Predictive visual field outcomes after optic chiasm decompressive surgery by retinal vessels parameters using optical coherence tomography angiography

AIM:To evaluate the predictive value of superficial retinal capillary plexus(SRCP)and radial peripapillary capillary(RPC)for visual field recovery after optic cross decompression and compare them with peripapillary nerve fiber layer(pRNFL)and ganglion cell complex(GCC).METHODS:This prospective longitudinal observational study included patients with chiasmal compression due to sellar region mass scheduled for decompressive surgery.Generalized estimating equations were used to compare retinal vessel density and retinal layer thickness preand post-operatively and with healthy controls.Logistic regression models were used to assess the relationship between preoperative GCC,pRNFL,SRCP,and RPC parameters and visual field recovery after surgery.RESULTS:The study included 43 eyes of 24 patients and 48 eyes of 24 healthy controls.Preoperative RPC and SRCP vessel density and pRNFL and GCC thickness were lower than healthy controls and higher than postoperative values.The best predictive GCC and pRNFL models were based on the superior GCC[area under the curve(AUC)=0.866]and the tempo-inferior pRNFL(AUC=0.824),and the best predictive SRCP and RPC models were based on the nasal SRCP(AUC=0.718)and tempo-inferior RPC(AUC=0.825).There was no statistical difference in the predictive value of the superior GCC,tempo-inferior pRNFL,and tempo-inferior RPC(all P>0.05).CONCLUSION:Compression of the optic chiasm by tumors in the saddle area can reduce retinal thickness and blood perfusion.This reduction persists despite the recovery of the visual field after decompression surgery.GCC,pRNFL,and RPC can be used as sensitive predictors of visual field recovery after decompression surgery.

Toward a Multi-Layered Chiasme-Focused Topology: A Reading of Merleau-Ponty's Later Writings

This paper traces the genealogy of reversibility,chiasma,and chiasme in Merleau-Ponty's writings and offers a new characterisation of his later ontology in terms of a multi-layered chiasme-focused topology informed by subtle differences and interconnections among these notions.We need to grasp the significance of reversibility not only in terms of constant recoil and impossible overlap but also of its situatedness in the crisscrossing between Dasein and things,and between the inside/invisible and the outside/visible."Chiasma" was initially introduced as a reference to the intersection of perspectives.Merleau-Ponty deploys it to articulate macroscopic insights concerning the nature of philosophy and the interweaving connections between self,other,and the world.In comparison,"reversibility" is primarily used to describe the microscopic bond between touching-touched and perceiving-perceived.I argue that,as Merleau-Ponty's ultimate choice of wording,"chiasme" incorporated the significance of both "reversibility" and "chiasma." A chiasme-focused topology that retains the significance of all three of the terms would serve to better convey the import of Merleau-Ponty's later ontology,which aims to dissolve and to re-configure our conceptions about being,body,self,and the other from within and from below.

Neuropsychologic Testing in Chiasmal Patients Exhibiting Inattention in the Temporal Visual Space during Monocular Visual Testing

Objective: By means of neuropsychologic tests, to further analyse a specific chiasmal monocular visual testing behaviour, here labelled temporal blocking because of the elective ignorance of optotypes on the temporal side of the chart. Often it is combined with impairment of reading and other cognitive impairments. Methods: Eighteen patients with lesions to the chiasm and some degree of temporal blocking aged 24 - 76 years underwent: 1) tests for visual neglect (Gothenburg test;behavioural inattention tests: star cancellation;line bisection);2) visuo-perceptual tests;and 3) a test involving reading a crowded ten-letter and cipher bar. Results: The temporal blocking in two patients recovered after emergency neurosurgery and their results were normal when subsequently tested. Of the 16 patients with deficiencies, 14 had a poorer left eye (p Conclusions: The best neuropsychologic tests appeared to be those for visual neglect and the crowded bar test. In most cases, the right cerebral hemisphere’s lack of some crossed information from the left eye, usually needed for normative saccades and adjustment to visual space, may be a factor underlying the specific visual behaviour.

Central Retinal Microperimetry by Scanning Laser Ophthalmoscopy in Chiasmal Patients with Visual Inattention Temporally at Monocular Visual Acuity Testing

Background: In a previous study, a specific visual behaviour was described in four chiasmal patients. It manifested as inattention/ignorance within the temporal visual space (“visual blocking”) at monocular visual acuity testing. Moreover, in 3 out of the 4, the process of reading a text appeared cognitively impaired. Methods: As a supplement to conventional visual field testing, the present analysis focus was on microperimetry by Scanning Laser Ophthalmocopy (SLO). Our aim was to identify the perceptual retinal counterparts to the temporally located visual field defects as caused by the visual pathway lesion on a chiasmal level, possibly also to indicate the apparently ineffective saccadic movements underlying that only part of the line on the chart could be given. Results and Conclusions: The central retinal areas with lacking recognition by SLO testing were given by black rectangles expressing scotomatous points;they clustered in a zone extending nasally from the fixation area, as expected. The methodology further depicted an orderly fixation in two cases, and only minor deviation in two. Fixation saccades thus were considered by and large within normal and with only exceptional outlier points recorded. All considered, the shortcomings of the perceptual mechanisms underlying the lateralised visual inattention as observed in the four patients have remained without a satisfactory explanation.

