IOSR Journal of Dental and Medical Sciences is one of the speciality Journal in Dental Science and Medical Science published by International Organization of Scientific Research (IOSR). The Journal publishes papers of the highest scientific merit and widest possible scope work in all areas related to medical and dental science. The Journal welcome review articles, leading medical and clinical research articles, technical notes, case reports and others.
Purpose: We report a rare case of a 2 - year-old child with ectopia lentis and potential Marfan syndrome (MFS) and discuss her management.
Methods: A 2 - year - old female with no signifi cant past medical history was brought in by her mother after complaints that the child has recently been holding everything close to her eyes while simultaneously shifting her head down. Her mother reported no history of pain or trauma. The child’s family history was negative for ectopia lentis or MFS.
Purpose: We report a rare case of a 2 - year-old child with ectopia lentis and potential Marfan syndrome (MFS) and discuss her management.
Methods: A 2 - year - old female with no signifi cant past medical history was brought in by her mother after complaints that the child has recently been holding everything close to her eyes while simultaneously shifting her head down. Her mother reported no history of pain or trauma. The child’s family history was negative for ectopia lentis or MFS.
- An article describes what is the impact of refractive error on a layer of retina ( nerve fiber layer) in myopic subjects, Download its full text from Isra Medical Journal.
Objective: To evaluate myopic impact on thickness of nerve fiber layer of the retina in healthy myopic subjects.
Study Design: Prospective Observational study.
Place and Duration: Investigative Department of Ophthalmology of Al-Ibrahim Eye Hospital, Karachi from 1st May 2018 to 30th October 2018.
Methodology: In this study 80 eyes of myopic subjects (SE -0.5 to -11.0 DS) were enrolled. Each eye underwent through comprehensive ocular examination beginning with visual acuity, refraction, fundoscopy by slit lamp and ending up to optical coherence tomography of Nidek. Mean average peripapillary thickness of nerve fiber layer and thickness in superior, inferior, nasal and temporal quadrants was taken into consideration, calculated by Spectral Domain Optical Coherence Tomography (version 1.5.5.0).
Results: Forty subjects volunteered for study protocol among which 21 were male and 19 were female with a degree of refractive breakdown of 30% mild myopic, 50% moderately myopic and 20% highly myopic. The calculated average age was 25.0 ± 5.0 years (range 16-40 years). The average total nerve fiber layer thickness in myopic respondents was 90.85μm; superiorly 112.37μm; inferiorly 117.52μm; temporally 71.85μm and in nasal quadrant was 61.55μm. Retinal nerve fiber layer thickness was statistically significant in superior and temporal quadrant. In high myopes thickness was clinically significant in inferior quadrant in terms of quantity as compared to mild and moderate myopia
Conclusion: Average retinal nerve fiber layer thickness was significantly decreased in high myopia as compared to mild myopia while moderate group had slightly thicker thickness than high myopic group. Hence impact of dioptric power on nerve fiber layer thickness in myopic patients is significant.
2012 szudek, dettman et al adults children inner ear malformation adelaideHEARnet _
Bony cochlear or vestibular malformations occur in about 20% of patients with congenital sensorineural hearing loss. Intuitively, one would expect such malformations to influence surgical and audiologic outcomes in patients undergoing cochlear implantation. However, the precise impact of these malformations on surgical and audiologic outcomes has not yet been elucidated.
- An article describes what is the impact of refractive error on a layer of retina ( nerve fiber layer) in myopic subjects, Download its full text from Isra Medical Journal.
Objective: To evaluate myopic impact on thickness of nerve fiber layer of the retina in healthy myopic subjects.
Study Design: Prospective Observational study.
Place and Duration: Investigative Department of Ophthalmology of Al-Ibrahim Eye Hospital, Karachi from 1st May 2018 to 30th October 2018.
