recent report demonstrated that hesperetin (Hst) as a citrus flavonoid, significantly reduces the levels of demyelination in optic chiasm of rats. Previous evidence also indicated that nano-hesperetin (nano-Hst) possesses beneficial impacts in experimental models of Alzheimer's disease and autism. In this study, the effects of nano-Hst on latency of visual signals, demyelination levels, glial activation, and expression of Olig2 and MBP were evaluated in lysolecithin (LPC)-induced demyelination model. Focal demyelination was induced by injection of LPC (1%, 2 μL) into the rat optic chiasm. Animals received oral administration of nano-Hst at dose of 20 mg/kg for 14 or 21 days post LPC injection. Visual evoked potential (VEP) recording showed that nano-Hst reduces the latency of visual signals and ameliorates the extent of demyelination areas and glial activation. Expression levels of the Olig2 and MBP were also significantly increased in nano-Hst treated rats. Overall, our data suggest that nano-Hst reduces the latency of visual signals through its protective effects on myelin sheath, amelioration of glial activation, and enhancement of endogenous remyelination., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Compression of the optic chiasm causes an optic neuropathy that may be associated with reversible visual loss often immediately following surgical decompression. While the precise pathogenesis of retinal ganglion cell impairment and eventual death remains poorly understood, a number of putative mechanisms may play a role. In this article we review the evidence supporting various stages of visual loss and recovery in chiasmal compression. These include conduction block, demyelination, ischemic insult, and retrograde and anterograde degeneration. We also describe novel advances in magnetic resonance imaging with specialized modalities such as diffusion tensor imaging have provided further information to explain the underlying mechanism of visual loss. Functional measures including electrophysiology are time-consuming but have shown moderate prognostic ability. Optical coherence tomography has provided novel new biomarkers for predicting outcome following surgical decompression. Both retinal nerve fiber layer thickness and ganglion cell complex thicknesses have shown to have excellent predictive power. Such advances serve to inform patients and clinicians of pre-operative factors that predict the extent of visual recovery following medical or surgical treatment of para-chiasmal lesions., (Copyright © 2019. Published by Elsevier Ltd.)

Purpose of Review: This article reviews the anatomy, symptoms, examination findings, and causes of diseases affecting the optic chiasm, optic tracts, optic radiations, and occipital lobes., Recent Findings: Modern ophthalmic imaging can be used to monitor the effects of diseases of the optic chiasm and tract on the retinal ganglion cells. It can also be used to visualize transsynaptic degeneration of the anterior visual pathway in the setting of acquired retrogeniculate lesions. Visual prostheses that directly stimulate the occipital lobe are a potential strategy for rehabilitation that is in active clinical trials., Summary: Detecting and characterizing visual deficits due to optic chiasm and retrochiasmal disease are important for the diagnosis, localization, and monitoring of neurologic disease; identifying patient disability; and guiding rehabilitation.

The case concerns a 55 year-old female patient with progressive visual decrease in her right eye that showed a junctional scotoma in the visual field study. A magnetic resonance scan was performed, which showed a right middle cerebral artery aneurysm with ipsolateral chiasmatic involvement., (Copyright © 2019 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.)

Background and Objective: Large suprasellar tumors often compress the optic chiasm and give rise to visual impairment. Most patients have significantly improved visual function at 1 to 4 months after chiasmal decompression surgery, and only a few individuals regain normal vision at 1 week after surgery. How the recovery of visual function in these patients affects the visual cortex is not fully understood. In this study, we aimed to investigate alterations in brain functional connectivity (FC) in suprasellar tumor patients with visual improvement using resting-state functional magnetic resonance imaging (rs-fMRI). Methods: This longitudinal study was conducted on 13 suprasellar tumor patients who had ophthalmological examinations and rs-fMRI at the following time points: within 1-week preoperation (Pre-op), 1-week postoperation (Post-1w) and 1-month postoperation (Post-1m). The visual impairment score (VIS), local functional correlation (LCOR) and FC values were subjected to one-way ANOVA. Pearson correlation coefficients between changes in the LCOR and clinical factors were calculated. Results: The VIS was significantly decreased at both Post-1w and Post-1m compared to that at Pre-op. Whole-brain analysis of LCOR values showed that the left V1 (primary occipital cortex) was increased significantly at Post-1m compared to that at Pre-op (p < 0.05, FDR corrected). ROI analysis exhibited a significant negative correlation between the LCOR and VIS changes at Post-1m compared to those at Pre-op (p < 0.05, r = - 0.60). FC analysis within the visual network showed that the FC strengths were significantly increased between the left V5 and the left V4, right V3a, left V3, left V2d, and right V5 at Post-1m compared to those at Pre-op (p < 0.05, FDR corrected). Additionally, the FC strengths were significantly increased between the left V5 and the left V1, right orbital-frontal gyrus and left posterior supramarginal gyrus at the whole-brain network level at Post-1m compared to those at Pre-op (p < 0.05, FDR corrected). Conclusions: Postoperative visual improvement can be reflected by the increased FC of the visual cortex at Post-1w and Post-1m, especially at Post-1m. The LCOR value of the left V1 was associated with improved visual outcomes and may be used to objectively assess early visual recovery after chiasmal decompression at Post-1m., Competing Interests: Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© The author(s).)

Background: Patients with visual loss from macroadenomas compressing their optic apparatus may also have concomitant age-related visual pathology such as cataracts. How these two pathologies interact with each other is not well documented., Objective: The interaction between these two pathologies in elderly patients is the subject of this study., Methods: We identified a series of non-functioning macroadenoma patients over age 50 years with tumors compressing the chiasm who underwent transsphenoidal surgery at our institution between 2004 and 2018. Pre- and post-operative visual complaints, tumor size and extent of resection were analyzed. Prevalence of the diagnosis of cataract and prevalence of cataract surgery in each decade were compared with national averages., Results: We identified 200 patients who met selection criteria. 18% of these patients had a diagnosis of cataract and 12.5% had cataract surgery. Compared with the Eye Diseases Prevalence Research Group (EDPRG) study, the prevalence of cataract surgery was 2.5 times the national average of 5.1%. 32% of these patients had no improvement in their vision after cataract surgery but 76% improved after transsphenoidal surgery., Conclusions: We reported a high prevalence of cataract surgery in patients over age 50 in patients with pituitary macroadenomas compressing the optic pathway compared with national averages in patients without adenomas. While visual loss from adenoma likely precipitated more cataract surgeries in this group of patients, some who may not have required it, those patients with cataracts who did not have their cataracts extracted were less likely to recover vision after transsphenoidal surgery. Addressing both pathologies is beneficial.

