AASH Newsletter Fall 99-Ver.2
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Fluids Hypertension Syndromes: Migraines, Headaches, Normal Tension Glaucoma, Benign Intracranial Hypertension, Caffeine Intolerance
Fluids Hypertension Syndromes – Dr. Leonardo Izecksohn – page 1 Fluids Hypertension Syndromes: Migraines, Headaches, Normal Tension Glaucoma, Benign Intracranial Hypertension, Caffeine Intolerance. Etiologies, Pathophysiologies and Cure. Author: Leonardo Izecksohn. Medical Doctor, Ophthalmologist, Master of Public Health. We have no financial interest on any medicament, device, or technique described in this e-book. We authorize the free copy and distribution of this e-book for educational purposes. The 1st. edition was written at the year 1996, with 2 pages. There are other editions spread at the Internet. This is the enlarged and revised edition 65-f, updated on May 24, 2016. ISBN 978-85-906664-1-7 DOI: 10.13140/2.1.3074.5602 www.izecksohn.com/leonardo/ [email protected] Fluids Hypertension Syndromes – Dr. Leonardo Izecksohn – page 2 Abstract A – Migraines, Headaches and Fluids Hypertension Syndromes – What are they? - Answer: Migraines and most primary headaches are the aches of the pressure increase in the fluids: - Intraocular Aqueous Humor, - Intracranial Cerebrospinal Fluid, and - Inner ear’s Perilymph and Endolymph. We denominate the fluids’ pressure rises and their consequent migraines, signs, symptoms and sick- nesses as the Fluids Hypertension Syndromes. Migraines and headaches are not sicknesses: they are symptoms of the sicknesses. B – How many Fluids Hypertension Syndromes do exist? - Answer: There are three Fluids Hypertension Syndromes: 1- Ocular, due to raises of the intraocular Aqueous Humor pressure. 2- Cerebrospinal, due to raises of the intracranial Cerebrospinal Fluid pressure. 3- Inner Ears, due to raises of the inner ears' Perilymph and Endolymph pressures. Each patient can present one, two, or all the three Fluids Hypertension Syndromes in the same time. -
Subliminal Afterimages Via Ocular Delayed Luminescence: Transsaccade Stability of the Visual Perception and Color Illusion
ACTIVITAS NERVOSA SUPERIOR Activitas Nervosa Superior 2012, 54, No. 1-2 REVIEW ARTICLE SUBLIMINAL AFTERIMAGES VIA OCULAR DELAYED LUMINESCENCE: TRANSSACCADE STABILITY OF THE VISUAL PERCEPTION AND COLOR ILLUSION István Bókkon1,2 & Ram L.P. Vimal2 1Doctoral School of Pharmaceutical and Pharmacological Sciences, Semmelweis University, Budapest, Hungary 2Vision Research Institute, Lowell, MA, USA Abstract Here, we suggest the existence and possible roles of evanescent nonconscious afterimages in visual saccades and color illusions during normal vision. These suggested functions of subliminal afterimages are based on our previous papers (i) (Bókkon, Vimal et al. 2011, J. Photochem. Photobiol. B) related to visible light induced ocular delayed bioluminescence as a possible origin of negative afterimage and (ii) Wang, Bókkon et al. (Brain Res. 2011)’s experiments that proved the existence of spontaneous and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat’s whole eye, lens, vitreous humor and retina. We also argue about the existence of rich detailed, subliminal visual short-term memory across saccades in early retinotopic areas. We conclude that if we want to understand the complex visual processes, mere electrical processes are hardly enough for explanations; for that we have to consider the natural photobiophysical processes as elaborated in this article. Key words: Saccades Nonconscious afterimages Ocular delayed bioluminescence Color illusion 1. INTRODUCTION Previously, we presented a common photobiophysical basis for various visual related phenomena such as discrete retinal noise, retinal phosphenes, as well as negative afterimages. These new concepts have been supported by experiments (Wang, Bókkon et al., 2011). They performed the first experimental proof of spontaneous ultraweak biophoton emission and visible light induced delayed ultraweak photon emission from in vitro freshly isolated rat’s whole eye, lens, vitreous humor, and retina. -
Visual Perception in Migraine: a Narrative Review