Methodology: In this study 80 eyes of myopic subjects (SE -0.5 to -11.0 DS) were enrolled. Each eye underwent through comprehensive ocular examination beginning with visual acuity, refraction, fundoscopy by slit lamp and ending up to optical coherence tomography of Nidek. Mean average peripapillary thickness of nerve fiber layer and thickness in superior, inferior, nasal and temporal quadrants was taken into consideration, calculated by Spectral Domain Optical Coherence Tomography (version 1.5.5.0).
Results: Forty subjects volunteered for study protocol among which 21 were male and 19 were female with a degree of refractive breakdown of 30% mild myopic, 50% moderately myopic and 20% highly myopic. The calculated average age was 25.0 ± 5.0 years (range 16-40 years). The average total nerve fiber layer thickness in myopic respondents was 90.85μm; superiorly 112.37μm; inferiorly 117.52μm; temporally 71.85μm and in nasal quadrant was 61.55μm. Retinal nerve fiber layer thickness was statistically significant in superior and temporal quadrant. In high myopes thickness was clinically significant in inferior quadrant in terms of quantity as compared to mild and moderate myopia
Conclusion: Average retinal nerve fiber layer thickness was significantly decreased in high myopia as compared to mild myopia while moderate group had slightly thicker thickness than high myopic group. Hence impact of dioptric power on nerve fiber layer thickness in myopic patients is significant.
2012 szudek, dettman et al adults children inner ear malformation adelaideHEARnet _
Bony cochlear or vestibular malformations occur in about 20% of patients with congenital sensorineural hearing loss. Intuitively, one would expect such malformations to influence surgical and audiologic outcomes in patients undergoing cochlear implantation. However, the precise impact of these malformations on surgical and audiologic outcomes has not yet been elucidated.
We assessed visual recognition and visual memory in three children with lesions to the visual cortex having occurred in early infancy. We then explored the time course of visual memory impairment in two of them at 2 years and 3.7 years from the initial assessment.
Our findings indicate that processing of degraded perceptions from birth results in impoverished memories. The dynamic interaction between perception and memory during development might modulate the long-term construction of visual representations, resulting in less severe impairment.
Binocular interaction in amblyopia and its clinical feasibilityBABLI SHARMA
BINOCULAR INTERACTION ITS ASSOCIATION WITH AMBLYOPIA
Apart from binocular summation, the two eyes can influence each other in at least three ways.
Pupillary diameter. Light falling in one eye affects the diameter of the pupils in both eyes. One can easily see this by looking at a friend's eye while he or she closes the other: when the other eye is open, the pupil of the first eye is small; when the other eye is closed, the pupil of the first eye is large.
Accommodation and vergence. Accommodation is the state of focus of the eye. If one eye is open and the other closed, and one focuses on something close, the accommodation of the closed eye will become the same as that of the open eye. Moreover, the closed eye will tend to converge to point at the object. Accommodation and convergence are linked by a reflex, so that one evokes the other.
Interocular transfer. The state of adaptation of one eye can have a small effect on the state of light adaptation of the other. Aftereffects induced through one eye can be measured through the other.
Singleness of vision
An Examination of Effectuation Dimension as Financing Practice of Small and M...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Does Goods and Services Tax (GST) Leads to Indian Economic Development?iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Childhood Factors that influence success in later lifeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Emotional Intelligence and Work Performance Relationship: A Study on Sales Pe...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer’s Acceptance of Internet Banking in Dubaiiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study of Employee Satisfaction relating to Job Security & Working Hours amo...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumer Perspectives on Brand Preference: A Choice Based Model Approachiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Student`S Approach towards Social Network Sitesiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Broadcast Management in Nigeria: The systems approach as an imperativeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study on Retailer’s Perception on Soya Products with Special Reference to T...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study Factors Influence on Organisation Citizenship Behaviour in Corporate ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumers’ Behaviour on Sony Xperia: A Case Study on Bangladeshiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Balanced Scorecard on Nonprofit Organizations (Study on Yayasan P...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Public Sector Reforms and Outsourcing Services in Nigeria: An Empirical Evalu...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Media Innovations and its Impact on Brand awareness & Considerationiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer experience in supermarkets and hypermarkets – A comparative studyiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Social Media and Small Businesses: A Combinational Strategic Approach under t...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Secretarial Performance and the Gender Question (A Study of Selected Tertiary...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Implementation of Quality Management principles at Zimbabwe Open University (...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Organizational Conflicts Management In Selected Organizaions In Lagos State, ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
NVBDCP was launched in 2003-2004 . Vector-Borne Disease: Disease that results from an infection transmitted to humans and other animals by blood-feeding arthropods, such as mosquitoes, ticks, and fleas. Examples of vector-borne diseases include Dengue fever, West Nile Virus, Lyme disease, and malaria.
