Direct Download Link ❤❤https://healthkura.com/eye-ppt/28/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com/eye-ppt/❤❤❤
anatomy of optic nerve and its blood supply and clinical corelation
Presentation Layout: optic nerve anatomy
Embryology of optic nerve
Introduction
Parts of optic nerve
Blood supply
Clinical significance
For Further Reading
Wolff’s Anatomy of the eye and orbit by Bron, Tripathi and Tripathi
Anatomy and Physiology of eye by A.K. Khurana 2nd edition
Comprehensive Ophthalmology by A.K. Khurana 5th edition
AAO- Fundamentals & Principles of Ophthalmology : sec 2
Walsh and Hoyt’s Clinical Ophthalmology
Internet
1-IT IS A MIDDLE VASCULAR COAT OF EYEBALL.
2-IT MAINLY CONSIST OF THREE PARTS IRIS, CHOROID, CILIARY BODY.
3- CILIARY BODY CAN HOLD THE LENS AND PLAY IMPORTANT ROLE IN ACCOMODATION.
This presentation gives a brief idea about angle of anterior chamber along with its structures and diagnostic methods to grade and visualize the structures.
1-IT IS A MIDDLE VASCULAR COAT OF EYEBALL.
2-IT MAINLY CONSIST OF THREE PARTS IRIS, CHOROID, CILIARY BODY.
3- CILIARY BODY CAN HOLD THE LENS AND PLAY IMPORTANT ROLE IN ACCOMODATION.
This presentation gives a brief idea about angle of anterior chamber along with its structures and diagnostic methods to grade and visualize the structures.
Passive Therapy in Management of Amblyopia (healthkura.com)Bikash Sapkota
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/lazy-eye-amblyopia/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤
Passive Therapy in Management of Amblyopia
. Passive Therapy
The patient experiences a change in visual stimulation without any conscious effort
- Proper refractive correction
- Occlusion
- Penalization
Active Vision Therapy in Management of Amblyopia (healthkura.com)Bikash Sapkota
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/lazy-eye-amblyopia/❤❤
In the request of my viewers, I have compiled my works here in a website. Visit this website (healthkura.com) to freely download this presentation along with other tons of presentations. Some useful links are given here.____Remember___healthkura.com
Active Vision Therapy in Management of Amblyopia
- Pleoptics
- Near activities
- Active stimulation therapy using CAM vision stimulator
- Syntonic phototherapy
- Role of perceptual learning
- Binocular stimulation
- Software-based active treatments
- Exposure to dark
- Pharmacological Therapy
Interventions to Reduce Myopia Progression in Children (Journal Club) (health...Bikash Sapkota
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/reduce-myopia/❤❤
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Interventions to Reduce Myopia Progression in Children (Journal Club)
Objectives:
- To discuss about the different interventions to reduce myopia progression in children
- To determine the effectiveness of different interventions to slow down the progression of myopia in children
Interventions to Reduce Myopia Progression:
Environmental Considerations
- Time Spent Outdoors
- Near-Vision Activities
Spectacles & Contact Lenses
- Gas-Permeable Contact Lens Wear
- Bifocal & Multifocal Spectacles
- Soft Bifocal Contact Lenses
- Orthokeratology
Pharmacological Therapies
- Antimuscarinic Agents: Atropine & Pirenzepine
Under Correction of Myopia
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Data Collection (Methods/ Tools/ Techniques), Primary & Secondary Data, Assessment of Qualitative Data, Qualitative & Quantitative Data, Data Processing
Presentation Contents:
- Introduction to data
- Classification of data
- Collection of data
- Methods of data collection
- Assessment of qualitative data
- Processing of data
- Editing
- Coding
- Tabulation
- Graphical representation
If anyone is really interested about research related topics particularly on data collection, this presentation will be the best reference.
For Further Reading
- Biostatistics by Prem P. Panta
- Fundamentals of Research Methodology and Statistics by Yogesh k. Singh
- Research Design by J. W. Creswell
- Internet
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/vision-therapy/❤❤
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Vision Training/ Vision Therapy (Active/ Passive Vision Therapy)/ Sports Vision/ Computer Vision Syndrome
Contents:
-Vision Training
Overview
Misconception
Tips for success
Office Vision Training
Home Vision Training
Conditions treated by vision training
Sports Vision Training
Computer Vision Syndrome
Controversy
Summary
Summary
• Vision training is active therapy as it requires conscious participation by the pt.
