This document provides an overview of fundamental laser ophthalmology. It begins with laser physics, describing the principles of stimulated emission and population inversion required for laser action. It then discusses the properties of laser light including monochromaticity, directionality, coherence, polarization and intensity. The document outlines different laser systems used in ophthalmology and laser-tissue interactions, focusing on photocoagulation. It explains the basic mechanism of photocoagulation, factors in choosing the appropriate wavelength, and discusses photocoagulation in the clinical context of conditions like diabetic macular edema and retinal neovascularization.
Laser science is principally concerned with quantum electronics, laser construction, optical cavity design, the physics of producing a population inversion in laser media, and the temporal evolution of the light field in the laser. It is also concerned with the physics of laser beam propagation, particularly the physics of Gaussian beams, with laser applications, and with associated fields such as non-linear optics and quantum optics.
Laser science is principally concerned with quantum electronics, laser construction, optical cavity design, the physics of producing a population inversion in laser media, and the temporal evolution of the light field in the laser. It is also concerned with the physics of laser beam propagation, particularly the physics of Gaussian beams, with laser applications, and with associated fields such as non-linear optics and quantum optics.
Lasers in ophthalmology - Dr. Parag Apteparag apte
A full presentation of one hour of all types of lasers in ophthalmology for under graduates and post graduates after going through all the uploaded slides till today. This includes laser photocoagulation, laser iridotomy, and laser capsulotomy in detail
What is laser; Its uses in dermatology; Types of lasers; Treatment options for acne scars, melasma; hyper pigmentation; wrinkles; warts; Dark skin, facial rejuvenation; stains; rosacea; hair removal options;
Basics refresher on Laser Technology and it's applications. Presentation prepared by (and for) student(s). Level- Karnataka State Pre-university PUC1(India)
Principles and uses of lasers in omfs /certified fixed orthodontic courses by...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
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Lasers in ophthalmology - Dr. Parag Apteparag apte
A full presentation of one hour of all types of lasers in ophthalmology for under graduates and post graduates after going through all the uploaded slides till today. This includes laser photocoagulation, laser iridotomy, and laser capsulotomy in detail
What is laser; Its uses in dermatology; Types of lasers; Treatment options for acne scars, melasma; hyper pigmentation; wrinkles; warts; Dark skin, facial rejuvenation; stains; rosacea; hair removal options;
Basics refresher on Laser Technology and it's applications. Presentation prepared by (and for) student(s). Level- Karnataka State Pre-university PUC1(India)
Principles and uses of lasers in omfs /certified fixed orthodontic courses by...Indian dental academy
The Indian Dental Academy is the Leader in continuing dental education , training dentists in all aspects of dentistry and offering a wide range of dental certified courses in different formats.
Indian dental academy provides dental crown & Bridge,rotary endodontics,fixed orthodontics,
Dental implants courses.for details pls visit www.indiandentalacademy.com ,or call
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Various laser lenses have been introduced following Goldmann 3- mirror and Goldmann fundus contact lens for retinal photocoagulation.
Below described some of the time-tested lenses in widespread use. Precise knowledge of these lenses is necessary for safe retinal photocoagulation.
Recent advances in ophthalmology - Dr. Parag Apteparag apte
A full presentation on recent advances in ophthalmology till today. There is not a single presentation on recent advances in ophthalmology in slide share till September 2017. I have tried my best to cover most of the topics so that the lecture gets over in one hour
Light is an integral part of our life. Advances in technology are increasing and changing the ways that the patient experience dental treatment. One of the milestones in technological advancements in dentistry is the use of lasers The early 20th century saw one of the greatest inventions in science & technology, in that LASERS which later went on to became a gift to health sciences. Albert Einstein is usually credited for the development of the laser theory. He was the first one to coin the term “Stimulated Emission” in his publication “Zur Quantentheorie der Strahlung”, published in 1917 in the “Physikalische Zeitschrift”
Lasers are devices that produce beams of coherent and very high intensity light. The word LASER is an acronym for “Light Amplification by Stimulated\Emission of Radiation”. A crystal or gas is excited to emit light photons of a characteristic wavelength that are amplified and filtered to make a coherent light beam. The effect of the laser depends upon the power of the beam and the extent to which the beam absorbed. Several types of lasers are available based on the wavelengths. These range from long wavelengths (infrared), to visible wavelengths, to short wavelengths (ultraviolet), to special ultraviolet lasers called excimers. Lasers are used nowadays in many areas in the field of dentistry It is of the most captivating technologies in dental practice. Even though, introduced as an alternative to the traditional halogen curing light, laser now has become the instrument of choice, in many dental applications. Its advancements in the field of dentistry are playing a major role in patient care and well being.