Due to an increased crossing of the optic nerve fibers at the optic chiasm in albinism, the visual cortex receives largely monocular input from the contralateral eye. Here we investigated whether this obstruction of binocular integration at the cortical input stage also impacts on interocular information exchange at the high processing level of visual memory. Interocular transfer (IOT) of visual memory retrieval was tested psychophysically after monocular encoding in 8 albinotic participants and 24 healthy controls. The retrieval performance (hit rate, reaction time, d') was determined when using the same or different eye at encoding. To assess the effect of reduced visual acuity (VA) on recognition, we simulated interocular acuity differences (IOA) in two healthy control groups (each n = 8), i.e., with large (VA: 0.89 vs. 0.12) and small simulated interocular difference (VA: 0.25 vs. 0.12), with the latter matched to that observed in the albinotic participants (VA: 0.20 vs. 0.15). A significant decrease in retrieval performance was observed in controls with simulated strongly reduced VA in one eye (p < 0.0001). For the other conditions and groups, including the albinotic participants, no dependence on VA and no significant difference between using the same or different eye was observed. This indicates interocular transfer and hence interocular information exchange in human albinism. These findings thus provide insights into the scope of plasticity of binocular information processing and inter-hemispherical information flow., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Purpose: Chiasmapexy is a poorly described surgical procedure adopted to correct the downward displacement of suprasellar visual system (SVS) into an empty sella (ES) causing visual worsening. The aim of our study is to define the indications for extradural and intradural chiasmapexy., Methods: A systematic literature review has been performed on MEDLINE database (US National Library of Medicine), including only articles that depicted cases of surgically treated patients affected by ES and progressive delayed visual worsening. Moreover, we have reported three cases of secondary ES syndrome (SESS) with visual worsening treated in our Department with transsphenoidal (TS) microsurgical intradural approach. Finally, we have compared the results of extradural and intradural chiasmapexy described in literature., Results: The etiology of visual impairment is different in primary and secondary ESS. In primary ESS (PESS) the only predisposing factor is a dehiscence of diaphragma sellae, and the anatomical distortion caused by displacement of optic chiasm or traction of pituitary stalk and infundibulum may determine a direct injury of neural fibers and ischemic damage of SVS. In PESS the mechanical elevation of SVS performed through extradural approach is sufficient to resolve the main pathologic mechanism. In SESS, arachnoidal adhesions play an important role in addition to downward herniation of SVS. Consequently, the surgical technique should provide elevation of SVS combined to intradural release of scar tissue and arachnoidal adhesions. In treatment of SESS, the intradural approaches result to be more effective, guaranteeing the best visual outcomes with the lowest complications rates., Conclusions: The intradural chiasmapexy is indicated in treatment of SESS, instead the extradural approaches are suggested for surgical management of PESS.

Purpose: To verify whether multifocal visual evoked potential (mfVEP) can differentiate eyes with temporal hemianopia due to chiasmal compression from healthy controls. To assess the relationship between mfVEP, standard automated perimetry (SAP), and Fourier domain-optical coherence tomography (FD-OCT) macular and peripapillary retinal nerve fiber layer (RNFL) thickness measurements., Methods: Twenty-seven eyes with permanent temporal visual field (VF) defects from chiasmal compression on SAP and 43 eyes of healthy controls were submitted to mfVEP and FD-OCT scanning. Multifocal visual evoked potential was elicited using a stimulus pattern of 60 sectors and the responses were averaged for the four quadrants and two hemifields. Optical coherence tomography macular measurements were averaged in quadrants and halves, while peripapillary RNFL thickness was averaged in four sectors around the disc. Visual field loss was estimated in four quadrants and each half of the 24-2 strategy test points. Multifocal visual evoked potential measurements in the two groups were compared using generalized estimated equations, and the correlations between mfVEP, VF, and OCT findings were quantified., Results: Multifocal visual evoked potential-measured temporal P1 and N2 amplitudes were significantly smaller in patients than in controls. No significant difference in amplitude was observed for nasal parameters. A significant correlation was found between mfVEP amplitudes and temporal VF loss, and between mfVEP amplitudes and the corresponding OCT-measured macular and RNFL thickness parameters., Conclusions: Multifocal visual evoked potential amplitude parameters were able to differentiate eyes with temporal hemianopia from controls and were significantly correlated with VF and OCT findings, suggesting mfVEP is a useful tool for the detection of visual abnormalities in patients with chiasmal compression.

Multiple sclerosis (MS) is an autoimmune disease in which more than 70% of patients experience visual disturbance as the earliest symptoms. Lysolecithin (LPC)-induced focal demyelination model has been developed to evaluate the effects of different therapies on myelin repair improvement. In this study, the effects of pregabalin administration on myelin repair and glial activation were investigated. Local demyelination was induced by administration of LPC (1%, 2μL) into the rat optic chiasm. Rats underwent daily injection of pregabalin (30mg/kg, i.p) or vehicle. Visual-evoked potentials (VEPs) recordings were performed for evaluating the function of optic pathway on days 3, 7, 14 and 28 post lesions. Myelin specific staining and immunostaining against GFAP and Iba1 were also carried out for assessment of myelination and glial activation respectively. Electrophysiological data indicated that pregabalin administration could significantly reduce the P1-N1 latency and increase the amplitude of VEPs waves compared to saline group. Luxol fast blue staining and immunostaining against PLP, as mature myelin marker, showed that myelin repair was improved in animals received pregabalin treatment. In addition, pregabalin effectively reduced the expression of GFAP and Iba1 as activated glial markers in optic chiasm. The present study indicates that pregabalin administration enhances myelin repair and ameliorates glial activation of optic chiasm following local injection of LPC., (Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.)

