Light and laser sources can cause retinal injury through photochemical and thermal mechanisms. The retina is susceptible to damage from sunlight, welding arcs, medical instruments like operating microscopes, and lasers. Protective mechanisms like the cornea, lens, and retinal pigment help absorb harmful wavelengths. Retinal injuries present as yellow lesions and can cause vision loss, though recovery is possible. Precautions like filters, goggles, and minimizing exposure times are important to prevent light and laser injuries.
Vitreous hemorrhage is the extravasation, or leakage, of blood into the areas in and around the vitreous humor of the eye.[1] The vitreous humor is the clear gel that fills the space between the lens and the retina of the eye. A variety of conditions can result in blood leaking into the vitreous humor, which can cause impaired vision, floaters, and photopsia.
It's an indepth presentation by Dr. Shah-Noor Hassan.
Vitreous hemorrhage is the extravasation, or leakage, of blood into the areas in and around the vitreous humor of the eye.[1] The vitreous humor is the clear gel that fills the space between the lens and the retina of the eye. A variety of conditions can result in blood leaking into the vitreous humor, which can cause impaired vision, floaters, and photopsia.
It's an indepth presentation by Dr. Shah-Noor Hassan.
MACULAR FUNCTION TEST PRESENTATION VERY IMPVidhiMadrecha
The macular function test is very important test... To understand the maula dis function and amount of disfunction. It is very useful for Central and colour vision.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
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.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
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.
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
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
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.
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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
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Anti ulcer drugs and their Advance pharmacology ||
Anti-ulcer drugs are medications used to prevent and treat ulcers in the stomach and upper part of the small intestine (duodenal ulcers). These ulcers are often caused by an imbalance between stomach acid and the mucosal lining, which protects the stomach lining.
||Scope: Overview of various classes of anti-ulcer drugs, their mechanisms of action, indications, side effects, and clinical considerations.
2. Light and Laser Injury
Structural damage to the retina
produced by any type of light source.
3. Mechanism of damage
Photochemical &Thermal retinal damage possible
Potential causes
1 solar eclipse
2 welding arc
3 lightning,
4 ophthalmic
instruments,
5 Laser
4. LIGHT INTERACTION WITH
THE RETINA
The eye primarily perceives radiation in
the optical spectrum, comprised of
the visible (400–760 nm)
Ultraviolet (UV; 200–400 nm), and
Infrared (IR; > 760 nm).
Radiation in this region can be
produced by the sun, ophthalmic
instruments, and lasers
5. Associated features
■ Delayed appearance of the lesion after
the injury by hours to days
■ Variable recovery of vision
■ Severity of damage proportional to
increased duration and intensity of
exposure
6. Mechanisms to reduce retinal light
exposure.
The cornea absorbs most UV-B (280–315 nm) and
UV-C (< 280 nm), as well as some IR radiation, and
reflects up to 60%
of incident light that is not perpendicular to its surface.
The lens absorbs most UV-A (315–400 nm) and visible
blue wavelengths.
Retinal xanthophyl absorption of near-UV and blue light
to protect the photoreceptors,
Choroidal circulation control temperature
Intracellular moleculardetoxification of free radicals and
toxic molecules.
Physiologicalprotective mechanisms include the
eyebrow ridge, squint and blink reflexes, the aversion
response, and pupillary miosis.
7. Light damage to the retina
may occur when
Protective mechanisms are impaired
متعمدDeliberate gazing at a light source.
Young patients may be at increased risk due to
efficient light transmission through ocular
media.
8. PHOTIC RETINOPATHY
Damage disorder of RPE and photoreceptor
Temporally Permanent;
Recovery noted in solar retinopathy welding arc
maculopathy , and operating microscope
phototoxicity .
Mild sever
9. Retinal injury and the visual recovery
depend on multiple factors
The location and area exposded , the duration,
intensity, and spectrum of the light source, and host
susceptibility factors, such as age, nutritional status,
ocular pigmentation, core temperature, clarity of
ocular media, and pre-existing retinal disease.
Emmetropes and hyperopes may be at increased risk
caused by effective focusing of light on the retina.
Systemic photosensitizing agents, such as
tetracycline, hematoporphyrins, and psoralen, may
predispose to photochemical damage.
10. Solar (eclipse)Retinopathy
Religious sun gazing, solar eclipse,,sunbathing,
psychiatric disorders,
Solar radiation damages the retina through
photochemical effects,
Symptoms develop 1 to 4 hours by decreased
vision. usually improves within 6 months
A small yellow spot with a gray margin may be
noted in the foveolar or parafoveolar area
FA reveal transmission defects due to RPE
irregularity
OCT, demonstrates disrupted reflectivity in the
outer retina, or fragmentation of the highly
reflective layer corresponding to the junction
between the IS OS
Oral corticosteroids treat acute lesions,
11. Welding Arc Exposureاللحام
keratitis due to cornea UV absorption.