• The achievement of the final goal occurs slowly and progressively
• VT is not a substitute to lenses or surgical therapy, it is an additional treatment
• Variety of BSV related conditions can be treated with VT
• The underlying neuropsychophysiological mechanisms affected by VT are still
under intense investigation
• VT is the most controversial subject in eyecare profession
Current Trend in Management of Amblyopia (Amblyopia Therapy)/ Amblyopia Treat...Bikash Sapkota
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/lazy-eye-amblyopia/❤❤
Dear viewers, to download this presentation visit___ https://healthkura.com/lazy-eye-amblyopia/
Current Trend in Management of Amblyopia. Latest as well as old methods of amblyopia management which include active and passive therapies. Amblyopia Therapy/ Amblyopia Treatment
What would be the perfect amblyopia therapy?
Effective
Good compliance
Acceptable to pts. and parent
Quick
Safe
Easy to administer
Cost effective
Well maintained
..............
Summary
Amblyopia occurs due to abnormal visual experience early in life
Proper optical correction alone is necessary for short period of time (6-8 weeks)
before initiation of other therapy
Part time occlusion of better eye is mainstay of treatment since 18th century to till
now
For severe and moderate amblyopia, 6 hrs and 2 hrs of patching is advised
respectively
Atropine is also used in children with poor compliance
Trial of patching can be given in patients as old as 17 yrs
Perceptual learning and pharmacological manipulation have shown areas of
amblyopia treatment beyond the critical period of visual development
Binocular stimulation, software based treatments and other methods do not have
promising result to replace the patching therapy till date
Most of the active therapy methods have good results when used together with
patching therapy
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/ocular-ultrasound/❤❤
Dear viewers Check Out my other piece of works at___ https://healthkura.com
Ocular Ultrasonography (Ocular USG/ Ophthalmic USG), ophthalmic ultrasound/ ophthalmic ultrasonography/ ocular ultrasound/ Ultrasound of eye and orbit
PRESENTATION LAYOUT
Introduction
History
Physics
Principles & instrumentation
Terminologies
Indications & contraindications
Methods - A-Scan - B-Scan
Interpretation
Definition
Ultrasound Waves are acoustic waves that have frequencies greater than 20 KHz
The human ear can respond to an audible frequency range, roughly 20 Hz - 20 kHz
......................
For Further Reading
Clinical Procedures in Optometry by J. D. Barlett, J. B. Eskridge & J. F. Amos
Ophthalmic Ultrasound: A Diagnostic Atlas by C. W. DiBernardo & E. F. Greenberg Internet
Accommodation/ Accommodation of Eye, Measurement of Accommodation of Eye (hea...Bikash Sapkota
CLICK HERE TO DOWNLOAD FULL PPT ❤❤ https://healthkura.com/measurement-of-accommodation-of-eye/ ❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤❤
Measurement of Accommodation of eye:
Amplitude, Facility,
Relative Accommodation, Fatigue, Lag,
Dynamic Retinoscopy
Presentation Layout:
-Introduction to accommodation of eye
-Mechanism
-Components
-Measurement of accommodation of eye
- Amplitude
- Facility
- Relative accommodation
- Lag
-Dynamic Retinoscopy
Accommodation
-dioptric adjustment of the crystalline lens of the eye
- to obtain clear vision for a given target of regard
-process by which the refractive power of eye is altered
- to ensure a clear retinal image
For further reading
-Clinical Procedures in Optometry by J.D. Bartlett, J.B. Eskridge, J.F. Amos
-Primary Care Optometry by Theodere Grosvenor
-Borish’s Clinical Refraction by W.J. Benjamin
-Clinical Procedures for Ocular examination by Carlson et al
-American Academy of Ophthalmology
-Optometric Clinical Practice Guideline by American Optometric Association
-Internet
Follow me to get in touch with optometric and ophthalmic updates
Presbyopia/ Methods of Presbyopic Addition Determination (healthkura.com)Bikash Sapkota
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/presbyopia-near-addition/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤❤
Presbyopia and techniques of measurement
A fantastic presentation in the topic "Presbyopia and techniques of measurement"
A detailed information about presbyopia, techniques of presbyopic add determination and different correction methods.