Anomalies in the frontal lobe can interfere with visual function by compression of the optic chiasm and nerve. The gyrus rectus is located at the anterior cranial fossa floor superior to the intracranial optic nerves and chiasm. Compression of these structures by the gyrus rectus is often caused by neoplastic or dysplastic growth in the area. We report a rare case of a herniated gyrus rectus impinged on the optic chiasm and nerve without a clear pathological cause for the herniation., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Purpose: To demonstrate the utility of an uncrossed asymmetry in full-field pattern reversal visual evoked potentials (FF-PVEPs) will accurately predict a retrochiasmal lesion confirmed by MRI., Methods: During an 8-year period, 754 patients had FF-PVEPs performed and analyzed without knowledge of their clinical histories and imaging studies. Interhemispheric amplitude ratios were calculated between N75-P100 and P100-N145 and deemed significant if both demonstrated greater than 50% amplitude asymmetry no matter which eye was stimulated (uncrossed symmetry)., Results: We identified 11 patients of 754 patients evaluated for 8 years (1.5%) whose FF-PVEP fulfilled our amplitude criteria. Ten of 11 had retrochiasmal lesions confirmed with MRI for a calculated positive predictive value of 91%., Conclusions: These data provide initial support for the hypothesis that specified amplitude criteria in FF-PVEPs can provide evidence for a retrochiasmal lesion. An abnormal interhemispheric amplitude ratio in FF-PVEPs is underrecognized as a diagnostic criterion for retrochiasmal lesion prediction.

Purpose: The purpose of this study was to investigate correlations between retinal fiber thickness measured by optical coherence tomography (OCT) and anterograde functional and structural differences in the optic pathway of patients with compression of the optic chiasm. Our hypothesis was that loss of visual acuity caused by chronic compressive pathologies may lead to an irreversible decline in vision because of permanent neurodegeneration of the optic radiations and visual cortex., Methods: Quantitative OCT, functional magnetic resonance imaging (MRI) and diffusion tensor MRI measurements were made in 17 patients being surgically treated for chiasmal compression., Results: In our study we found that surgically irreversible visual field defects and reduced retinal nerve fiber layer thickness were significantly associated with lower fractional diffusion anisotropy and higher diffusivities in optic radiations and less functional MRI activation in the visual cortex., Conclusions: Damage to the retinal nerve fiber layer is associated with downstream structural and functional degradation of the optic pathway. This may be related to trans-synaptic degeneration and the fact that these factors are important potential imaging biomarkers for predicting visual recovery after surgical decompression.

Purpose: To evaluate the performance of macular ganglion cell-inner plexiform layer (mGCIPL) measurement with Cirrus high-definition (HD) optical coherence tomography (OCT) for early detection of optic chiasmal compression., Methods: Forty-six eyes of 46 patients with optic chiasmal compression caused by a pituitary adenoma (PA group), 31 eyes of 31 patients with normal tension glaucoma (NTG group), and 32 eyes of 32 normal participants (control group) were enrolled. The PA group was subdivided into two subgroups, which comprised patients with temporal visual field (VF) defects (perimetric PA group, 34 eyes) and without VF defect (preperimetric PA group, 12 eyes). The mGCIPL thickness and circumpapillary retinal nerve fiber layer (cpRNFL) thickness were measured using Cirrus HD-OCT. We calculated the number of patients who had an abnormal GCA sector map, defined as at least one yellow or red sector., Results: Eyes in the perimetric PA group had significantly decreased mGCIPL thickness in all sectors. Eyes in the preperimetric PA group had significantly thinner mGCIPL in the superior, superonasal, inferonasal, and inferior sectors than eyes in control group, but no changes in cpRNFL parameters were observed. The mGCIPL thickness in inferonasal area showed the greatest AUC value (0.965), followed by the superonasal area (0.958) for discriminating preperimetric PA group from the control group. A higher reduction rate of mGCIPL thickness was noted in the nasal sector compared to other sectors, which was irrespective of temporal visual field defects. The mGCIPL thickness maps showed superonasal (P = 0.003) and inferonasal thinning in the PA group (P = 0.003), while inferotemporal thinning was revealed in the NTG group (P = 0.001)., Conclusions: Macular GCIPL thickness parameters obtained with the Cirrus HD-OCT were useful in early detection of chiasmal compression and differentiating from NTG by characteristic nasal mGCIPL thinning.

In humans, the nasal retina projects to the contralateral hemisphere, whereas the temporal retina projects ipsilaterally. The nasotemporal line that divides the retina into crossed and uncrossed parts coincides with the vertical meridian through the fovea. This normal projection of the retina is severely altered in albinism, in which the nasotemporal line shifted into the temporal retina with temporal retinal fibers cross the midline at the optic chiasm. This study proposes the loss of binocular vision as direct cause for misrouting of temporal retinal fibers and shifting of the nasotemporal line temporally in albinism. It is supported by many observations that clearly indicate that loss of binocular vision causes uncrossed retinal fibers to cross the midline. This hypothesis may alert scientists and clinicians to find ways to prevent or minimize the loss of binocular vision that may occur in some diseases such as albinism and early squint. Hopefully, this will minimize the misrouting of temporal fibers and improve vision in such diseases., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The optic tract section at the optic chiasm is expected to disturb the suprachiasmatic nucleus (SCN) rhythm, circadian rhythm and melatonin secretion rhythms in humans, although detailed studies have never been conducted. The aim of this paper was to describe melatonin and cortisol profiles in patients with a pituitary tumor exerting optic chiasm compression. Six patients with pituitary tumors of different size, four of whom had significant optic chiasm compression, were examined. In each brain, MRI, an ophthalmological examination including the vision field and laboratory tests were performed. Melatonin and cortisol concentrations were measured at 22:00 h, 02:00 h, 06:00 h, and 10:00 h in patients lying in a dark, isolated room. One of the four cases with significant optic chiasm compression presented a flattened melatonin rhythm. The melatonin rhythm was also disturbed in one patient without optic chiasm compression. Larger tumors may play a role in the destruction of neurons connecting the retina with the suprachiasmatic nucleus (SCN) and breaking of basic way for inhibiting effect to the SCN from the retina., (Copyright © 2014 Polish Neurological Society. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.)

