Presented By our respected teacher
Mohammad Siddique (Optometrist)
Thank You sir
Final Year Student Of Optometry at ISRA School Of Optometry
All Rights Reserved
It describes about the procedure of Hess charting. it serves as a great tool to understand the concepts involved. Suitable for optometry course. This is not a routine procedure but an important procedure which is used in diagnosis.
Contrast sensitivity is defined as the Ability to perceive slight change in luminance between regions which are not separated by definite borders or Ability to perceive sharp outlines of relatively small objects or Ability to detect separation of the area of different contrast level
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
Image Quality, Artifacts and it's Remedies in CT-Avinesh ShresthaAvinesh Shrestha
CT is one of the frequently used diagnostic imaging modalities in Radiology. Knowledge about image quality and artifacts is essential when diagnosing a patient with the help of CT images. Moreover, Radiology Technologist's should be very well aware about the ways to identify and eliminate or minimize the artifacts in CT for better image quality.
It describes about the procedure of Hess charting. it serves as a great tool to understand the concepts involved. Suitable for optometry course. This is not a routine procedure but an important procedure which is used in diagnosis.
Contrast sensitivity is defined as the Ability to perceive slight change in luminance between regions which are not separated by definite borders or Ability to perceive sharp outlines of relatively small objects or Ability to detect separation of the area of different contrast level
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
Image Quality, Artifacts and it's Remedies in CT-Avinesh ShresthaAvinesh Shrestha
CT is one of the frequently used diagnostic imaging modalities in Radiology. Knowledge about image quality and artifacts is essential when diagnosing a patient with the help of CT images. Moreover, Radiology Technologist's should be very well aware about the ways to identify and eliminate or minimize the artifacts in CT for better image quality.
Low vision patient have serious visual problems that have caused serious visual loss.
1. Contrast sensitivity testing and visual field testing
2. subjective testing of patients with media loss
# potential acuity meter
# interferometry
# photostress recovery test
# glare test
# color vision test
# dark adaptometry
3. objective testing of retinal loss
# USG
ERG/EOG
VISUAL ACUITY , Basics of vision assessmentssuserde6356
Visual acuity (VA) is a measure of the ability of the eye to distinguish shapes and the details of objects at a given distance. It is important to assess VA in a consistent way in order to detect any changes in vision. One eye is tested at a time.
Go to:
Indications
To provide a baseline recording of VA
To aid examination and diagnosis of eye disease or refractive error
To assess any changes in vision
To measure the outcomes of cataract or other surgery.
Go to:
Equipment
Multi-letter Snellen or E chart
Plain occluder, card or tissue
Pinhole occluder
Torch or flashlight
Patient's documentation.
Go to:
Procedure
Ensure good natural light or illumination on the chart. It is important to ensure that the person has the best possible chance of seeing and reading the test chart as treatment decisions are made based on the results of VA testing.
If the test is done outdoors, the chart should be in bright light and the patient in the shade, with enough light to illuminate the patient's face during the test.
Explain the procedure to the patient. Tell patients that it is not a test that they have to pass, but a test to help us know how their eyes are working. Tell them not to guess if they cannot see.
Ensure that any equipment that the patient touches is clean and is cleaned between patients. Infections can be passed between patients if equipment – or the testers' hands – are not clean.
Position the patient, sitting or standing, at a distance of 6 metres from the chart. The patient can hold one end of a cord or rope of 6 metres long to ensure that the distance is maintained
Test the eyes one at a time, at first without any spectacles (if worn).
Note: Some people prefer to always test the right eye first. Others prefer to test the ‘worse’ eye first (ask the patient out of which eye they see best). This ensures that the minimum is read with the ‘worse’ eye, and more will be read with the ‘good’ eye. This means that no letters are remembered, which could make the second visual acuity appear better than it is.
An external file that holds a picture, illustration, etc.
Object name is jceh_27_85_016_f04.jpg
Visual acuity should be measured from a standard distance, using a standard chart with a white background
Ask the patient to cover one eye with a plain occluder, card or tissue. They should not press on the eye; this is not good for an eye that has undergone surgery. It can also make any subsequent intraocular pressure reading inaccurate and it will distort vision when the occluded eye is tested.
Ask the patient to read from the top of the chart and from left to right. If the patient cannot read the letters due to language difficulties, use an E chart. The patient is asked to point in the direction the ‘legs’ of the E are facing.
Note: there is a one in four chance that the patient can guess the direction; therefore it is recommended that the patient should correctly indicate the orientation of most letters of the same size, e.g. four out of five or five out
Presented by our respected teacher
Mohammad Siddique (Optometrist)
thank u sir
Final Year Student Of Optometry at ISRA School Of Optometry
All Rights Reserved
Explore natural remedies for syphilis treatment in Singapore. Discover alternative therapies, herbal remedies, and lifestyle changes that may complement conventional treatments. Learn about holistic approaches to managing syphilis symptoms and supporting overall health.
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.
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
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
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
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.