Informative slide presentation on presbyopia for ophthalmology residents, ophthalmologists, optometrists, ophthalmic assistants, ophthalmic technicians, ophthalmic nurses, medical students, medical professors, teaching guides.
Presentation Contents:
--Introduction to presbyopia
-Types of presbyopia
-Risk factors
-Symptoms and signs
-Refractive error and presbyopia
-Methods of determining near add.
-Management of presbyopia
In a nutshell..
- The evaluation and management of presbyopia are important because significant functional deficits can occur when the condition is left untreated
- Undercorrected or uncorrected presbyopia can cause significant visual disability and have a negative impact on the pt.'s quality of life
- Finally, every tentative addition should be adjusted according to the particular needs of the patient
For Further Reading:
-Clinical Procedures in Optometry by J.D. Bartlett, J.B. Eskridge, J.F. Amos
-Primary Care Optometry by Theodere Grosvenor
-Borish’s Clinical Refraction by W.J. Benjamin
-Clinical Procedures for Ocular examination by Carlson et al
-American Academy of Ophthalmology
-Optometric Clinical Practice Guideline by American Optometric Association
-Internet
Follow me to get in touch with optometric and ophthalmic updates.
DIRECT DOWNLOAD LINK ❤❤https://healthkura.com/retinoscopy/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤❤
Retinoscopy and Objective Refraction and Subjective Refraction in spherical ametropia and astigmatism
Retinoscopy (Principle & Techniques of Retinoscopy) and objective refraction, Subjective Refracition
Best presentation about retinoscopy and objective refraction techniques, and basis of subjective refraction. If you want to master the technique of retinoscopy, this presentation can be your guidance and partner in your journey to retinoscopy, objective refraction and subjective refraction.
Presentation Layout:
Retinoscope, types of retinoscope and uses of retinoscope
-Introduction to retinoscopy and objective refraction
-Retinoscopy
- In spherical ametropia
- In astigmatism
- Others: strabismus, amblyopia, pediatric pt.,
cycloplegic refraction
-Static and Dynamic Retinoscopy
-Problems seeing reflex during retinoscopy
-Errors in retinoscopy
Objective of retinoscopy and objective refraction
-To locate the far point of the eye conjugate to the retina
- Myopia or hyperopia
-Bring far point to the infinity by using appropriate lenses
- Determines amount of ametropia by retinoscopy and objective refraction
References:
-Clinical Procedures in Optometry by Eskridge, Amos and Bartlett ,
-Primary Care Optometry by Grosvenor T.,
-Borish’s Clinical Refraction by Benjamin W. J.,
-Theory And Practice Of Optics And Refraction by AK Khurana
-Retinoscopy-Student Manual by ICEE Refractive Error Training Package (2009)
-Clinical Optics and Refraction By Andrew Keirl, Caroline Christie
-Clinical Refraction Guide - A Kumar Bhootra
-Clinical Procedures in Primary Eye Care by David B. Elliott
-Internet
Follow me to get in touch with optometric and ophthalmic updates.
Direct Download Link ❤❤https://healthkura.com/antibacterial-agents/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com ❤❤❤
Antibacterial Agents/ antibiotics (Ocular Pharmacology)
PRESENTATION LAYOUT
Introduction to antimicrobial drugs
Classification of antimicrobial drugs
Antibacterial drugs:
- Classification
- Indications
- Side effects
Antibacterial Resistance
Antimicrobial drugs are chemotherapeutic drugs
Two categories: – Antibiotics : Antimicrobial drugs produced by microorganisms
– Synthetic drugs : Antimicrobial drugs synthesized in the lab
..............................................
For Further Reading
oTextbook of microbiology by Ananthanarayan & Paniker
o Essentials of Medical Pharmacology KD Tripathi
o Basic & Clinical Pharmacology by Bertram G. Katzung
o Ophthalmic Drugs by Graham Hopkins and Richard Pearson
o Internet
Polarization of Light and its Application (healthkura.com)Bikash Sapkota
Download link ❤❤https://healthkura.com/eye-ppt/29/❤❤
Dear viewers Check Out my other piece of works at ❤❤❤ https://healthkura.com/eye-ppt/ ❤❤❤
polarization of light & its application.
PRESENTATION LAYOUT
Concept of Polarization
Types of Polarization
Methods of achieving Polarization
Applications of Polarization
POLARIZATION
Transforming unpolarized light into polarized light
Restriction of electric field vector E in a particular plane so that vibration occurs in a single plane
Characteristic of transverse wave
Longitudinal waves can’t be polarized; direction of their oscillation is along the direction of propagation.............