vision Review Visual Perception in Migraine: A Narrative Review Nouchine Hadjikhani 1,2,* and Maurice Vincent 3 1 Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02129, USA 2 Gillberg Neuropsychiatry Centre, Sahlgrenska Academy, University of Gothenburg, 41119 Gothenburg, Sweden 3 Eli Lilly and Company, Indianapolis, IN 46285, USA; [email protected] * Correspondence: [email protected]; Tel.: +1-617-724-5625 Abstract: Migraine, the most frequent neurological ailment, affects visual processing during and between attacks. Most visual disturbances associated with migraine can be explained by increased neural hyperexcitability, as suggested by clinical, physiological and neuroimaging evidence. Here, we review how simple (e.g., patterns, color) visual functions can be affected in patients with migraine, describe the different complex manifestations of the so-called Alice in Wonderland Syndrome, and discuss how visual stimuli can trigger migraine attacks. We also reinforce the importance of a thorough, proactive examination of visual function in people with migraine. Keywords: migraine aura; vision; Alice in Wonderland Syndrome 1. Introduction Vision consumes a substantial portion of brain processing in humans. Migraine, the most frequent neurological ailment, affects vision more than any other cerebral function, both during and between attacks. Visual experiences in patients with migraine vary vastly in nature, extent and intensity, suggesting that migraine affects the central nervous system (CNS) anatomically and functionally in many different ways, thereby disrupting Citation: Hadjikhani, N.; Vincent, M. several components of visual processing. Migraine visual symptoms are simple (positive or Visual Perception in Migraine: A Narrative Review. Vision 2021, 5, 20. negative), or complex, which involve larger and more elaborate vision disturbances, such https://doi.org/10.3390/vision5020020 as the perception of fortification spectra and other illusions [1]. -
Phosphene Perception Is Due to the Ultra-Weak Photon Emission Produced in Various Parts of the Visual System: Glutamate in the Focus
Zurich Open Repository and Archive University of Zurich Main Library Strickhofstrasse 39 CH-8057 Zurich www.zora.uzh.ch Year: 2016 Phosphene perception is due to the ultra-weak photon emission produced in various parts of the visual system: glutamate in the focus Császár, Noémi ; Scholkmann, Felix ; Salari, Vahid ; Szőke, Henrik ; Bókkon, István Abstract: Phosphenes are experienced sensations of light, when there is no light causing them. The physiological processes underlying this phenomenon are still not well understood. Previously, we proposed a novel biopsychophysical approach concerning the cause of phosphenes based on the assumption that cellular endogenous ultra-weak photon emission (UPE) is the biophysical cause leading to the sensation of phosphenes. Briefly summarized, the visual sensation of light (phosphenes) is likely to be duetothe inherent perception of UPE of cells in the visual system. If the intensity of spontaneous or induced photon emission of cells in the visual system exceeds a distinct threshold, it is hypothesized that it can become a conscious light sensation. Discussing several new and previous experiments, we point out that the UPE theory of phosphenes should be really considered as a scientifically appropriate and provable mechanism to explain the physiological basis of phosphenes. In the present paper, we also present our idea that some experiments may support that the cortical phosphene lights are due to the glutamate-related excess UPE in the occipital cortex. DOI: https://doi.org/10.1515/revneuro-2015-0039 Posted at the Zurich Open Repository and Archive, University of Zurich ZORA URL: https://doi.org/10.5167/uzh-126012 Journal Article Published Version Originally published at: Császár, Noémi; Scholkmann, Felix; Salari, Vahid; Szőke, Henrik; Bókkon, István (2016). -
Textbook of Ophthalmology, 5Th Edition
Textbook of Ophthalmology Textbook of Ophthalmology 5th Edition HV Nema Former Professor and Head Department of Ophthalmology Institute of Medical Sciences Banaras Hindu University Varanasi India Nitin Nema MS Dip NB Assistant Professor Department of Ophthalmology Sri Aurobindo Institute of Medical Sciences Indore India ® JAYPEE BROTHERS MEDICAL PUBLISHERS (P) LTD. New Delhi • Ahmedabad • Bengaluru • Chennai Hyderabad • Kochi • Kolkata • Lucknow • Mumbai • Nagpur Published by Jitendar P Vij Jaypee Brothers Medical Publishers (P) Ltd B-3 EMCA House, 23/23B Ansari Road, Daryaganj, New Delhi 110 002 I ndia Phones: +91-11-23272143, +91-11-23272703, +91-11-23282021, +91-11-23245672 Rel: +91-11-32558559 Fax: +91-11-23276490 +91-11-23245683 e-mail: [email protected], Visit our website: www.jaypeebrothers.com Branches 2/B, Akruti Society, Jodhpur