A 56-year-old man suffered a high velocity linear acceleration closed head injury, resulting in skull fractures including bone dehiscence at the planum sphenoidale and tuberculum sellae. After regaining consciousness, he reported blurry vision and episodic diplopia. Visual field testing showed a bitemporal hemianopia. Ocular motility testing uncovered no misalignment. Brain MRI revealed post-traumatic encephalomalacia within the optic chiasm, resulting in the visual field defect and subsequent hemifield slide. Normally, cerebral processing of overlap between the visual fields prevents hemifield slide, which is caused by episodic loss of visual field overlap with subsequent slipping or sliding apart of images., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Objective: Dopamine agonists (DA) are the treatment of choice in patients with macroprolactinomas. Brain and optic chiasm herniation are unusual complications following treatment with DA., Report: We present a case of a giant prolactinoma complicated by visual deterioration following cabergoline treatment. A 42-year-old man was admitted with seizures, right visual loss and visual defect in the upper left temporal quadrant. Magnetic resonance imaging (MRI) identified a giant adenoma, which proved to be a prolactinoma, compressing the optic chiasm and extending into the suprasellar region. Treatment with cabergoline was initiated resulting in improvement in visual fields, tumor shrinkage and prolactin level decrease. Five months later and despite tumor reduction, a deterioration of his visual fields was observed. The second MRI revealed brain and optic chiasmal herniation into the pituitary sella. Cabergoline dose was reduced and surgical resection of the adenoma along with untethering of the optic nerve was performed leading to improvement of the visual defects., Conclusions: This report describes a rare case of brain and optic chiasmal herniation attributed to DA therapy for a macroprolactinoma. It is important for clinicians to examine visual fields and promptly identify any visual deterioration in patients with macroprolactinomas receiving DA treatment.

Importance: Children with optic pathway gliomas (OPGs) frequently experience vision loss from their tumors. Standard front-line treatment using carboplatin-based chemotherapy typically produces only a modest benefit (eg, stabilization or 0.2 logMAR improvement) in visual acuity (VA). Bevacizumab is a monoclonal antibody that targets vascular endothelial growth factor and acts primarily as an anti-angiogenic agent. Recent reports suggest a qualitative improvement in vision after bevacizumab-based treatment in children with OPGs., Observations: We report 4 cases of pediatric OPGs (2 neurofibromatosis type 1-related and 2 sporadic cases) that received treatment with bevacizumab due to progressive VA or visual field (VF) loss despite prior treatment with chemotherapy or proton-beam radiation. All 4 subjects demonstrated a marked improvement in their VA, VF, or both while receiving bevacizumab-based therapy. Three patients had complete resolution of their VA or VF loss in at least 1 eye-2 of whom had previously received bevacizumab therapy., Conclusions and Relevance: Given that most patients with OPG-related visual impairment will show modest or no visual improvement with standard treatment, the incorporation of bevacizumab in these cases may greatly improve visual outcomes and should be considered in appropriate clinical situations.

Objective: To examine the anatomic features and function of the macula in achiasma and to compare visual acuity, eye movements, foveation, and eye velocity before and after tenotomy and reattachment (T&R) surgery., Design: Case series., Participants: Two children with isolated achiasma., Methods: Ophthalmologic examinations, brain magnetic resonance imaging, full-field and multifocal electroretinography (ERG), visual evoked potentials (VEPs), spectral-domain optical coherence tomography (OCT), eye-movement recordings, and unilateral T&R in 1 patient., Main Outcome Measures: Visual acuity before and after surgery, macular anatomic features and function, and eye velocity before and after T&R surgery in 1 patient., Results: Magnetic resonance imaging and VEP confirmed absence of decussation of retinofugal fibers in both patients. Visual acuity was 20/100 and 20/200. The anatomic features and function of the fovea and macula were normal by OCT and multifocal ERG. After T&R, there was a marked reduction in horizontal eye velocity and monocular visual acuity improved to 20/80., Conclusions: The finding that the macula is normal in achiasma suggests that reduced acuity is the result of retinal image motion from nystagmus. Two-muscle T&R reduces horizontal retinal image motion and can improve visual acuity in achiasma or patients with infantile nystagmus., (Copyright © 2013 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.)