A yellow edematous lesion occurs
acutely in the fovea which is replaced
over time by an RPE irregularity or a
pseudomacular hole.
Vision usually improves with time
12. البرقLightning Retinopathy
Lesions described include macular edema,
macular hole, cyst, or a solar retinopathy-like
picture, cataract, retinal detachment, retinal
artery occlusions
Visual recovery often occurs over time, even
with severe maculopathy.
High-dose intravenous methylprednisolone
treatment may play a role in recovery of
vision
13. Retinal Phototoxicity from
Ophthalmic Instruments
Retinal injury has been described
following exposure to light produced
by the operating microscop
7% of patients having cataract
operations demonstrated
operating microscope phototoxicity
The mechanism of
intraoperative phototoxicity is
photochemical but may be thermally
after 60 minutes of
operating microscope light exposure,
despite the presence of UV and IR
filters,
14. The lesion is yellow round
FA of the acute lesion
reveals fluorescein
leakage at the level of
the RPE which may
simulate the
appearance of choroidal
neovascularization.
Subsequent weeks, the yellow
lesion fades and is replaced
by permanent areas of RPE
clumping and atrophy
FA blocking and transmission
defects, respectively
Long-term squeal
Retinal surface wrinkling. -
Choroidal neovascularization
15. Measures to avoid this complication
1-Minimizing length of surgery
2-Minimizing light output,
3-Using filters,
4-Rotation of the globe by a superior rectus suture,
5-Maximizing light pipe distance from the retina
6-using eccentric and variable endoillumination
techniques
7-Placement of an air bubble corneal cover
9-Retinal examinations be performed with
the minimal illumination required
16. LIGHT EXPOSURE AND AGE-
RELATED
MACULAR DEGENERATION
An association between long-term solar exposure and
AMD was considered
when AMD was found to be less common in patients
who have nuclear cataract
Solar observation acutely damages the RPE and
produces RPE pigmentary irregularities, which are
similar in appearance to those in AMD
The use of hats and sunglasses to filter UV was
inversely associated with the prevalence of soft,
indistinct drusen.
17. LASER INJURY
Laser applications in industrial, military,
and laboratory situations
account for accidental retinal injury.
-Subtle lesion -Macular hole
-Hemorrhage -Foveal cyst –
-Yellow RPE irregularities
-Epiretinal membrane
-Macular hole - Gliosis.
Recovery of vision is variable and is
related to the extent and location of
the initial injury.
Corticosteroids have been used to
treat laser-induced and laser pointer
retinal injuries.
Foveal cyst
18. In the ophthalmology setting
Lasers operators slit lamp or
operating microscope
contain filters to protect the
operator
Decreased color discriminatio
has been noted in
ophthalmologists who used
the argon blue-green.
Persons in the laser area
are at risk from laser light
scatteredfrom optical
interfaces such as
contact lenses and
mirrors
The risk is related to their
distance from the laser,
Protective goggles
should be worn.
19. LASER
POINTERS
Laser pointers are portable low energy devices that
emit a very narrow coherent low-powered laser
beam of visible light.
These devices are used to illuminate an item of interest
with a spot of brightly colored light
Laser used by ophthalmologists for retinal therapy
generate between 5 and 500mW
The FDA specifies that laser pointers between 1–5 mW
20. LASER POINTERSCont.
There is misuse of these handheld lasers.
.The mechanism of injury is thermal chorioretinal damage
There is visual abnormalities and scotom .
FA demonesterat perimacular hyperfluorescence correspond to RPE
window defect
Visual acuity improved to 20/20 and visual field returned to normal within8
weeks, but a subjective decrease in brightness and foveal RPE
These pointers that exceed recommended standards may produce
permanent retinal injury and visual impairment with resultant
photoreceptor damage
21. COMPLICATIONS OF
THERAPEUTIC RETINAL LASER
PHOTOCOGULATION
Inadvertent photocoagulation of the fovea,
cornea, iris, or lens can be minimized
with use of careful technique
and appropriate laser settings
22. Cont. COMPLICATIONS OF
THERAPEUTIC RETINAL LASER
PHOTOCOGULATIONpanretinal photocoagulation
spread over multiple sessions
Decreases in laser intensity and duration, avoid smaller spot sizes (50 μm),
with the use of the krypton red laser