Gam Road Satellite Ahmedabad 380 015, Phones: +91-79-26926233, Rel: +91-79-32988717 Fax: +91-79-26927094, e-mail: [email protected] 202 Batavia Chambers, 8 Kumara Krupa Road, Kumara Park East Bengaluru 560 001, Phones: +91-80-22285971, +91-80-22382956, 91-80-22372664 Rel: +91-80-32714073, Fax: +91-80-22281761 e-mail: [email protected] 282 IIIrd Floor, Khaleel Shirazi Estate, Fountain Plaza, Pantheon Road Chennai 600 008, Phones: +91-44-28193265, +91-44-28194897 Rel: +91-44-32972089, Fax: +91-44-28193231, e-mail: [email protected] 4-2-1067/1-3, 1st Floor, Balaji Building, Ramkote Cross Road Hyderabad 500 095, Phones: +91-40-66610020, +91-40-24758498 Rel:+91-40-32940929 Fax:+91-40-24758499, e-mail: [email protected] No. 41/3098, B & B1, Kuruvi Building, St. -
Permanent Central Scotoma Caused by Looking at the Sun During an Eclipse, and Complicated by Uniocular, Transi- Ent, Revolving Hemianopsia
PERMANENT CENTRAL SCOTOMA CAUSED BY LOOKING AT THE SUN DURING AN ECLIPSE, AND COMPLICATED BY UNIOCULAR, TRANSI- ENT, REVOLVING HEMIANOPSIA. From Dr. Knapp’s Practice, Reported by Dr. A. DUANE, New York. Reprinted from the Archives of Ophthalmology, Vol. xxiv., No. i, 1895 PERMANENT CENTRAL SCOTOMA CAUSED BY LOOKING AT THE SUN DURING AN ECLIPSE, AND COMPLICATED BY UNIOCULAR, TRANSI- ENT, REVOLVING HEMIANOPSIA. From Dr. Knapp’s Practice, Reported by Dr. A. DUANE, New York, instances of central scotoma after expos- ALTHOUGHure to sunlight are by no means rare, the subjoined case seems worthy ofrecord, because of the persistence of the scotoma twelve years afterwards, and because of the pres- ence of a peculiar hemiopic and scotoma scintil- lans, which apparently was likewise the result of the action of the sun’s rays. The patient, P. W., a man twenty-four years of age, consulted Dr. Knapp on Feb. 5, 1895, and gave the following history: Twelve years previous he had, on the occasion of the transit of Venus, 1 looked directly at the sun through the tube formed by the nearly closed fist. Soon after, he found that when both eyes were open, but not when the left was closed, a greenish cloud hid com- pletely the centre of every object looked at. This had exactly the shape of the illuminated portion of the sun at the time of the transit, i. e., was a circle with a crescentic defect at the upper part corresponding to the spot occupied by the planet at the time. It was then of considerable size, covering an area 5 inches in width when projected upon a surface 15 or 20 inches off. -
Taming Hallucinations: an Investigation of the Phenomenology and Precipitating Conditions of Visual
Taming hallucinations: An investigation of the phenomenology and precipitating conditions of visual hallucinations in the general population Sebastian Rogers A thesis in fulfilment of the requirements for the degree of Doctor of Philosophy School of Psychology Faculty of Science March 2019 Thesis/Dissertation Sheet Surname/Family Name : Rogers Given Name/s : Sebastian Liam Abbreviation for degree as give in the University calendar : PhD Faculty : Science School : Psychology Taming hallucinations: An investigation of the phenomenology and Thesis Title : precipitating conditions of visual hallucinations in the general population Abstract 350 words maximum: (PLEASE TYPE) Historically, the investigation of visual hallucinations has been hindered by the complexity and unpredictability of their occurrence and content. However, presenting individuals with luminance flicker confined to an annulus reliably induces visual hallucinations comprised of numerous shadowy, colourless, circular shapes rotating around the annular path, thereby facilitating objective mechanistic investigation of hallucinations by overcoming their unpredictability, heterogeneity, and complexity. The work presented in this thesis utilises these hallucinations in combination with behavioural and neuroscientific experimentation to explore processes underlying hallucination phenomenology, and the factors that precipitate individual hallucination episodes. The experiments reported in Chapter 2 probed the low- level visual features of induced hallucinations. Using a novel method for objectively estimating hallucination sensory strength, we present evidence that hallucination strength varies with the frequency of the inducing flicker. We also analysed the temporal dynamics of hallucinatory motion to test the claim that the hallucinations are bistable, and to unveil clues about their underlying neural processing. The experiments in Chapter 3 targeted the neural mechanisms that determine hallucination sensory strength. -