CDSCO and Phamacovigilance {Regulatory body in India}NEHA GUPTA
The Central Drugs Standard Control Organization (CDSCO) is India's national regulatory body for pharmaceuticals and medical devices. Operating under the Directorate General of Health Services, Ministry of Health & Family Welfare, Government of India, the CDSCO is responsible for approving new drugs, conducting clinical trials, setting standards for drugs, controlling the quality of imported drugs, and coordinating the activities of State Drug Control Organizations by providing expert advice.
Pharmacovigilance, on the other hand, is the science and activities related to the detection, assessment, understanding, and prevention of adverse effects or any other drug-related problems. The primary aim of pharmacovigilance is to ensure the safety and efficacy of medicines, thereby protecting public health.
In India, pharmacovigilance activities are monitored by the Pharmacovigilance Programme of India (PvPI), which works closely with CDSCO to collect, analyze, and act upon data regarding adverse drug reactions (ADRs). Together, they play a critical role in ensuring that the benefits of drugs outweigh their risks, maintaining high standards of patient safety, and promoting the rational use of medicines.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Visual Evoked Potential in Normal and Amblyopic Children
1. IOSR Journal of Dental and Medical Sciences (IOSR-JDMS)
e-ISSN: 2279-0853, p-ISSN: 2279-0861.Volume 14, Issue 11 Ver. VII (Nov. 2015), PP 01-07
www.iosrjournals.org
DOI: 10.9790/0853-141160107 www.iosrjournals.org 1 | Page
Visual Evoked Potential in Normal and Amblyopic Children
Kiran Kumar Patnaik1
, Ajay Shankar Kar2
(1)
Assistant Professor, Department of Physiology, Maharajah’s institute of Medical Sciences, Nellimarla,
Vizianagaram, Andhra Pradesh.
(2)
Consultant Ophthalmologist, Seven Hills Hospital, Visakhapatnam.
Abstract:
Background: Amblyopia refers to a decrease in best-corrected visual acuity in an eye having no organic
pathology. Amblyopia is primarily a cortical phenomenon, caused by unequal competitive inputs from the two
eyes into primary visual cortex area 17, although additional structural and functional abnormalities have been
observed in the lateral geniculate nucleus of amblyopic animals and human. It has been estimated to affect 1–
3% of the population Amblyopia usually affects only one eye, but it is possible to be amblyopic in both eyes if
both are similarly deprived of a good, clear visual image. Detecting the condition in early childhood increases
the chance of successful treatment.
I. Objective
1. Recording of VEP in normal individuals.
2. Recording of VEP in Ambylopia individuals.
3. Comparison of the results of the above two groups.
II. Materials and Methods
52 Amblyopic children in the age group of 4-12 years belonging to both sexes were studied. Age and
sex matched control group of 52 normal children were also studied.(Due criteria were adopted for inclusion and
exclusion)Pattern Visual Evoked Potential (PVEP) were recorded on Viking Select neuro diagnostic system.
III. Results
In PVEP , P100 latencies were longer and amplitudes were shorter in amblyopic group compared to
normal group. The data was subjected to various statistical analysis using SPSS-21 software. The difference in
latencies and amplitudes between two groups (amblyopic & normal) was statistically significant when the data
was subjected to the independent samples T test.
IV. Conclusion
P100 latency of PVEP at the time of presentation was significantly related to visual acuity. So PVEP test
may be useful in future to identify amblyopia long before the appearance of symptoms and to follow treatment
progress in pediatric amblyopes.