For Further Reading
•Optics by Tunnacliffe
•Optics and Refraction by A.K. Khurana
•Principle of Physics, Ayam Publication
•Internet
Prix Galien International 2024 Forum ProgramLevi Shapiro
June 20, 2024, Prix Galien International and Jerusalem Ethics Forum in ROME. Detailed agenda including panels:
- ADVANCES IN CARDIOLOGY: A NEW PARADIGM IS COMING
- WOMEN’S HEALTH: FERTILITY PRESERVATION
- WHAT’S NEW IN THE TREATMENT OF INFECTIOUS,
ONCOLOGICAL AND INFLAMMATORY SKIN DISEASES?
- ARTIFICIAL INTELLIGENCE AND ETHICS
- GENE THERAPY
- BEYOND BORDERS: GLOBAL INITIATIVES FOR DEMOCRATIZING LIFE SCIENCE TECHNOLOGIES AND PROMOTING ACCESS TO HEALTHCARE
- ETHICAL CHALLENGES IN LIFE SCIENCES
- Prix Galien International Awards Ceremony
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
Follow us on: Pinterest
Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
MANAGEMENT OF ATRIOVENTRICULAR CONDUCTION BLOCK.pdfJim Jacob Roy
Cardiac conduction defects can occur due to various causes.
Atrioventricular conduction blocks ( AV blocks ) are classified into 3 types.
This document describes the acute management of AV block.
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
Flu Vaccine Alert in Bangalore Karnatakaaddon Scans
As flu season approaches, health officials in Bangalore, Karnataka, are urging residents to get their flu vaccinations. The seasonal flu, while common, can lead to severe health complications, particularly for vulnerable populations such as young children, the elderly, and those with underlying health conditions.
Dr. Vidisha Kumari, a leading epidemiologist in Bangalore, emphasizes the importance of getting vaccinated. "The flu vaccine is our best defense against the influenza virus. It not only protects individuals but also helps prevent the spread of the virus in our communities," he says.
This year, the flu season is expected to coincide with a potential increase in other respiratory illnesses. The Karnataka Health Department has launched an awareness campaign highlighting the significance of flu vaccinations. They have set up multiple vaccination centers across Bangalore, making it convenient for residents to receive their shots.
To encourage widespread vaccination, the government is also collaborating with local schools, workplaces, and community centers to facilitate vaccination drives. Special attention is being given to ensuring that the vaccine is accessible to all, including marginalized communities who may have limited access to healthcare.
Residents are reminded that the flu vaccine is safe and effective. Common side effects are mild and may include soreness at the injection site, mild fever, or muscle aches. These side effects are generally short-lived and far less severe than the flu itself.
Healthcare providers are also stressing the importance of continuing COVID-19 precautions. Wearing masks, practicing good hand hygiene, and maintaining social distancing are still crucial, especially in crowded places.
Protect yourself and your loved ones by getting vaccinated. Together, we can help keep Bangalore healthy and safe this flu season. For more information on vaccination centers and schedules, residents can visit the Karnataka Health Department’s official website or follow their social media pages.
Stay informed, stay safe, and get your flu shot today!