Congenital achiasma offers a rare opportunity to study reorganization and inter-hemispheric communication in the face of anomalous inputs to striate cortex. We report neuroimaging studies of a patient with seesaw nystagmus, achiasma, and full visual fields. The subject underwent structural magnetic resonance imaging (MRI), diffusion tensor imaging (DTI) studies, and functional MRI (fMRI) using monocular stimulation with checkerboards, motion, objects and faces, as well as retinotopic quadrantic mapping. Structural MRI confirmed the absence of an optic chiasm, which was corroborated by DTI tractography. Lack of a functioning decussation was confirmed by fMRI that showed activation of only ipsilateral medial occipital cortex by monocular stimulation. The corpus callosum was normal in size and anterior and posterior commissures were identifiable. In terms of the hierarchy of visual areas, V5 was the lowest level region to be activated binocularly, as were regions in the fusiform gyri responding to faces and objects. The retinotopic organization of striate cortex was studied with quadrantic stimulation. This showed that, in support of recent findings, rather than projecting to an ectopic location contiguous with the normal retinotopic map of the ipsilateral temporal hemi-retina, the nasal hemi-retina's representation overlapped that of the temporal hemi-retina. These findings show that congenital achiasma can be an isolated midline crossing defect, that information transfer does not occur in early occipital cortex but at intermediate and higher levels of the visual hierarchy, and that the functional reorganisation of striate cortex in this condition is consistent with normal axon guidance by a chemoaffinity gradient., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Background: The purpose of this paper is to report a case of idiopathic isolated fovea plana showing asymmetry in the multifocal electroretinogram (mfERG)., Methods: We carried out optical coherence tomography (OCT) imaging, macular pigment density measurement, genetic testing and electrophysiological testing with visual evoked potentials and mfERGs on a young, highly myopic female of Pakistani origin, who had good visual acuity and no nystagmus., Results: OCT imaging revealed a complete absence of any foveal pit in either eye. Macular pigment density was normal and visual evoked potentials indicated normal chiasmal crossings, excluding albinism. Genetic testing revealed normal PAX6 coding data, excluding aniridia as a cause. mfERGs showed asymmetry consistent with off-centre fixation to the temporal side of the fovea in both eyes, but were otherwise normal., Conclusion: Lack of a foveal pit is a well-known finding in conditions such as oculocutaneous albinism and PAX6 gene-related aniridia. Isolated fovea plana is less common, and this case illustrates that the absence of a foveal pit does not necessarily result in a poor visual outcome. The finding of asymmetry in the mfERG in such a case is novel, and may indicate a functional adaptation to the structure of the fovea.

Purpose: To evaluate the correlation between multifocal pattern electroretinography (mfPERG) and Fourier-domain optical coherence tomography (FD-OCT) with regard to macular and retinal nerve fiber layer (RNFL) thickness in eyes with temporal hemianopia from chiasmal compression., Methods: Twenty-five eyes from 25 patients with permanent temporal visual field defects from chiasmal compression and 25 healthy eyes were submitted to mfPERG using a stimulus pattern of 19 rectangles, standard automated perimetry and FD-OCT measurements. The mfPERG response was determined for groups of three rectangles for the nasal and temporal hemifields and for each quadrant. Macular thickness measurements were registered according to an overlaid OCT-generated checkerboard with 36 checks and averaged for the central area, and for each scanned quadrant and hemifield. RNFL thickness was determined for all twelve 30-degree segments around the disc, and averaged for the segments corresponding to the 6, 7, 8, 9, 10, 11 and 12 o'clock position. Correlations were verified with Pearson's correlation coefficients and linear regression analysis., Results: Both mfPERG amplitudes and OCT measurements were significantly smaller in eyes with temporal visual field defects than in normals. A significant and strong correlation was found between most mfPERG and macular or RNFL thickness OCT parameters., Conclusions: mfPERG amplitudes and OCT measurements are significantly correlated in patients with chiasmal compression. Both technologies can quantify neuronal loss and, if used in combination, may help clarify structure-function relationships in this patient population.

A case of closed head trauma, harbouring bitemporal hemianopsia is presented. The MRI evaluation describes chiasmal contusion as the cause behind visual deficits. Chiasmal injury may occur even in the absence bony chip impingement and features of hypo-pituitarism. Such a situation warrants MRI evaluation of optic pathways.

Dissociated vertical divergence (DVD) is frequently associated with the infantile strabismus syndrome. There are different theories on the pathomechanism of this disorder, but none of them is generally accepted. Some authors believe that the slow upward movement of the covered eye is due to a different illumination of both retinae and consequently an unequal activity of the oculomotor nerve's nuclei. In one hypothesis a predominance of crossing pupillary tract fibres from the pretectal area to motor and parasympathetic nuclei of the oculomotor nerve was supposed. The consequence of this abnormal pathway in the midbrain would be a pronounced contraction anisocoria in patients with DVD. In contraction anisocoria the directly illuminated pupil contracts more strongly than the contralateral pupil without any efferent defect. In a small study we compared direct and indirect pupillary light reflexes in 11 DVD patients and 10 normal subjects. We found no significant differences of contraction anisocoria between the two groups. The results do not support the hypothesis of a different pupillary tract pathway in the midbrain of patients with DVD., (Georg Thieme Verlag KG Stuttgart · New York.)

Induction of demyelination in the central nervous system induce the oligodendrocyte progenitors to proliferate, migrate, and differentiate for restoring new myelin sheathes around demyelinated axons. Factors which increase the response of endogenous progenitor cells could be used to improve remyelination. In the current study, the effect of bFGF on lysolecithin-induced demyelination and remyelination processes in mouse optic chiasm and nerves was investigated. Lysolecithin was injected into the optic chiasm of Balb/C mice. Two groups of animals received doses of bFGF (1 or 5 ng/kg i.p.) just before and every 3 days after lysolecithin injection. Delay and amplitude of visual evoked potential (VEP) waves were recorded as indices of axonal demyelination at 7th, 13th, and 28th days post-lesion. Myelin basic protein (MBP) and Olig2 gene expressions were studied as indices of myelination and oligodendrocyte precursors' recruitment into the lesion. Lysolecithin elongated delay of P1 wave and declined the amplitude of P1-N1 wave. Lysolecithin decreased MBP and increased Olig2 expression in different days post-lesion. Lysolecithin-induced changes in VEPs were partially ameliorated by endogenous repair. bFGF reduced the increased delay, increased the reduced amplitude of P1-N1 wave, increased MBP gene expression, and accelerated the increasing pattern of Olig2. bFGF seems to be able to potentiate the endogenous repair mechanisms of myelin. Its effect on demyelination and remyelination processes seems to be mediated by oligodendrocyte progenitor cells and their differentiation to myelinating cells.