Keywords- Visual Evoked Potential (VEP), Amblyopia
V. Background
The term amblyopia describes a condition in which there is reduced visual function in one, or
infrequently both, eye(s), despite optimum optical correction and the absence of overt pathology of the visual
system. There is an acquired defect in vision that is due to an abnormal visual experience during a sensitive
period of visual development. The neural basis of amblyopia is the study of the effects of the abnormal
environmental influences on the genetically programmed development of visual processing system. The
prevalence of amblyopia in humans is thought to be around 1% to 3%. Human amblyopes are usually
asymptomatic when viewing with both eyes open, as the vision in the fellow eye is generally normal. The
motivation for research is not necessarily to find a treatment for this generally asymptomatic condition but
rather the realization that amblyopia may provide valuable insight into the role of early experience on the
structure and function of the human brain.[1]
Several studies have been performed with electrophysiological methods used in humans and in animal
models, to investigate the retinal and visual system in amblyopia dysfunction. Reported findings regarding
retinal function are contradictory. The function of the entire visual pathway, from photoreceptors to the visual
cortex, can be evaluated by visual evoked potential (VEP) recordings and the presence of abnormal VEP
responses has been observed in amblyopia.[2]
2. Visual Evoked Potential in Normal and Amblyopic Children
DOI: 10.9790/0853-141160107 www.iosrjournals.org 2 | Page
As the VEP readings assess the bioelectrical response of the visual cortex, the observations derived from
previous studies do not suggest specific information on whether the reported VEP abnormalities may be
selectively related to a retinal dysfunction, a postretinal dysfunction, or both. That postretinal structures, in
particular the lateral geniculate nucleus (LGN), may be involved in amblyopia dysfunctional processes was first
suggested by Hubel and Wiessel and later documented in several studies in which morphologic and functional
changes of the LGN were detected.[3]
Understanding Evoked Potentials- An evoked potential (or "evoked response") is an electrical potential
recorded from the nervous system of a human or other animal following presentation of a stimulus, as distinct
from spontaneous potentials detected by electroencephalography (EEG) or electromyography (EMG). Evoked
potential amplitudes tend to be low, ranging from less than a microvolt to several micro volts, compared to tens
of micro volts for EEG, mill volts for EMG, and often close to a volt for ECG. To resolve these low-amplitude
potentials against the background of ongoing EEG, ECG, EMG and other biological signals and ambient noise,
signal averaging is usually required. The signal is time-locked to the stimulus and most of the noise occurs
randomly, allowing the noise to be averaged out with averaging of repeated responses.[4]
Signals can be recorded from cerebral cortex, brain stem, spinal cord and peripheral nerves. Usually the term
"evoked potential" is reserved for responses involving either recording from, or stimulation of, central
nervous system structures. Sensory evoked potentials (SEP) are recorded from the central nervous system
following stimulation of sense organs (for example, visual evoked potentials elicited by a flashing light or
changing pattern on a monitor; auditory evoked potentials by a click or tone stimulus presented through
earphones) or by tactile or somatosensory evoked potential (SSEP) elicited by tactile or electrical stimulation of
a sensory or mixed nerve in the periphery. They have been widely used in clinical diagnostic medicine since the
1970s, and also in intraoperative neurophysiology monitoring (IONM), also known as surgical neurophysiology.
Neuroanatomical and Neurophysiological Abnormalities in Amblyopia
Foveal vision in amblyopia resembles peripheral vision in normals. This suggests that inappropriately
large receptor fields (spatial summation) have developed in the foveal visual cortex. This hypothesis would
explain the loss of contrast sensitivity at high spatial frequencies with preservation of low spatial frequencies.
The phenomenon of spatial uncertainty, defects in judging line offset effects (vernier acuity) and the altered
psyhovisual performance when tested with crowded targets.