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
3. 3rd week of gestation: the first evidence of primitive
eye formation occurs
Neural plate destined to form
prosencephalon
Optic sulcus formation
depression
Formation of optic vesicle and optic stalk
Embryology
4. Optic stalk is the original connection between the
optic vesicle & the forebrain
Optic sulcus deepens & the walls of
prosencephalon bulge out
Optic vesicle formation
Proximal part of optic vesicle become
constricted & elongated
Optic stalk formation
4th week
5. Embryology of Optic Nerve
Develops in the frame work of optic stalk
Optic Nerve Head
Formed as the optic stalk encloses the hyaloid
artery (the 8th week)
From the hyaloid artery, the vascular bud
develops within Bergmeister’s papilla
Hyaloid artery disappears before birth
Bergmeister’s papilla becomes atrophic & the
physiologic cup develops (at 15th week)
6. Optic Nerve
Axons
Develops from the embryonic optic stalk
Stalk lumen is progressively occupied by the
axons growing from the ganglion cells (the 7th
week)
Axons fully occupy the stalk, reach the brain and
a rudimentary optic chaism is formed (the 8th
week)
Myelination starts near chaism and stops at
lamina cribrosa
7. Optic nerve sheaths:
Glial element:
Ѻ Develops from the neuroectodermal cells
forming the outer wall of the optic stalk
Ѻ Differentiates into astrocytes and oligodendrocyte
Ѻ Form from the mesenchymal cells
Ѻ Begin to appear at the end of the 7th week
8. Vasculature
Ѻ Development of capillaries in the optic nerve
and the CNS is similar
Ѻ Vessels and connective tissue from the pia mater
begin to enter the proximal optic nerve (at the
11th week)
Ѻ Capillaries are separated by astrocyte sheet and
perivascular space
Ѻ Vascularization is completed in the 18th week
9. Glimpse of Embryology of Optic Nerve
Weeks of Gestation Length (mm) Developing Events
4 2.5-6 mm Short optic stalk
5 5-9 mm Development of
hyaloid vasculature
6 8- 14 mm Embryonic cleft closes
7 13-18 mm Growth of axons
Formation of optic
nerve
8 18-31 mm Stalk fully occupied by
axons
Axons of optic nerves
reach the brain
Rudimentary optic
chiasm established
Optic nerve
vascularization starts to
form
10. Week of Gestation Length (mm) Developing Events
11 65-73 mm Vascular-connective
septa invade the nerve
12 80 mm Pia mater, arachnoid &
dura mater
distinguishable
Glial filaments appear
14 105 mm Subarachnoid space
appears
15 117-123 mm Physiologic cup starts to
form
18 160 mm Vascularization of the
optic nerve completed
23 220 mm Myelinization starts
Contd……
11. 2nd cranial nerve
Starts from optic disc, extends upto optic
chiasma
Backward continuation of nerve fiber layer of
retina (axons of ganglion cells)
Also contains afferent fibers of light reflex and
some centrifugal fibers
Optic Nerve
12. • An outgrowth of brain
• Not covered by neurilemma: does not regenerate
when cut
• Fibers of optic nerve are very fine (2-10 µm in
diameter ) & are millions in number
• Surrounded by meninges unlike other peripheral
nerves
• Both primary & secondary neurons are in retina
Morphologically and embryologically, the optic
nerve is comparable to a sensory tract of brain
(white matter)
13. About 47-50 mm in length
Divided into 4 parts:
Intraocular (1 mm)
Intraorbital (30 mm)
Intracanalicular (6-9 mm)
Intracranial (10 mm)
Optic
Nerve
Parts of Optic Nerve
14. Intraocular Part
Intraocular Part
SNFL Prelaminar Lamina Cribrosa Retrolaminar
Passes through sclera, choroid & appears in eye as
optic disc
1.5 mm in diameter
Expands to 3 mm behind sclera due to presence of
myelin sheath
Divided into 4 portions (from anterior to posterior):
15.
16. Surface Nerve Fiber Layer
Composed of axonal bundles (94% nerve fibers of
retina + 5% astrocytes)
Optic disc is covered by thin layer of astrocytes,
ILM of Elschnig: separates it from vitreous
When central portion of membrane gets
thickened: Central meniscus of Kuhnt
Near the optic nerve, all layers of retina (except
NFL) are separated from it by: Intermediate tissue
of Kuhnt
17. Prelaminar Region
Predominant structures: neurons and increased
quantity of astroglial tissue
Border tissue of Jacoby (a cuff of astrocytes)
separates the nerve from the choroid
The loose glial tissue does not bind the axon
bundles together as do the Muller cells of the
retina
the disc swells so easily in papilloedema
while the adjacent retina does not
SO
18. Lamina Cribrosa
Fibrillar sieve-like structure
Composed of fenestrated sheets of scleral
connective tissue lined by glial tissue
Bundles of ON fibers leave the eye through LC
Border tissue of Elsching:
- rim of collagenous tissue with few glial cells
- intervenes b/w the choroid and sclera & ON
fibers
19. Retrolaminar Region
Characterized by decrease in astrocytes &
acquisition of myelin supplied by
oligodendrocytes
Addition of myelin sheath doubles the diameter
of ON (from 1.5 to 3.0 mm) as it passes through
the sclera
Axonal bundles are surrounded by connective
tissue septa
The posterior extent of the retrolaminar region
is not clearly defined
20.