What Do Blind People “See” with Retinal Prostheses? Observations And
bioRxiv preprint doi: https://doi.org/10.1101/2020.02.03.932905; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 1 What do blind people “see” with retinal prostheses? Observations and qualitative reports of epiretinal 2 implant users 3 4 5 6 Cordelia Erickson-Davis1¶* and Helma Korzybska2¶* 7 8 9 10 11 1 Stanford School of Medicine and Stanford Anthropology Department, Stanford University, Palo Alto, 12 California, United States of America 13 14 2 Laboratory of Ethnology and Comparative Sociology (LESC), Paris Nanterre University, Nanterre, France 15 16 17 18 19 * Corresponding author. 20 E-mail: [email protected], [email protected] 21 22 23 ¶ The authors contributed equally to this work. 24 25 26 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.02.03.932905; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY 4.0 International license. 27 Abstract 28 29 Introduction: Retinal implants have now been approved and commercially available for certain 30 clinical populations for over 5 years, with hundreds of individuals implanted, scores of them closely 31 followed in research trials. Despite these numbers, however, few data are available that would help 32 us answer basic questions regarding the nature and outcomes of artificial vision: what do 33 participants see when the device is turned on for the first time, and how does that change over time? 34 35 Methods: Semi-structured interviews and observations were undertaken at two sites in France and 36 the UK with 16 participants who had received either the Argus II or IRIS II devices. -
Evaluation of Oxidative Stress in Migraine Patients with Visual Aura - the Experience of an Rehabilitation Hospital
Evaluation of oxidative stress in migraine patients with visual aura - the experience of an Rehabilitation Hospital Adriana Bulboaca1,4, Gabriela Dogaru2,4, Mihai Blidaru1, Angelo Bulboaca3,4, Ioana Stanescu3,4 Corresponding author: Gabriela Dogaru, E-mail address: [email protected] Balneo Research Journal DOI: http://dx.doi.org/10.12680/balneo.2018.201 Vol.9, No.3, September 2018 p: 303 –308 1- Department of Pathophysiology, Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania 2 -Department of PRM, Iuliu Haţieganu University of Medicine and Pharmacy Cluj-Napoca, Cluj-Napoca, Romania 3 - Department of Neurology, Iuliu Haţieganu University of Medicine and Pharmacy, Cluj-Napoca, Romania 4- Rehabilitation Hospital, Cluj-Napoca, Romania Abstract Background: Although there are previous studies regarding the migraine pathophysiology, the clinical entity of migraine with aura can have an different pathophysiological mechanism compared with migraine without aura. One of the most important mechanism in migraine is represented by increasing of oxidative stress. The aim of this study was to study the levels of two oxidative stress molecules: nitric oxide (NO) and malondialdehyde (MDA) in migraine with visual aura compared with migraine without aura. Material and Method: a Control group (healthy volunteers) of 37 patients and 58 patient with migraine divided in Group 1 (migraine with visual aura) and Group 2 (migraine without aura) were taken in the study. All the patient were assessed regarding the age, body mass index, blood pressure, basal glycaemia, smoking/non-smoking status, C reactive protein and fibrinogen. Visual aura was assessed regarding transitive negative visual symptoms or positive visual symptoms. Oxidative status was assessed by measurements of the plasma levels of NO and MDA. -
From Prehistoric Shamanism to Early Civilizations: Eye Floater Structures in Ancient Egypt*
May, 2012 Volume 12, No. 2 From Prehistoric Shamanism to Early Civilizations: Eye Floater Structures in Ancient Egypt* By Floco Tausin Abstract This article is based on the assumption that prehistoric shamanic rituals include the perception, interpretation and depiction of what we today know as eye floaters (muscae volitantes). It is suggested that, together with other shamanic symbols, floaters continue to be experienced and depicted not only in later shamanic societies up to the present day, but also entered the visual arts of early civilizations. The present article supports this thesis from the example of ancient Egypt. A closer look at Egyptian visual arts reveals geometric structures and characteristics that are typical