Amblyogenic Mechanisms - Disuse versus Competition
Two amblyogenic mechanisms have been proposedand that these may be effective, individually or, in
unison, in the various forms of amblyopia. [5,6]
Disuse - A lack of adequate retinal stimulation during infancy,
causing visual deprivation with arrest of development at a stage at which the interference began, or disuse
atrophy of afferent connections that were already present at birth. This is not regarded as being a major factor in
the development of strabismic amblyopia is now being disputed. Since the salient feature of strabismic
amblyopia is not the lack of afference but the incompatibility of visual impressions received by both eyes.
Competition- This is based on the view that stimulation of corresponding retinal points with unequal
images causes rivalry between the two eyes which is decided in favour of the fixating eye, the other eye
becoming amblyopic. Binocular deprivation and strabismus experiments support that competition rather than
disuse is the main cause of the observed changes. The right circumstances must exist, however, for the
competition to occur, since cells in the normal visual cortex tend to be dominated by one eye or the other, and
the dominant eye does not take over the cell completely. It appears that the incompatibility of the visual input
received by the two eyes causes a decrease or even blockage of synaptic transmission of the afferent impulses
originating from the nonfixing eye
VI. Materials And Methods
Subjects- 52 amblyopic patients of different etiologies were selected for the study. The patients who
were not treated earlier for refractive error, amblyopia or ocular disease were considered for study. Clear media
and normal fundus on ophthalmoscopic examination was a prerequisite for selection criteria.
The 52 patients, based on the etiologies are divided as:
Strabismic- 11
Anisometropic- 16
Isometropic- 25
1.Age group: 4-13 years
2.Sex distribution: Out of 52 patients 32 were female and 20 were male children.
3.Type of study: Prospective study
4.Inclusion criteria: All the children with amblyopia above three years of age were included in the study group.
5.Exclusion criteria: Children below three years
3. Visual Evoked Potential in Normal and Amblyopic Children
DOI: 10.9790/0853-141160107 www.iosrjournals.org 3 | Page
-Non co-operative children
-Toxic Amblyopia
6. Place of Study: Study was conducted in the Dept of Ophthalmology, Seven Hills Hospital, Visakhapatnam,
Andhra Pradesh.
7. History: A full and detailed history regarding the onset of defective vision, squint, duration of symptoms,
associated symptoms and previous treatment history was taken. Consent of the subjects and their parents were
taken prior to the examination. Ethical committee approval was taken prior to the study.
8.Visual acuity: The base level visual acuity was tested with Snellen’s visual acuity charts, Optotype charts for
both distance and near, without and with correction of refractive error were estimated monocular and
binocularly.
9.52 age and sex matched controls were taken as a comparative group, out of which 33 were males and 19 were
females.
20. VEPs were recorded in both the groups.
VEP (VISUAL EVOKED POTENTIALS)
Equipment- Nicolet Viking Select Neuro-diagnostic system version 10.0 was used to record visually
evoked potentials.
Stimulus type: Pattern reversal visual evoked potential Stimuli are delivered through the Nicolet 2015
Visual Stimulator monocularly and the pattern stimuli were displayed on a color monitor.
Parameters: Distance- 100 cm, Visual angle-0˚54’, Frequence-1.1HZ, Filters-1-100 HZ,
Sweeps -100.
Recording Technique -The patient is made to sit at a distance of 100 cm from a TV monitor which
displays the checkerboard pattern. The preferred stimulus for clinical investigation of the visual pathways is a
shift (reversal) of a checkerboard pattern (usually black and white). The squares simply reverse without change
in total light output (luminance) from the screen. Patient is asked to fix his/her vision at a point in the center of
the pattern field and view it with a single eye. (Monocular testing) Light-tight opaque patch to be placed over
the unstimulated eye. Care was taken to have the patient in a comfortable, well-supported position to minimize
artifacts especially noise. A minimum of two recordings of each VEP condition were acquired, measured and
displayed to confirm reproducibility of the data.
Reproducibility - reliability –
Various studies show that P100 component of PSVEP is more consistent and reliable and shows
reproducibility better than any other wave components of various long latency EPs and is less affected by
attention and concentration. However, the examiner must observe the gaze direction, whether it is directed
towards the center, whether the eyes are close or open etc. as these effect the amplitude.