21. Ophthalmoscopic Features of
Optic Nerve Head
Optic Disc: part of nerve head visible with
ophthalmoscope
Intra papillary parts:
-optic cup & neuroretinal rim
-separated by scleral ring of Elsching
22. Why the normal disc is Pink
Light entering the disc diffuses
among adjacent columns of
glial cells and capillaries
Acquires the pink color of the
capillaries
Light rays that exit through
the tissue via the nerve fiber
bundles are pink
give the disc its characteristic color
&
23. NERVE FIBER LOSS IN CHRONIC
GLAUCOMA LEADS TO INCREASED
EXPOSURE OF THE LAMINA AS AXONS
ARE LOST SO THAT ITS PORES BECOME
MORE VISIBLE AS THE CUP ENLARGES, SO
THERE IS INCREASED WHITE REFLEX AT
DISC
Nerve fiber loss in chronic glaucoma:
- leads to increased exposure of the lamina as
axons are lost
- its pores become more visible as the cup
enlarges,
- there is increased white reflex at disc
24. Disc size
Disc shape
Usually oval
Vertical diameter being on average 9% longer
than horizontal diameter
The cup is 8% wider in the horizontal
Normal disc area ranges widely from 0.86 mm2
to 5.54 mm2
Macrodiscs: area > 4.09 mm2
Microdiscs: area < 1.29 mm2
25. Applied
Primary macrodiscs : associated with condition
such as pits of the optic nerve ‘Morning glory
syndrome’
Secondary macrodisc : associated with high
myopia and buphthalmos
NAION is common in smaller ON heads
due to problems of vascular perfusion and of
limited space
Same is true for optic nerve head drusen
due to blockage of orthograde axoplasmic flow
26. Pseudo papilloedema is encountered with smaller
optic nerve head
-particularly in highly hypermetropic eye
Susceptibility of the superior & inferior disc
regions to damage: due to higher pore-to-disc
area
27. Optic Cup
Funnel shaped depression
- varies in form & size
- usually off-centre towards
the temporal side
Cup correlates with disc:
-large in large discs
-small in small discs (may be absent)
3D measurement of cup shap: using confocal
miscroscopy or stereoscopic techniques
28. Neuroretinal Rim
Tissue outside the cup
Contains the retinal nerve axons as they enter
the nerve head
ISNT rule (inferior- thickest)
Greater axonal mass and vascularity in the
inferotemporal region
29. Applied
In primary open angle glaucoma:
- progressive loss of retinal ganglion cells
- leading to enlargement of cup, particularly at
upper & lower poles of disc
- leading to vertically oval cup
But: Horizontally oval cup-normal
Occurrence of flame shaped haemorrhages on
rim, usually at inferior or superior temporal
margin: early sign of glaucoma
30. Applied
Cup/Disc Ratio
Ratio of cup & disc width
Measured in same meridian, usually vertical or
horizontal
Doesn’t differ by more than 0.2 in 99% subjects
Asymmetry of greater than 0.2 is of diagnostic
importance in glaucoma
31. Parapapillary Chorioretinal Atrophy
Crescentric region of chorioretinal atrophy, found
temporally in normal disc
May be exaggerated in chronic glaucoma or high
myopia
Two zones of PPCRA:
more peripheral zone & is an irregular hypo- or hyper
pigmented region
Corresponds to RPE that failed to extend to the disc
margin
Zone alpha/choroidal crescent
32. Zone beta or Scleral Crescent
Related to disc centrally or zone alpha peripherally
Consists of marked atrophy of pigment epithelium
& choriocapillaries, with good visibility of larger
choroidal vessels
Applied
The zones are larger in total area & individually in
the presence of chronic glaucoma
33.