Prognostic Value of Retinal Nerve Fiber Layer and Ganglion Cell Complex after Optic Chiasmal Decompression

This paper is an attempt to ascertain the role of the optical coherence tomography by measuring the retinal nerve fiber layer thickness and ganglion cell complex area to predict postoperative visual outcome after chiasmal decompression. 16 eyes scheduled for chiasmal decompression surgery were assessed before and 3 months after surgery with standard automated perimetry and OCT (optical coherence tomography). Preoperative RNFL (retinal nerve fibre layer) thickness and GCC (ganglion cell complex) area were compared with 20 normal control eyes. 13 cases were operated by microscopic assisted endoscopic endonasal transsphenoidal approach;the remaining 3 cases were operated transcranially. Spearman’s correlation analysis was used to evaluate the relationship between preoperative RNFL thickness, GCC area, postoperative mean deviation and temporal visual field sensitivity (1/Lambert). Preoperative measurements of RNFL thickness and all GCC area were significantly reduced in the patients compared with normal control. 3 months postoperative evaluation showed improvement of the visual field, but reduction in global and sectorial RNFL thickness except for nasal sector. Moreover, absolute postoperative (not pre-post change) visual field parameters were significantly correlated to preoperative RNFL (P = 0.00399 for mean deviation, P = 0.0023 for temporal sensitivity), GCC thickness (P = 0.00736 for mean deviation, P = 0.0469 for temporal sensitivity), with FLV (focal loss value) (P = 0.0012 for mean deviation, P = 0.0021 for temporal sensitivity) showed a higher correlation. Reduced RNFL thickness mainly, and GCC area minimally, were associated with the worst visual field outcome. FLV is a new prognostic value.

Optical coherence tomography in compressive lesions of the anterior visual pathway

Optical coherence tomography(OCT)provides a non-invasive analysis of the retina in vivo.Lesions which compress the anterior visual pathway can cause anterograde and retrograde neuro-degeneration.Retrograde structural changes to the retina can be detected by OCT.Analyzing patterns of change on OCT can guide diagnostic and treatment decisions for lesions compressing the optic nerve and chiasm to minimize loss of visual function.From our review of current literature,it is clear that thinning of both the retinal nerve fiber and ganglion cell layers(GCLs)can indicate compression.These parameters correlate with visual function loss as detected by perimetry.Furthermore,these measurements have shown to be the most reliable biomarkers to date in predicting visual recovery after treatment of these compressive lesions.

Visual Disorders Outcome after Endoscopic Endonasal Trans-Sphenoidal Surgery of Pituitary Macroadenomas

Objective: Describe the outcome of visual disorders after endonasal transsphenoidal (EET) surgery of pituitary macroadenomas with preoperative chiasmal compression. Patients and Methods: From 2009 to 2013, 225 patients underwent EET surgery for sellar tumor. Among them, 168 suffered from visual disorders induced by chiasmatic compression, of which 88 met the inclusion criteria for this study. Average duration of follow up was 1.8 yrs ± 0.4 yrs. All patients had sellar MRI before surgery and yearly postoperatively, visual acuity (VA) and/or visual field (VF) measurements before, 3 months after surgery and yearly postoperatively. Results: All tumors were macroadenomas with a mean preoperative MRI-estimated volume of 10.0 {plus minus} 9.07 cm3. Preoperative VA was impaired with an average of 0.43 ± 0.13 LogMAR (left eye) and 0.36 ± 0.14 LogMAR (right eye) and VF was disturbed in 99% ± 2% of the cases with the most frequent disorder being bitemporal hemianopsia (38 patients). Post-operatively, the mean residual MRI-estimated tumor volume was 3.15 ± 3.71 cm3. Mean tumor volume reduction was 62% ± 9% (p < 0.001). Optic chiasmal compression resolved in 72% ± 10% of the cases. Visual function improved in 86% ± 7% of cases (p < 0.001). Conclusion: Endoscopic endonasal management of pituitary gland neoplasms is effective to reduce tumor volume. This technique achieved significant visual improvement in the majority of cases presenting with chiasmal compression syndrome.