Latencies recordings are at N75, P100 and at N145.
Amplitudes recorded atN75-P100 and N 100 -P145.
Analysis: Evaluation and interpretation of VEP changes were done in the two groups based on the data
recorded.
Statistical analyses:Analyses were performed using SPSS version 21.0 (PASW Statistics) for Windows. (SPSS,
Inc., Chicago, IL).The data of both amblyopic group and control group were subjected to the following
statistical analysis- Descriptive Statistics and Independent Samples T- Test.
Descriptive Statistics in Amblyopia
N Range Minimu
m
Maximu
m
Mean Std.
Deviation
Skewness Kurtosis
Statisti
c
Statistic Statistic Statistic Statisti
c
Statistic Statistic Std.
Error
Statistic Std.
Error
Age 52 8.0 4.0 12.0 8.058 1.9844 .089 .330 -.441 .650
VEPN75REP 52 31 61 92 74.23 6.676 .701 .330 .324 .650
VEPP100REP 52 59 87 146 115.50 13.457 .217 .330 -.533 .650
VEPN145RE
P
52 57 133 190 151.69 12.298 1.484 .330 2.495 .650
N75P100REP 52 16 2 18 5.30 3.399 1.880 .330 3.904 .650
VEPN75LEP 52 73 42 115 74.44 10.357 .709 .330 4.788 .650
VEPP100LEP 52 56 85 141 115.06 11.770 .118 .330 -.015 .650
VEPN145LE
P
52 74 126 200 153.88 13.886 1.452 .330 3.683 .650
VN75P100LE
P
52 21 2 23 5.59 3.743 2.675 .330 9.270 .650
Valid N
(listwise)
52
(VEP- Visual evoked potential, N75- first negative wave at 75th
milli sec, P100- first positive at 100th
milli sec,
N145 – second negative wave at 145th
milli seconds. RE- Right eye,LE- Left eye, P- Patient.
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Descriptive Statistics Control
N Range Minimu
m
Maximu
m
Mean Std.
Deviation
Skewness Kurtosis
Statistic Statistic Statistic Statistic Statistic Statistic Statistic Std.
Error
Statistic Std.
Error
CAge 30 6.0 6.0 12.0 8.867 1.7167 -.130 .427 -.898 .833
VEPN75REC 52 29 58 87 71.65 6.312 -.067 .330 -.426 .650
VEPP100REC 52 15 89 104 98.19 3.726 -.706 .330 -.155 .650
VEPN145RE
C
52 46 104 150 137.62 7.217 -1.725 .330 8.131 .650
N75P100REC 52 17 1 18 11.82 3.367 -.998 .330 2.261 .650
VEPN75LEC 52 32 57 89 72.60 6.669 .054 .330 -.087 .650
VEPP100LEC 52 12 93 105 99.10 3.471 -.324 .330 -.954 .650
VEPN145LE
C
52 20 130 150 138.83 5.684 .568 .330 -.667 .650
N75P100LEC 52 13 6 19 11.18 3.066 .847 .330 .796 .650
Valid N
(listwise)
30
(VEP- Visual evoked potential, N75- first negative wave at 75th
milli sec, P100- first positive at 100th
milli sec,
N145 – second negative wave at 145th
milli seconds. RE- Right eye,LE- Left eye, C- control)
Sex
Frequency Percent Valid Percent
Cumulative
Percent
Valid Male 53 51.0 51.0 51.0
Female 51 49.0 49.0 100.0
Total 104 100.0 100.0
0
20
40
60
80
100
120
140
160
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53
P100LATENCYINMILLISEC
NO OF INDIVIDUALS
P100 LATENCY OF RE CASES Vs CONTROL
AMBLYOPIA CONTROL
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0
20
40
60
80
100
120
140
160
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53
P100Latencyinmsec
No of individuals
P100 LATENCY OF LE CASES Vs CONTROL
AMBLYOPIA CONTROL
0
5
10
15
20
25
30
35
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
AMPLITUDEINMICROVOLTS
N75-P100 Amplitude of Right Eye Cases Vs Control
AMBLYOPIA CONTROL
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VII. Results
VEPs
1. The mean age of non-amblyopic group is 8.867+/-1.716 (33 males,19 females).The mean age of
amblyopic group is 8.058+/-1.984 (20 males,32 females).