34. Retinal Vessels
Emerge on medial side of cup, slightly
decentered superonasally
Temporal arteries take an arcuate course as
they leave the disc
Nasal arteries take more direct, though curved
course
Course of arteries and veins is similar but not
identical
this avoids excessive shadowing of rods &
cones
35. Venous pulsation:
Arterial pulsation:
- observed at disc in 15-90% of normal subjects
- due to pulsatile collapse of the veins as ocular
pressure rises with arterial inflow into uvea
- rare, usually pathological
Eg. High ocular pressure or aortic incompetence
36. Intraorbital Part
Extends from back of the eyeball to the optic
foramina
Sinuous course to give play for the eye movements
Covered by dura, arachnoid and pia
The pial sheath contains capillaries and sends septa
to divide nerve into fasciculi
The SAS containing CSF ends blindly at the sclera but
continues intracranially
Central retinal artery, accompaning vein enter SAS
inferomedially about 10 mm from the eyeball
37. Applied
Posteriorly, near optic foramina, the ON is closely
surrounded by annulus of Zinn & origin of four
rectus muscles
Some fibers of SR & MR are adherent to its sheath
Account for the painful ocular movements seen in
retrobulbar neuritis
38. Relations of intraorbital part of ON
The long & short ciliary nerves & arteries
surround the ON before these enter the eyeball
B/w ON & LR muscle are situated the ciliary
ganglion, divisions of the oculomotor nerve, the
nasociliary nerve, the sympathetic & the
abducent nerve
The ophthalmic artery, superior ophthalmic vein
& the nasociliary nerve cross the ON superiorly
from the lateral to medial side
39.
40. Intracanalicular Part
Applied
Closely related to ophthalmic artery
OA crosses the nerve inferiorly from medial to
lateral side in the dural sheath
Leaves the sheath at the orbital end of the canal
Sphenoid and post ethmoidal sinuses lie medial
to it and are separated by a thin bony lamina
This relation accounts for retrobulbar neuritis
following infection of the sinuses
41. IntracranialPart
Lies above the cavernous sinus & converges with its
fellow to form the chiasm
Ensheaths in pia mater
Receives arachnoid & dural sheaths at the point of its
entry into the optic canal
Internal carotid artery runs, at first below & then
lateral to it
Medial root of the olfactory tract & the anterior
cerebral artery lie above it
Lies above the cavernous sinus & converges with
its fellow to form the chiasm
Ensheaths in pia mater
Receives arachnoid & dural sheaths at the point of
its entry into the optic canal
Internal carotid artery runs, at first below & then
lateral to it
Medial root of the olfactory tract & the anterior
cerebral artery lie above it
42. In the optic nerve head
Arrangements of nerve fibers in
optic nerve
Exactly same as in retina
Fibers from the peripheral part of the retina:
- lie deep in the retina
- occupy the most peripheral part of the optic disc
Fibers originating closer to the optic nerve head:
- lie superficially in the retina
- occupy a more central portion of the disc
43.
44. In the proximal region
In the distal region
Exactly as in retina
- i.e. upper temporal & lower temporal fibers are
situated on the temporal half of the optic nerve
- separated from each other by a wedge shaped
area occupied by the Pmb
The upper nasal and lower nasal fibers are situated
on the nasal side
The macular fibers are centrally placed
45.
46. 1.Surface nerve fiber layer
Intraocular part
Blood supply of optic nerve
Supplied by :
i. Peripapillary arterioles of CRA origin
ii. Epipapillary arterioles of CRA origin
iii. Rich anastomoses with prelaminar region
iv. Occasional anastomoses with choriocapillaries
v. Precapillary branches from cilioretinal arteries
when present
47. Retrolaminar region
Prelaminar and laminar region
Derive from short posterior ciliary arteries
Arterial circle of Zinn-Haller
Receives its supply mainly from arteries &
arterioles of pial sheath of neighbouring
leptomeninges
48. Applied
Optic disc edema occurs as prelaminar axons
swell from orthogonal axoplasmic flow at level
of lamina cribrosa
Insufficient blood flow through posterior ciliary
arteries due to thrombosis, hypotension,
vascular occlusion cause ON head infarction
49. Venous drainage of optic nerve head
In each zone:
- venules drain into central retinal vein
- or when present into a duplicated vein (an
embryonic persistence of hyaloid veins)
Occasionally septal veins in retrolaminar region
drain into pial veins
Some small venules from prelaminar region or
from SNFL (optiociliary veins) drain into choroid
51. Intraorbital Part
Supplied by 2 systems of vessels:- a periaxial
and an axial
Periaxial consists of 6 branches of internal
carotid artery:
- Ophthalmic artery
- Long posterior ciliary arteries
- Short posterior ciliary arteries
- Lacrimal artery
- Central artery of retina before it enters ON
- Circle of Zinn
52. The axial system consists of:
- Intraneural branches of central retinal artery
- Central collateral arteries which come off from
CRA before it pierces the nerve
- Central artery of ON
53.
54.