Purpose: The purpose of the study was to investigate the diagnostic ability of the neurologic hemifield test (NHT) and retinal nerve fiber layer (RNFL) thickness measurements to detect chiasmal compression., Methods: Thirty-seven patients with chiasmal compression, 35 patients with glaucoma, and 30 patients with glaucoma suspect were enrolled. The NHT score was established from a 30-2 visual field pattern deviation probability plot. Each test point value was calculated for a number that was inversely proportional to its pattern deviation probability. The NHT score was the absolute value of the difference in the sum of the point scores for two symmetrical regions of 16 points on either side of the vertical meridian. RNFL thickness was scored from 0 to 10 according to the pattern of RNFL loss and probability of abnormality. Solely present nasal or temporal RNFL defects were scored high, and exclusively appearing superior or nasal RNFL defects were scored low. The differences in the NHT and RNFL scores among the three groups were compared. Diagnostic ability was assessed by receiver operating characteristic (ROC) analysis., Results: The NHT and RNFL scores were significantly higher in patients with chiasmal compression than in patients with glaucoma and glaucoma suspect. The area under the ROC curve (AROC) was 0.734 of the NHT score and 0.613 of the RNFL score. When AROC was calculated using the NHT and RNFL scores concurrently, AROC was increased to 0.807., Conclusions: The NHT score and RNFL score have diagnostic ability to detect chiasmal compression, and simultaneous assessment of NHT and RNFL scores improves the diagnostic power.

Compression induced by a pituitary tumor on the optic chiasm can generate visual field deficits, yet it is unknown how this compression affects the retinotopic organization of the visual cortex. It is also not known how the effect of the tumor on the retinotopic organization of the visual cortex changes after decompression. The authors used functional MRI (fMRI) to map the retinotopic organization of the visual cortex in a 68-year-old right-handed woman before and 3 months after surgery for a recurrent pituitary macroadenoma. The authors demonstrated that longitudinal changes in visual field perimetry, as assessed by the automated Humphrey visual field test, correlated with longitudinal changes in fMRI activation in a retinotopic manner. In other words, after decompression of the optic chiasm, fMRI charted the recruitment of the visual cortex in a way that matched gains in visual field perimetry. On the basis of this case, the authors propose that fMRI can chart neural plasticity of the visual cortex on an individual basis and that it can also serve as a complementary tool in decision making with respect to management of patients with chiasmal compression.

Achiasmia is a rare disorder of visual pathway maldevelopment that can show diverse clinical and magnetic resonance imaging spectra. The aim of this study was to define the characteristics of visual evoked potentials (VEPs) that differentiate abnormal optic-nerve-fibre decussation in children with achiasmia versus children with albinism and healthy children. In four children with achiasmia, the following VEP characteristics were studied and compared to children with ocular albinism and with healthy control children: (a) flash and pattern onset VEP interhemispheric asymmetry; (b) flash N2, P2 and onset C1 amplitudes and latencies; (c) interocular polarity differences in interhemisphere potentials; and (d) chiasm coefficients (CCs). In the children with achiasmia, VEPs were related to an absence of or reduced optic-nerve-fibre decussation at the chiasm and showed: ipsilateral asymmetry, significantly higher VEP amplitudes over the ipsilateral hemisphere (p < 0.05), interocular inverse polarity and negative CC. Other VEP features (uncrossed asymmetry and positive CC) were also seen if additional visual pathway maldevelopment (such as severe optic nerve hypoplasia and/or absence of the optic tractus on one side) were associated with achiasmia. In the children with albinism, the VEPs were related to excess optic-nerve-fibre decussation at the chiasm and showed: contralateral asymmetry, significantly higher VEP amplitudes over the contralateral hemisphere (p < 0.001), interocular inverse polarity and negative CC. In achiasmia and albinism, the VEPs to flash stimulation were more robust and more clearly distinguished between the conditions compared with the VEPs to pattern onset stimulation. VEPs in achiasmia are associated with absent or reduced optic-nerve-fibre decussation, where ipsilateral interhemispheric asymmetry is associated with interocular inverse polarity and a negative CC.

Purpose: To evaluate the relationship between macular ganglion cell complex (GCC) parameters and visual field (VF) parameters in chiasmal compression and the potential for GCC parameters in order to predict the short-term postsurgical VF., Methods: Twenty-three eyes of 12 patients with chiasmal compression and 33 control eyes were studied. All patients underwent transsphenoidal tumor resection. Before surgery a 3D scan of the macula was taken using spectral-domain optical coherence tomography. All patients underwent Humphrey 24-2 VF testing after surgery. Spearman's rank correlation coefficients were used to evaluate the relationship between the GCC parameters and VF parameters [mean deviation (MD), pattern standard deviation]. Coefficients of determination (R2) were calculated using linear regression., Results: Average thickness in the patients was significantly thinner than that of controls. Average thickness, global loss volume and focal loss volume (FLV) significantly correlated with the MD. We observed the greatest R2 between FLV and MD., Conclusions: Examining the macular GCC was useful for evaluating structural damage in patients with chiasmal compression. Preoperative GCC parameters, especially FLV, may be useful in predicting visual function following surgical decompression of chiasmal compression.

Purpose: To investigate the potential of the optical coherence tomography (OCT) measurement of retinal nerve fiber layer (RNFL) thickness and ganglion cell complex (GCC) area and photopic negative response (PhNR) for predicting postoperative visual outcome in chiasmal compression, prospectively., Methods: Eighteen eyes of 18 patients undergoing chiasmal decompression surgery were prospectively assessed before, and 3 months after surgery with standard automated perimetry (SAP), OCT, and PhNR. Preoperative measurements were compared with 20 eyes of 20 age-matched controls. Spearman's correlation and regression analyses were conducted to evaluate the relationship between preoperative RNFL thickness, GCC area, PhNR/b-wave amplitude ratio, postoperative mean deviation (MD) and temporal visual field sensitivity (1/Lambert)., Results: Preoperative measurements of RNFL thickness, GCC area, and PhNR/b-wave amplitude ratio were reduced significantly in patients compared with normal controls. Preoperative RNFL thickness of the temporal quadrant, GCC area, and PhNR/b-wave amplitude ratio were correlated significantly with postoperative MD and temporal visual field sensitivity (1/Lambert)., Conclusions: An eye with the more demonstrable structural deterioration, as shown by reduced RNFL thickness and GCC area, and retinal ganglion cell dysfunction as shown by decreased PhNR/b-wave amplitude ratio was associated with the worse visual fields outcome. RNFL thickness and GCC area measurements using OCT and PhNR/b-wave amplitude ratio could be a useful prognostic indicator in the preoperative assessment of chiasmal compression.