of eye floaters. It is speculated that two central mythological concepts, the sun and the world, are directly or indirectly inspired by the perception of floaters. Key words: eye floaters, entoptic phenomena, phosphenes, visual arts, ancient Egypt, shamanism What are eye floaters? Many people experience mobile and scattered semi- transparent dots and strands in the visual field, best perceived in bright light conditions (See Figure 1). They float according to eye movements, which makes them hard to focus on. People often consult their eye doctors because they are worried by these dots and strands. Usually, the doctors check the patients’ eyes, find nothing to worry about and reassure the patients that these dots and strands are called eye floaters or vitreous floaters, also known as muscae volitantes (Latin: “flying Figure 1: Example of semi- flies”). They are explained as opacities in the gel transparent, mobile dots and strings between the lens and the retina (vitreous humor) due to in the visual field. -
"Visual Prostheses"
530 VISUAL PROSTHESES VISUAL PROSTHESES JEAN DELBEKE CLAUDE VERAART Catholic University of Louvain Brussels, Belgium INTRODUCTION Minute electrical stimuli delivered to the retina, the optic nerve, or the occipital cortex can induce light perceptions called phosphenes. The visual prosthesis aims at exploiting these phosphenes to restore a form of vision in some cases of blindness. Very schematically, a camera or a picture capturing device transforms images into electrical signals that are then adapted and passed on to some still functional part of the visual pathways, thus bridging the defective structures. The system has at least some parts implanted, including electrodes and their stimulator circuits. A photo- sensitive array in the eye could provide the necessary image input, but most approaches use an external minia- ture camera. Typically, the visual data handling requires an external processor and the power supply as well as the data are provided to the implant by a transcutaneous transmission system. Despite a first pioneering attempt by Brindley and Lewin as early as 1968 (1) only very few experimental visual prostheses have been implanted in humans so far. The limited accessibility of the involved anatomical struc- tures, the poorly understood neural encoding, and the huge amount of information handled by the visual nervous system have clearly hampered a development that can not yet be compared with the far more advanced evolution of cochlear implants (see article on Cochlear Implants in this encyclopedia). The visual prosthesis is still at a very Encyclopedia of Medical Devices and Instrumentation, Second Edition, edited by John G. Webster Copyright # 2006 John Wiley & Sons, Inc. -
Acute Visual Loss
425 Acute Visual Loss ShirleyH.Wray,MD,PhD,FRCP1 1 Department of Neurology, Massachusetts General Hospital, Boston, Address for correspondence ShirleyH.Wray,MD,PhD,FRCP, Massachusetts Department of Neurology, Massachusetts General Hospital, 55 Fruit St, Boston 02114, MA (e-mail: [email protected]). Semin Neurol 2016;36:425–432. Abstract Acute visual loss is a frightening experience, a common ophthalmic emergency, and a diagnostic challenge. In this review, the author focusses on the diagnosis of transient Keywords monocular blindness and visual loss due to infarction of the retina and/or the optic nerve ► ocular stroke —the ocular parallel of cerebral stroke. Illustrative Case the left supraclinoid internal carotid artery (ICA) just proximal to the origin of the left posterior communicating artery. Day 1: The patient is a 75-year-old ophthalmologist who Day 22: The patient consulted a neurovascular surgeon experienced an acute transient “white out” of her vision in who obtained a head and neck computed tomographic her left eye lasting for 20 minutes. She had no accompanying angiogram that showed that the ICA aneurysm was symptoms. At this time, the patient was concerned and unchanged in size and morphology from the previous anxious that the white out of vision was an attack of transient exam. No other aneurysm was seen. The surgeon reviewed monocular blindness—a transient ischemic attack that can all the imaging studies with the patient and reassured her herald stroke. that there was minimal risk of rupture of the aneurysm. Day 4: She asked her ophthalmology fellow to examine her eye including intraocular pressure, dilated funduscopy, and Special Explanatory Note automated (Humphrey) visual fields.