ANALYSIs TECHNIQUES : Spectroscopies - SHREYA NAIR
INTRODUCTION - Spectroscopies are useful for chemical state analysis (bonding or charge transfer amongst the atoms), electronic structure (energy gaps, impurity levels, band formation and transition probabilities) and other properties of materials.
RAMAN SPECTROSCOPY
PHOTOLUMINESENCE SPECTROMETER
AUGER ELECTRON SPECTROSCOPY
X-Ray and Ultra Violet Photoelectron Spectroscopies (XPS or ESCA and UPS)
REFERENCE
THANK YOU
NW2012 Intraocular Lens Design and Effects on VisionNawat Watanachai
some information about intraocular lens materials, designs; and their effect on surgery and visual function.
I'm sorry that i one i previously uploaded was the wrong file.
The Gram stain is a fundamental technique in microbiology used to classify bacteria based on their cell wall structure. It provides a quick and simple method to distinguish between Gram-positive and Gram-negative bacteria, which have different susceptibilities to antibiotics
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
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
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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
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
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.
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.
New Drug Discovery and Development .....NEHA GUPTA
The "New Drug Discovery and Development" process involves the identification, design, testing, and manufacturing of novel pharmaceutical compounds with the aim of introducing new and improved treatments for various medical conditions. This comprehensive endeavor encompasses various stages, including target identification, preclinical studies, clinical trials, regulatory approval, and post-market surveillance. It involves multidisciplinary collaboration among scientists, researchers, clinicians, regulatory experts, and pharmaceutical companies to bring innovative therapies to market and address unmet medical needs.
12. Laser Physics
• Element of laser
1. Active medium
• Allowed stimulated emission
• Particular atomic energy transition
Wavelength of the emission
E = hv = hc /λ
13. Laser Physics
• Element of laser
1. Active medium
• Gas : Argon, Krypton, Carbon dioxide,
Argon-fluoride excimer, Helium with neon
• Liquid : Dye
• Solid : Supported by crystal
Nd:YAG, Er-YLF, Ruby
Infrared holmium-YLF (IntraLase)
holmium-YAG(Laser thermal
keratoplasty)
Semiconductor (diode)
14. Laser Physics
• Element of laser
2. Energy input
• Make majority of atom are in higher energy state than
ground state
• “Population inversion”
• “Pumping”
• “Light amplification”
15. Laser Physics
• Element of laser
2. Energy input
• “Pumping”
– Gas laser : Electrical discharge between
electrode in gas
– Dye laser : Other laser
– Solid crystal : Incoherent light
(Xenon arc flash light)
16. Laser Physics
• Element of laser
3. Optical feedback
• Promote stimulated emission, suppress spontaneous
emission
• Spontaneous emission not amplify
• Stimulated emission Coherent laser
18. Properties of laser
1. Monochromaticity
– Laser emit light only 1 wavelength /
combination several wavelength
– Gas laser 0.01 nm
– Color of light enhance target tissue absorption
or transmission
– Not effected by chromatic aberration
in lens system
– Focus in smaller spot > white light
19. Properties of laser
Chromatic aberration
– Distortion, a failure of lens to focus all colors to the
same convergence point
– Lens have different refractive index for different
wavelength (↓ refractive index - ↑ wavelength)
20. Properties of laser
1. Monochromaticity
– Laser emit light only 1 wavelength /
combination several wavelength
– Gas laser 0.01 nm
– Color of light enhance target tissue absorption
or transmission
– Not effected by chromatic aberration
in lens system
– Focus in smaller spot > white light
21. Properties of laser
2. Directionality
– Laser emit a narrow beam
– Laser amplify only photon that travel along
narrow path between 2 mirrors
– Cause collimating light
– ↑ 1 mm in diameter of beam for every meter
travel
– Focus light to small spot
22. Properties of laser
3. Coherence
– Ability of 2 light beams, or different parts of the
same beam, to produce interference
– Interference
23. Properties of laser
3. Coherence
– “Laser speckle” -- rough surface
– Laser interferometer
Laser beam split to 2 beams
Diffuse by cataract
Overlap in retina
“Interference fringes”
• Non contact biometry (IOL master)
– Partial coherence interferometry
27. Properties of laser
4. Polarization
– Certain direction of light wave
– Linearly polarized
• Electric fields of light wave in the same plane
• Allow maximum transmission through laser medium
without loss caused by reflection
28. Properties of laser
5. Intensity
– Power in a beam of given angular size
– Most important property
– “Brightness”
• Intensity / unit area
29. Properties of laser
5. Intensity
– Radiometric terminology
Term Unit
Energy joule
(1 J = 1 watt x 1 sec.)