Tuberculous meningitis is primarily a disease of the meninges of brain and spinal cord along with adjacent brain parenchyma. The characteristic pathological changes are meningeal inflammation, basal exudates, vasculitis and hydrocephalus. Tuberculous meningitis has a strong predilection for basal parts of the brain. Exudates, if dominantly present in the interpeduncular, suprasellar and Sylvian cisterns, result in optochiasmatic arachnoiditis and tuberculoma. Optochiasmatic arachnoiditis and tuberculoma are devastating forms of tuberculous meningitis and often associated with profound vision loss. This clinical entity more frequently affects young adults. In a recent study, on the multivariate logistic regression analysis, female sex, younger age and raised cerebrospinal fluid protein content were identified as predictors for developing optochiasmatic arachnoiditis. Frequently, optochiasmatic tuberculoma and optochiasmatic arachnoiditis develop paradoxically while a patient is being treated with anti-TB drugs. MRI reveals confluent enhancing lesions that are present in the interpeduncular fossa, pontine cistern, and the perimesencephalic and suprasellar cisterns. Management of tuberculous optochiasmatic arachnoiditis and optochiasmatic arachnoiditis tuberculoma has been variable. Treatment of optochiasmatic arachnoiditis continues to be a challenge and the response is generally unsatisfactory. In isolated case reports and in small series, corticosteroids, methyl prednisolone, thalidomide and hyaluronidase have been used with variable success. The benefit from neurosurgery is controversial and deterioration may follow the initial temporary improvement. Management of paradoxical optochiasmatic arachnoiditis is also controversial. Some patients regain vision following treatment with anti-TB drugs and continued usage of corticosteroids. Neurosurgery may be considered in the patients with either treatment failure or when diagnosis is in doubt. In conclusion, presence of optochiasmatic arachnoiditis or tuberculoma has important therapeutic and prognostic implications for patients of tuberculous meningitis.

Objective: Patients with pituitary insufficiency often experience some degree of impaired sleep. Sleep-wake rhythm is regulated to a large extent by the suprachiasmatic nucleus (SCN). Because the SCN is located just superior to the optic chiasm, we hypothesized that a history of compression of the optic chiasm (CC) due to a tumour with suprasellar extension is associated with altered sleep patterns in patients with pituitary insufficiency., Design: Case-control study., Patients: We studied 38 patients (mean age 55·7 ± 13·1 years; 71·1% men) with CC and 18 patients (mean age 53·3 ± 16·6 years, 38·9% men) without CC., Measurements: Objective measures of sleep patterns were assessed by wrist actigraphy. Validated sleep questionnaires were used to evaluate subjective sleep parameters., Results: Objective total sleep duration was 36 min shorter in patients with CC than in patients without CC [454 (295-553) vs 490 (432-740) min, P = 0·034]. Moreover, patients with CC had a later habitual bedtime [23:15 (22:30-03:00) vs 22:55 (20:00-02:00) h, P = 0·044] and a later actigraphic sleep onset [23:57 (22:31-01:33) vs 23·16 (19:47-03:04) h, P = 0·020]. Linear regression analysis confirmed the difference in total sleep duration after adjustment for age, sex, body mass index, cranial radiotherapy and pituitary/hypothalamic surgery. Subjective sleep parameters were similar in both groups., Conclusions: Compression of the optic chiasm due to a tumour with suprasellar extension is associated with permanent changes in total sleep duration in patients with pituitary insufficiency., (© 2011 Blackwell Publishing Ltd.)

Endoscopic pituitary surgery has been gaining wide acceptance as the first-line treatment of most functional pituitary adenomas. This technique has many advantages over traditional procedures, and growing evidence supports its use for endocrine control of functioning tumors. This article reviews data on the different modalities of treatment of functioning pituitary adenomas and compares the results. Endoscopic pituitary surgery controls tumor growth and endocrinopathy as well as or better than other treatment modalities. Complication rates are low and patient recovery is fast. Furthermore, surgery provides a means of achieving prompt decompression of neurologic structures and endocrine remission., (Copyright © 2011. Published by Elsevier Inc.)

A 5-year-old female presented to the emergency department with a 24-hour history of nausea, vomiting and mental status changes. Imaging demonstrated hemorrhage from a suprasellar mass consistent with an optic nerve glioma. The patient was taken to surgery for an open biopsy and hematoma evacuation. Pathology revealed a grade 3 fibrillary astrocytoma. She was subsequently treated with carboplatin and vincristine and is now 2 years out without evidence of recurrence. Apoplexy is a rare presentation for an optic pathway glioma. To the authors' knowledge, this is the first reported case in the pediatric population. Clinical presentation appears similar to the symptoms observed in pituitary apoplexy. Timely surgery should be directed at obtaining diagnostic tissue, prevention of long-term nervous system damage and evacuation of the hematoma where feasible., (Copyright © 2012 S. Karger AG, Basel.)

Examination of the pupil offers an objective evaluation of visual function as well as the vegetative pathways to the eye. Essential information is gathered within a short time. This makes pupillary inspection a valuable part of the routine ophthalmological, neurological and general medical examinations. Due to the proximity of pupillary pathways to various anatomic structures, pupillary dysfunction can be caused by a variety of disorders, some of which may be life threatening. The ophthalmologist plays a key role in detecting pupillary disorders and in directing further investigations. Therefore, one should have a good knowledge of the diagnostic significance of pupillary function and dysfunction., (© Georg Thieme Verlag KG Stuttgart · New York.)

A 62-year-old man awoke from aortic valve replacement surgery with a total loss of vision in his right eye and a temporal visual field defect in his left eye. Automated visual field examination confirmed a right-sided anterior junction syndrome, and a right-sided chiasmal infarct was demonstrated by MRI. Although rare, chiasmal stroke is a potential complication of open-heart surgery.