2. The mean value of latencies in milliseconds in right side in non-amblyopic group -N75 is 71.65+/-
6.312, P100 is 98.19+/-3.726 and N145 is 137.62 +/-7.217 where as in amblyopics N75 is 74.23+/-
6.676, P100 is 115.50+/-13.457 and N145 is 151.69 +/-12.298.
3. The mean value of amplitudes(in microvolts)for right side in non-amblyopics include N75-P100 is
11.82+/-3.367 where as in amblyopics N75-P100 is 5.30+/-3.399.
4. The mean value of latencies in milliseconds in left side in non-amblyopic group N75 is 72.60+/-6.669,
P100 is 99.10+/-3.471 and N145 is 138.83+/-5.648,where as in amblyopics N75 is 74.44+/-10.357,
P100 is 115,06+/-11.77 and N145 is 153.88+/-13.88.
5. The mean value of amplitudes(in microvolts)for left side in non-amblyopics include N75-P100 is
11.306+/-3.747,where as in amblyopics N75-P100 is 5.59+/-3.743.
Independent Samples T Test shows statistically significant variations in P100 latencies of right side (p=0.016)
when amblyopes were compared with age matched controls.While similar analysis between left side P100
latencies was not statistically significant. The N75-P100 amplitude (in microvolts) was statistically significant
(p=0.012) in right side when age matched amblyopes were compared with controls. The N75-P100 amplitude in
the left eyes were not statistically significant,
VIII. Discussion
The response of visual cortex to patterned repetitive visual stimuli was tested in normal and amblyopic
children, The VEP latencies and amplitudes were compared between normal and amblyopic children. A
significant correlation was established in VEP P100 latencies and VEP N75-P100 amplitudes between normal
and amblyopia groups. The P100 latency was significantly prolonged (statistically significant,p˂0.05) and there
was a significant decrease in N75-P100 amplitude(p˂0.05) in amblyopic group which is in accordance to
previous studies.[7,8]
There were no differences in other VEP parameters ( N75, N145 ) between the two groups.
In current study, the right eye of the amblyopic group showed more correlation than left. This may provide some
information regarding specialization of functions in cerebral hemispheres. As all the patients examined
happened to be right handed i.e left hemi sphere dominance (motor activities, speech etc.) it may be coupled
with localization of some functions in left hemisphere related to cognitive process.[9]
VEP P100is a long latency
evoked potential. P-100 response of the visual evoked potential to pattern stimulation is a cortically originated
wave either produced exclusively by area 17 or 18 or by a multiplicity of cortical neuronal pools.[10]
Prolongation
of P100 latency in our study, strongly suggest an abnormality at cortical level in amblyopia which is consistent
with previous studies.[11,12]
Also right sided P100 latencies more significant than left side suggesting,
impairment of some cognitive function localized to left hemisphere based on impairment of processing of visual
information
0
5
10
15
20
25
30
35
40
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51
AMPLITUDEINMICROVOLTS
N75-P100 Amplitude of Left Eye CasesVs Control
AMBLYOPIA CONTROL
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DOI: 10.9790/0853-141160107 www.iosrjournals.org 7 | Page
IX. Conclusion
VEP is a long latency evoked potential and P100 is a more reliable signal for processing information at
cortical level. P100 latencies are prolonged and amplitudes are reduced in amblyopic group. P100 latency of
PVEP at the time of presentation was significantly related to visual acuity. So PVEP test may be useful in future
to identify amblyopia long before the appearance of symptoms and to follow treatment progress in pediatric
amblyopes,[13,14]
Further investigation is needed to determine whether these results are due to physiologic
change(s) of amblyopia itself or to fixation in stability during the test.
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