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stockrebeccabio
Factory Supply Best Quality Pmk Oil CAS 28578–16–7 PMK Powder in Stock
Telegram: bmksupplier
signal: +85264872720
threema: TUD4A6YC
You can contact me on Telegram or Threema
Communicate promptly and reply
Free of customs clearance, Double Clearance 100% pass delivery to USA, Canada, Spain, Germany, Netherland, Poland, Italy, Sweden, UK, Czech Republic, Australia, Mexico, Russia, Ukraine, Kazakhstan.Door to door service
Hot Selling Organic intermediates
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
2. Definition:
Contrast:- defined as the degree of blackness to
whiteness of target.
Contrast threshold:-is the smallest amount of contrast
required to be able to see the target.
Contrast sensitivity:- is the reciprocal of the contrast
threshold.
3. the ability to perceive slight changes in
luminance between regions which are not
separated by definite borders and is just as
important as the ability to perceive sharp
outlines of relatively small objects.
4. Snellen’s charts test VA at a very high contrast
thus many patients have a good snellens VA but
they may be visually handicapped in real life
situations.
The VA drops in the situations with low contrast
and the quality of vision is not good.
It provides the information that cannot be
obtained from visual acuity, and it is often a
better predictor of visual performance then VA.
5. C .S is presented as
curve which plots
the lowest contrast
level a patient can
detect for specific
size target.
The x-axis curve is
for spatial
frequency, y-axis is
for contrast
sensitivity.
6. The contrast sensitivity function proposed by
Manos and Sakrison.
A plot of CS over a range of spatial frequencies
gives the contrast sensitivity function(CSF).
Contrast sensitivity depends on spatial frequency.
Spatial frequency of visual stimuli is given in
cycles per degree.
7. Contrast sensitivity function (CSF) is a
subjective measurement of a person's ability
to detect a low contrast pattern stimuli,
usually vertical stripes of decreasing shades
of black to grey. The resulting measurement is
said to give a more accurate representation of
the eyes' visual performance.
8. CSF has a peak value
of approximately 1 to 8
cycles/ degree.
Distinction of high
frequencies not
possible because of
limited number of
photoreceptors.
9. Neural and optical
attenuation limits
the high spatial
frequency CS.
Point where the
CSF cuts the x axis
is called cut off
frequency.
10. MICHELSON FORMULA:
L max- Lmin/Lmax+Lmin
Lmax = Luminance on the lighter surface
Lmin = Luminance on the darker surface
WEBERS FORMULA:
Defined as ( Lb – Lt ) / Lb
Lb & Lt are the luminance of the background and
target respectively.
Weber contrast used in calculating the contrast of
letters.
12. • The modulation transfer function (MTF) indicates the ability of an optical
system to reproduce (transfer) various levels of detail (spatial
frequencies) from the object to the image.
• Its units are the ratio of image contrast over the object contrast as a
function of spatial frequency.
• It is the optical contribution to the contrast sensitivity function (CSF).
13. MTF: Cutoff FrequencyMTF: Cutoff Frequency
0
0.5
1
0 50 100 150 200 250 300
1 mm
2 mm
4 mm
6 mm
8 mm
modulationtransfer
spatial frequency (c/deg)
cut-off frequency
57.3
cutoff
a
f
λ
=
⋅
Rule of thumb: cutoff
frequency increases by
~30 c/d for each mm
increase in pupil size
14. One adjacent pair of light and dark bars
makes up one cycle.
The thickness of the grating is described by
their spatial frequency in cycles per degree of
the visual angle at the eye..
Large number of grating can fit with in a
degree of visual angle
15. Gratings are broader and are of low spatial
frequency.
Spatial phase defines its position.
Change in spatial phase by 180 degrees
indicates that the grating is displaced by half
a cycle.
16. These gratings are
lacking in sharp
borders.
Sinusoidal gratings are
used because they
are not subject to
defocus,
aberration,diffraction,
light scatter.
Only the contrast and
spatial position are
affected.
20. Detection of striped pattern at various levels of
contrast and spatial frequency.
Sine wave gratings of parallel light and dark
bands.
Measured with stationary gratings
width of the bar is defined as spatial frequency
High spatial frequency- narrow bars.
low spatial frequency- wide bars.
21. The spatial frequency
increases
exponentially from left
to right. The contrast
also varies
logarithmically from
100% at the bottom to
about 0.5% at the top
22. Temporal contrast sensitivity is measured with
gratings that reverse contrast at various rates over
time.
here contrast sensitivity function is generated
for the time related processing in the visual
system by presenting a uniform target field
modulated sinusoidal in time.
Both the system provides more complete and
systemic data on the status of visual
performance.
23. The shape of the contrast sensitivity function
varies with factors:
Luminance
Target size
Grating motion
Grating shape
24. Have problems with night
driving, including inability to
see traffic lights
May require extra light to read
Their eyes may become tired
when they read or watch
television
Not being able to see spots
on clothes, counters, or dishes
Missing facial gestures
25. There are three variables in measurement of
contrast sensitivity:
1. Average amount of light reflected depends on
illumination of paper and darkness of ink.
2.Degree of blackness in relation to white
background that is contrast.