Purpose: The aim of this study was to test the correlation between Fourier-domain (FD) optical coherence tomography (OCT) macular and retinal nerve fibre layer (RNFL) thickness and visual field (VF) loss on standard automated perimetry (SAP) in chiasmal compression., Methods: A total of 35 eyes with permanent temporal VF defects and 35 controls underwent SAP and FD-OCT (3D OCT-1000; Topcon Corp.) examinations. Macular thickness measurements were averaged for the central area and for each quadrant and half of that area, whereas RNFL thickness was determined for six sectors around the optic disc. VF loss was estimated in six sectors of the VF and in the central 16 test points in the VF. The correlation between VF loss and OCT measurements was tested with Spearman's correlation coefficients and with linear regression analysis., Results: Macular and RNFL thickness parameters correlated strongly with SAP VF loss. Correlations were generally stronger between VF loss and quadrantic or hemianopic macular thickness than with sectoral RNFL thickness. For the macular parameters, we observed the strongest correlation between macular thickness in the inferonasal quadrant and VF loss in the superior temporal central quadrant (rho=0.78; P<0.001) whereas for the RNFL parameters the strongest correlation was observed between the superonasal optic disc sector and the central temporal VF defect (rho=0.60; P<0.001)., Conclusion: Although FD-OCT RNFL and macular thickness measurements were both correlated with VF loss, the correlation was stronger with quadrantic macular than with RNFL thickness measurements in patients with temporal hemianopia. Such measurements could potentially be used to quantify neuronal loss in patients with chiasmal compression.

A 51-year-old woman underwent craniotomy for removal of a pituitary tumor. At surgery, anomalous tissue was found projecting forward from the anterior angle of the optic chiasm. Termed "the chiasmal spur," this anomaly has been described previously in 5 patients, all as an incidental finding at autopsy. Our case is the first instance of the chiasmal spur being discovered and photographed intraoperatively.

A 27-year-old pregnant woman reported progressive loss of vision. Brain MRI disclosed an intracranial mass compressing the optic nerves and chiasm with imaging features suggestive of meningioma. Because delivery was imminent, surgical removal was deferred. Within a few days after delivery, the patient noted improvement in vision. Subsequent neuro-ophthalmological evaluations documented almost complete visual recovery within 2 months postpartum. The mass was removed surgically at 10 months postpartum. It was a grade I meningioma with progesterone cell surface receptors. The patient's visual function has remained stable during a follow-up of 14 months. This is the first reported case with full visual function and MRI documentation of spontaneous postpartum visual recovery in a progesterone receptor-positive meningioma compressing the anterior visual pathway.

Background: During development axons encounter a variety of choice points where they have to make appropriate pathfinding decisions. The optic chiasm is a major decision point for retinal ganglion cell (RGC) axons en route to their target in order to ensure the correct wiring of the visual system. MicroRNAs (miRNAs) belong to the class of small non-coding RNA molecules and have been identified as important regulators of a variety of processes during embryonic development. However, their involvement in axon guidance decisions is less clear., Methodology/principal Findings: We report here that the early loss of Dicer, an essential protein for the maturation of miRNAs, in all cells of the forming retina and optic chiasm leads to severe phenotypes of RGC axon pathfinding at the midline. Using a conditional deletion approach in mice, we find in homozygous Dicer mutants a marked increase of ipsilateral projections, RGC axons extending outside the optic chiasm, the formation of a secondary optic tract and a substantial number of RGC axons projecting aberrantly into the contralateral eye. In addition, the mutant mice display a microphthalmia phenotype., Conclusions: Our work demonstrates an important role of Dicer controlling the extension of RGC axons to the brain proper. It indicates that miRNAs are essential regulatory elements for mechanisms that ensure correct axon guidance decisions at the midline and thus have a central function in the establishment of circuitry during the development of the nervous system.

Background: Vision impairment is a devastating complication of tuberculous meningitis. In the present study we evaluated the predictors and prognostic significance of vision impairment in tuberculous meningitis., Methods: In this study, 101 adult patients with tuberculous meningitis were evaluated for vision status and physical disability and were followed up for 6 months. Contrast enhanced magnetic resonance imaging (MRI) was performed at baseline and 6 months., Result: Out of 101 patients, 74 patients had normal vision and 27 patients had low vision or blindness at enrollment. Thirteen patients died during the study period. Out of 88 patients who survived at 6 months, 68 patients had good vision, 11 patients had low vision and 9 patients had blindness. Predictors of vision deterioration were papilledema, cranial nerve palsies, raised cerebrospinal fluid protein (>1g/L), and presence of optochiasmatic arachnoiditis in MRI. Predictors of blindness, at 6 months, were found to be papilledema, vision acuity < or =6/18, cranial nerve palsies, tuberculous meningitis stage II or III, raised cerebrospinal fluid protein (>1g/L), optochiasmatic arachnoiditis, and optochiasmal tuberculoma. At 6 months, 27 patients had death or severe disability. Predictors of death or severe disability at 6 months were vision acuity < or =6/18, cranial nerve deficits, hemiparesis, clinical stage II or III, and presence of infarct in MRI., Conclusion: Vision impairment occurred in one-fourth of patients with tuberculous meningitis. Principal causes of vision loss were optochiasmatic arachnoiditis and optochiasmal tuberculoma. Impaired vision predicted death or severe disability.

Classically, the pupillary pathway is considered as a simple reflex arc comprising retinal ganglion cells, midbrain interneurons, oculomotor nerve and short ciliary nerves. However, there are some specialties in the construction of the pupillary pathways that have to be kept in mind when dealing with diseases involving pupillary disorders. This may help to localise lesions. Additionally, studies in patients with lesions of the retrogeniculate pathways have shown that pupillary disorders are possible even with lesions not involving the classical reflex arc. The pupil is therefore not only controlled subcortically, some components are influenced by the visual cortex. The aim of this article is to clarify various findings and terms such as relative afferent pupillary defect and pupillary hemihypokinesia., ((c) Georg Thieme Verlag KG Stuttgart-New York.)