Communicology Chiasm： The Play of Tropic Logic in Bateson and Jakobson

Gregory Bateson is famous for his description of the ＂double bind＂ that occurs when human （and animal） communication interaction becomes dysfunctional/-/is principal example is the ＂nip versus bite＂ opposition that he observed when a human and a dog （or two monkies） ＂play＂ （nip） and then play turns to ＂work＂ （bite）.The model is a semiotic failure by not accounting for negation, i.e., ＂labor＂ （not-nip） and ＂leisure＂ （not-bite）. Thus, if there is a double bind, there must be a foundational apposition condition of single-bind （functional communication） in the system, i.e., the possibility of an actual choice, which logically entails a not-choice [potential ＂new＂ choice]. The play/work versus leisure/labor distinction by combination goes back at least to Plato, and in modernity to Ernst Cassirer and Karl Buhler, but has its most strategic communicological development in Maurice Merleau-Ponty＇s tropic logic thesis on Chiasm. The thesis is better known through its application by Roman Jakobson and Claude L6vi-Strauss as a tropic logic of metaphor （attribute--substance quality） and metonymy （part--whole quantity）. My analysis illustrates the tropic logic by contrasting a fundamental metaphysical thesis that Being/Having （Play--Work） and Becoming/Doing （Leisure--Labor） must be phenomenological （tropic） as a basis for Semiotics （logic）. Thus in Communicology, Play is a ＂pretend reality＂ of actual agency, and, Playing is a ＂pretended action in Play＂ of symbolic agency.

Molecular guidance cues in the development of visual pathway

70%-80% of our sensory input comes from vision. Light hit the retina at the back of our eyes and the visual information is relayed into the dorsal lateral geniculate nuclei （dLGN） and primary visual cortex （V1） thereafter, constituting the image-forming visual circuit. Molecular cues are one of the key factors to guide the wiring and refinement of the image-forming visual circuit during pre- and post-embryonic stages. Distinct molecular cues are involved in different developmental stages and nucleus, suggesting diverse guidance mechanisms. In this review, we summarize molecular guidance cues throughout the image-forming visual circuit, including chiasm determination, eye-specific segregation and refinement in the dLGN, and at last the reciprocal con- nections between the dLGN and VI.

Biomechanics of human optic chiasmal compression: ex vivo experiment and finite element modelling

The mechanism of bitemporal hemianopia arising as a result of chiasmal compression is unknown.In this study,we combined an ex vivo experiment and finite element modelling(FEM)to investigate its potential mechanism.A cadaveric human optic chiasm was scanned using micro-CT before and after deformation by inflation of Foley catheter,to simulate tumour growth from beneath.The geometry of the same chiasm was reconstructed and simulated using finite element analysis.Chiasmal deformations were extracted from the simulation and compared with those observed during micro-CT scanning.In addition,nerve fibre models examining variation in local fibre distribution patterns of the chiasm were incorporated to investigate the strain(deformation)distributions of the chiasm at an axonal level.The FEM model matched the micro-CT scans well both qualitatively and quantitatively.Compression of the chiasm induced high strains in the paracentral portions of the chiasm where the crossing optic nerve fibres are located.At an axonal level,the magnitude of strains affecting crossed fibres were greater than those affecting uncrossed fibres.The high strains in the paracentral portions of the chiasm,combined with the differences in strain between crossed and uncrossed nerve fibres,are consistent with a biomechanical explanation for the pattern of visual field loss seen in chiasmal compression.

French Chiasm Communicology and the Discourse Model of the Human Sciences

The French discourse model of human communication is largely an engagement of the problematic concept of enlightenment as a product of the ability to reason by thinking.The engagement as speaking and writing becomes thematic,when one considers that,the product called“reason”also should explicate the process wherein the conscious experience of being is essentially“reasonable”in doing as listening and reading.The engaged analysis of reason differentiates among parole,discours,langue,and langage as a synthesis of logic mediating rhetoric and grammar as models of expression and perception.The method is known as the trivium in the Medieval universities of Europe,subsequently adopted as a pedagogy throughout Europe,and last,adopted by C.S.Peirce as a foundational semiotic methodology for science(methodeutic).The influence of the human science adaptations emerges in France with the philosophic cross-over and intertwined(chiasm)positions of Existentialism,Phenomenology,Structuralism,and Semiology.Doing the reasonable requires metaphor and metonymy,simile and synecdoche in the service of expression,yet,it also demands the perception of their respective counterparts in allegory,analogy,allegoresis,and aphorism.The human journey from thinking to speaking to doing and the return(renvoi)is one of ingenuity made eloquent in the face of crisis.It was so for the Ionian enlightenment,it was so for the European enlightenment,and it is so for us.

Playing Inside the Lines： The Fold, the Dispositif, and the Return Home

This paper seeks to examine a particular aspect of the communicological dynamic of play and boundaries. Working from an existential concept of play as creative, dialogic expression （and as the vehicle of new experience and new thought）, I will explore the human experience of limits, borders, and scaffolds. The existence of a grammar is vital to the function of both a language and a cultural system. But, as speakers and participants, we do not learn the language from the outside in. That is, we start speaking the language before we know anything about it. As infants, we hear sounds and observe gestures and we imitate them. Within this fold, we gain consciousness of an outside. Mastery of grammars and codes enable us to enter worlds seemingly closed off by boundaries, seemingly transforming alien and outsider status into group membership and inhabitant. As such, this paper opens up the question of what it means to be outside and inside. The standpoint of this paper is semiotic, phenomenological, and psychoanalytic. To this end, the essay will closely engage with the thinking of Merlean-Ponty, Deleuze, Foucault, and Kristeva.