Power watt
Energy density J/cm²
Irradiance watt / cm²
Intensity watt / sr
(sr = Steradian, unit of solid
angle)
brightness Watt / sr cm²
30. Properties of laser
5. Intensity
– Radiometric terminology
Term Unit
Energy joule
(1 J = 1 watt x 1 sec.)
Power watt
Energy density J/cm²
Irradiance watt / cm²
Intensity watt / sr
(sr = Steradian, unit of solid
angle)
brightness Watt / sr cm²
Laser output
31. Properties of laser
5. Intensity
– Tissue effect
• Determined by focal point spot size
• Energy density , irradiance
– Spot size
• 50 µm spot size = ¶ (25 x 10 -4) ² cm²
= 2 x 10 -5 cm²
36. Laser system
• Types of medical laser
– CO2 (λ = 9.2-10.8 µm)
• Gas laser
• Nonophthalmic surgery : Gynecology, ENT
• Absorbed by water
– Er:YAG (λ = 2.94 µm)
• Solid laser
• Strongest absorption by water shallow penetration
depth low vaporization, small collateral damage
37. Laser system
• Types of medical laser
– Nd:YAG (λ = 1064 µm)
• Important ophthalmic laser
• Low absorption and scatting deep penetration
– Argon/Krypton (λ = 488,515,568,647 nm)
• Gas laser
• Retinal photocoagulation in the past
– Excimer laser (λ = 157,193,248,308,351 nm)
• ArF (193 nm) Strong absorption in protein
submicrometer penetration in tissue
• Refractive surgery (Corneal ablation)
38. Laser system
• Contact lens
– Aberration
• Focal spot size of laser beam is limited by diffraction
and aberration
• ↑ central aberration ↑ focal spot size
• Photocoagulation Flat contact lens to control
aberration
– Magnify spot size on retina
– Increase view of field
46. Laser-tissue interaction
1. Photocoagulation
– Choice of laser wavelength
• Green laser
– Well absorb by melanin, hemoglobin, less absorb by
xanthophyll
– Retinal vascular abnormality, CNV
– Argon green laser (514 nm)
» Popular wavelength for retina photocoagulation
– Frequency-doubled Nd:YAG laser (532 nm)
» Continuous , pulsed output
» Its absorption and clinical use similar to Dye yellow but
more reliable due to solid medium
47. Laser-tissue interaction
1. Photocoagulation
– Choice of laser wavelength
• Red laser
– Good penetrate through cataract, VH than other laser
– Less absorb by xanthophyll
– CNV near fovea
– Deep burn discomfort
– Krypton red laser (647 nm)
» Well absorb only melanin
deeper outer retinal and choroidal
burn
» Less absorb by hemoglobin
good for VH, CNV
overlying thin subretinal Hge
bad for retinal vascular abnormality
48. Laser-tissue interaction
1. Photocoagulation
– Choice of laser wavelength
• Infrared laser
– Similar to red laser
– Deeper penetrate through tissue
– Semiconductor diode laser (805-810 nm)
» Near infrared spectrum
» Well absorb by melanin only
deeper outer retinal and choroidal burn
» Similar property to krypton red laser but less discomfort
due to near invisible laser (no sensation of flashing)
» Treatment of choice for ROP
» Transscleral contact retinal photocoagulation
Penetrate sclera and silicone scleral exoplant
49. Laser-tissue interaction
1. Photocoagulation
– Choice of laser wavelength
• Yellow laser
– Penetrate through cataract
– Less absorb by xanthophyll
– Destroy vascular structure with little damage to adjacent
tissue
– Dye yellow laser (560-580 nm)
» Well absorb by Hemoglobin, melanin
» Safe for macular photocoagulation
» Less useful in VH, preretinal hemorrhage, CNV overlying
with subretinal hemorrhage
56. Laser-tissue interaction
1. Photocoagulation
– Photocoagulation mechanism
• Retinal break
– Laser and cryotherapy adhesion and scar
– Adhesive force generate within 24 hours several weeks
to its maximum strength
– Laser > Cryotherapy
» Less breakdown of blood retinal barrier
» ↓Risk proliferative vitreoretinopathy
64. Background
• Traditionally laser burns have been placed one by
one in a grid pattern
100-500 µm
100-200 ms
Total spots ≥ 1500 spots
Several sessions
65. Background
Blumenkranz MS
PASCAL (PAttern SCAn Laser)
• A new frequency doubled 532 nm
Nd:YAG laser
• Delivering arrays up to 56 spots
over less than 0.6 sec following a
single foot step
• Less painful and safer alternative to
argon laser for both PRP and
macular photocoagulation