55. Intracanalicular Part
Ophthalmic artery is sole supply to this portion,
except occasional branch from CRA on its inf.
aspect
Branches from ophthalmic artery arises within
the canal or in the orbit
Pial network is poor in this region, because
arteries reach pia along connective tissue bands
binding the nerve to surrounding dural sheath
57. Intracranial part
Perichiasmal artery : branch of superior hypophyseal
branch of ICA
Runs back along the medial side of the ON, joins its
fellow of the opposite side along the anterior border
of the chiasm & supplies both
It is probably the largest supply to intracranial part
Ophthalmic artery gives number of small collateral
arteries running backwards along inferior surface of
nerve, winding round its margin in superior aspect
Additional branches from anterior cerebral artery and
anterior communicating artery also supply the same
60. Venous Drainage
Chiefly by central retinal vein
& to lesser extent via pial venous system
Both system drain into the ophthalmic venous
system in the orbit
& less commonly directly into cavernous sinus
61. Blood brain barrier at the optic nerve
The capillaries of ON head, the retina and the CNS,
have non- fenestrated endothelial linings with tight
junctions b/w adjacent endothelial cells
These are responsible for blood tissue barrier to the
diffusion of small molecules across capillaries
However it is incomplete as a result of continuity
b/w the extracellular spaces of choroid and ON head
at level of choroid (in prelaminar region)
There is no barrier to diffusion across the highly
fenestrated capillaries of the choroid
62. Signs of Optic Nerve Dysfunction
Reduced VA
Afferent pupillary defects
Dischromatopsia
Visual field defects
64. Lesions of the optic nerve
Lesions of the visual pathway
Complete blindness on the affected side
Abolition of direct light reflex on ipsilateral side
& consensual on contralateral side
Near (accommodation) reflex is present
Causes- optic atrophy
-Traumatic avulsion of optic nerve
-Indirect optic neuropathy
-Acute optic neuritis
65. Lesion through proximal part of optic nerve
Ipsilateral blindness
Contralateral hemianopia
Abolition of direct light reflex on affected side &
consensual on contralateral side
Near reflex is intact
66.
67. Disc usually lacking physiological cup
Have crowded appearance mimicking
papilledema
Hyperopic Optic Disc
Myopic Optic Disc
Disc is larger
Surrounded by white crescent of bare sclera, on
the temporal side
CDR is bigger mimicking glaucomatous cupping
70. Optic Disc Coloboma
Results from an incomplete closure of the embryonic
fissure
Defect of the inferior aspect of ON
White mass: glial tissue fills the defect
Inferior NRR: thin or absent, superior NRR: relatively
normal
72. Optic disc pit
Round or oval, gray or white depression in the optic
disc
Commonly found temporally
73. Tilted optic disc
Occurs when nerve exits the eye at an oblique angle
Superotemporal disc: raised, simulating disc swelling
Inferotemporal disc: flat or depressed
Resulting in an oval-shaped disc with long axis at an
oblique angle
74. Optic disc drusen
Globules of mucoproteins & mucopolysaccharides that
progressively calsify in the optic disc
Thought to be the remnants of the axonal transport
system of degenerated retinal ganglion cells
75. Morning Glory Disc
Congenital funnel shaped excavation of the posterior
pole
White tuff of glial tissue covers central portion of cup
Blood vessels appear to be increased in no. & emanate
from the edge of disc
76. Optic nerve hypoplasia
Optic nerve head appears abnormally small due to a
low no. of axons
Gray or pale disc surrounded by light- colored
peripapillary halo
Double ring sign
77. Aicardi syndrome
Rare genetic disorder in which corpus callosum is partly
or completely missing
83. References
Wolff’s Anatomy of the eye and orbit by Bron,
Tripathi and Tripathi
Anatomy and Physiology of eye by A.K. Khurana
2nd edition
Comprehensive Ophthalmology by A.K. Khurana
5th edition
AAO- Fundamentals & Principles of
Ophthalmology : sec 2
Walsh and Hoyt’s Clinical Ophthalmology
Internet
Non:occlusion of spcr..resulting complete or partial infarction of optic disc
Hyperaemic disc swelling and splinter haemorrhage
Arteritic: giant cell arteritis
Is a granulomatous necrotizing arteritis of large and medium sized arteries partc.ophthalmic posterior ciliary artery
Pale chalky white edematous disc