66. Background
Pattern scan laser
• Short pulse duration result in a quicker PRP procedure
• As pulse durations < 50 ms
X Thermal energy
Mechanical rupture
• because of transient vapor formed adjacent to
melanosomes
• Without thermal energy
– laser-induced damage is limited to RPE and
photoreceptors, sparing choroid and inner retina
67. Background
Pattern scan laser
• Decrease perception of pain
– Mechanical rupture effect do not diffuse to sensory neuro
rich choroid as seen in Argon laser
• Safe
– Inner retina and choroid are spared
– However, as pulse duration < 50 ms
– Smaller safety margin when titrating power of the PASCA
68. Background
• However, they are not aware of any study that has
compared clinical outcomes for the 2 lasers when treating
high-risk PDR
• This retrospective comparative study evaluates efficacy
between PASCAL and traditional argon laser in treating
newly diagnosed high-risk PDR
69. Methods : Procedure
Argon laser
• 514-nm (green) pulses
• 1 burn width apart
• Indirect headset
• Slit-lamp microscope with contact
lens
• spot-size magnification factor
of 2x
• Pulse duration 200 ms
• Spot size 200-300 µm
• Power 200 mW increased by
10-20 mW until a gray/white
lesion
• 2 or 3 sessions
(37% completed PRP in 1 session)
PASCAL
• 1 burn width apart
• Small or larger array was
determined by operator
• Slit-lamp microscope with contact
lens
• spot-size magnification 2x
• Pulse duration 20 ms
• Spot size 200 µm
• Power 200 mW increased
until gray/white lesion
• 2 or 3 sessions
(44% completed PRP in 1 session)
70. Discussion
• PASCAL has greater speed and comfort
• When both lasers were applied with similar number and
size of laser spots in similar patients
– PASCAL treatment was less effective in inducing regression
and preventing recurrence of NV in high-risk PDR
• Inherent difference in properties of PASCAL and argon
lasers
– Limits efficacy of PASCAL when used in context of traditional
argon laser treatment parameters
71. Discussion
-PRP scars following treatment with argon laser are larger size than with
PASCAL
-Total area of PRP scars in the argon-treated patient exceeds that of the
PASCAL-treated patient by an order of magnitude
72. Discussion
• Increasing rate of recurrence NV experienced in the
PASCAL-treated patients
– Given equivalent number of treatment spots, PASCAL created smaller
total burn area results in a significant decrease in efficacy compared to
Argon laser
– Either additional lesions or larger spot sizes may be required to
achieve comparable efficacy with PASCAL
73. Conclusion
• PRP with PASCAL less effective than traditional
argon green laser in high-risk PDR to achieving
treatment goals when using traditional argon
green laser parameters
• Increasing number, spot size, or duration of laser
burns may improve efficacy of PASCAL as
measured by rates of regression and recurrence
NV
81. Laser-tissue interaction
2. Photodisruption
High peak power pulsed laser
(Nd:YAG, Er:YAG)
Ionize target tissue and increase tissue temperature
to exceed vaporization threshold
Vapor bubbles
Rupture tissue within zone of bubbles
91. Reference
• Daniel Palanker, Mark S. Blumenkranz, John J. Weiter. Chapter 21 Retinal
laser therapy : Biophysical basis and application. Retina. Forth edition.
Elsevier Mosby
• Steven M. Bloom, MD, Alexander J. Brucker, MD. Laser surgery of the
posterior segment. Second edition. Philadelphia: Lippincott-Raven; 1997.
• American academy of ophthalmology : section 12 Retina and vitreous,
Basic and clinical science course, 2010-2011
• American academy of ophthalmology : section 10 Glaucoma, Basic and
clinical science course, 2010-2011
• Antonia M. Joussen, Thomas W. Gardner, Bernd Kirchhof, Stephen J.
Ryan. Retinal vascular disease. New York: Springer
• Aimee V. Chappelow, Kevin Tan, Nadia K. Waheed, Peter K. Kaiser.
Panretinal photocoagulation for proliferative diabetic retinopathy : Pattern
scan laser versus Argon laser. Am J Ophthalmol 2012;153:137-142
92. "The important thing is not to stop
questioning.
Curiosity has its own reason for
existing."
Albert Einstein