3. The distance between the grating periods of
cycles per degree of visual angle.
26. The various methods available to measure CS
include
Pelli Robson test
Bailey Lovie chart
Vision contrast test system (VCTS) by Vistech
Cambridge low contrast grating
Regan charts
FACT charts
27. letters of the same
size but with
reducing contrast
two charts and two
scoring pads.
Each chart has 6
letters in each row
organized into two
triplets of varying
contrast.
illumination of the
chart is 85 cd/mm2
1 meter distance
28. The score of the test
is recorded by the
faintest triplet out of
which at least 2
letters are correctly
identified.
The log CS value for
this triplet is given
by the number on
the scoring pad.
29. It is a rapid and simple screening test for
contrast sensitivity.
Performed at a distance of 6m.
It comprises of 12 pair of plates consisting of
stripes of varying contrast.
First one is for demonstration and rest are for
the proper testing and are numbered from 1-10.
30. The plates are changed sequentially starting
from plate 1 till the patient fails to respond.
Then a new series is begun starting 4 plates
prior to where the patient failed to respond.
Four such series are completed and the score
of each series is noted (numbered as per the
number of plate read) and added.
The final total value is converted into contrast
sensitivity from the provided table.
31.
32. Low contrast acuity testing & acuity testing in
presence of glare.
Each row has same no. of symbols & constant
spacing is used between rows & letters.
Chart is logarithmic based & visual acuity is based on
log of minimum angle of resolution or logMAR.
Berkely Glare Test provides 10% of contrast & is
provided with glare source
33.
34. FACT charts were developed by Dr. Arthur Ginsburg.
FACT comprises of a chart with sine-wave gratings of
varying frequencies.
The chart tests five spatial frequencies (sizes) and
nine levels of contrast
The Contrast varies in a row, decrease from left to
right
35. And the spatial frequencies increase as one
move down the various columns from top to
bottom.
This test is performed at a distance of 10 feet.
The patient determines the last grating seen for
each row (A, B, C, D and E) and reports the
orientation of the grating: right, up or left.
The last correct grating seen for each spatial
frequency is plotted on a contrast sensitivity
curve.
36.
37. Introduced in 1978.
Consists of a booklet
containing several sine
wave gratings patterns
Each grating is oriented
vertically
The contrast varies from the
top to the bottom of the
grating, lowest at the top
and highest at the bottom.
38. These charts consist of sine wave gratings.
Each chart contains five rows and nine
columns of circular photographic plates (disc)
on gray background.
Each row has different spatial frequency (1.5 to
18 c.p.d. at three meters) and contrast within
the row reduces from left to right.
The gratings are presented in three
orientations: vertical 90 degrees, 15 degrees
clockwise or anticlockwise.
39.
40. Two separate Vistech charts are available: the
VCTS-6500 for distance testing and the VCTS-
6000 for near testing.
A projector slide the VCTS-500S is also
available.
A luminance of between 103 and 240cd/m2 is
recommended.
It can be used to document the performance of
low vision patients.
41. Consists of three letter charts, printed on white
cardboard having contrast of 97%, 7% and 4%
3 meter with eight letters in each line
Patients are instructed to start at the top and to
continue reading until they can correctly identify no
letters on a line.
For one chart letter size goes on reducing and
contrast remains constant
Regan in 1988 suggested there chief role in
detecting early visual loss in diabetes and
glaucoma.
44. Refractive errors:
Uncorrected refractive disorders manifest
themselves as a decline in contrast sensitivity
first at smaller grating sizes or higher spatial
frequencies for mild refractive disorders.
As the degree of refractive disorder increases,
contrast sensitivity declines at the middle and
then larger grating sizes (middle to lower
spatial frequencies).
45. Measurements were made at distance (with Vistech
charts), at near (with Arden gratings), and with a
pinhole to control pupil size.
Under all conditions, when visual acuity was
reduced by spherical lenses, there was a loss of
contrast sensitivity over a broad range of spatial
frequencies.
Ophthalmology 1988 Jan;95(1):139-43.
Eeffectof visual blur on contrast sensitivity. Clinical implication
Marmor MF, Gawande A
46. Age:
There occurs a definite decrease in contrast
sensitivity with increasing age.
The pathogenesis of this decline in vision is
likely involves changes in the spherical
aberration of the crystalline lens
47. As the aperture of lens increases the average
focal point move towards the lens so that a
larger pupil produces greater spherical
aberration
Spherical aberration of cornea changes little
with the age of the people.
48. Total wavefront aberration of the eye increases
more than threefold, between 20 to 70 years of
age.
the aging lens loses its balance with the
cornea, because both the magnitude and sign
of its spherical aberration change significantly.
A loss of balance between corneal and
lenticular spherical aberration causes the
degradation of optical quality in the aging eye.
49. Monocular and binocular contrast sensitivity function
for a range of spatial frequencies was measured in two
groups of subjects with normal vision.
In the age range 50-87 years there was a linear decline
in contrast sensitivity with age for medium and high
spatial frequencies, but sensitivity for low spatial
frequencies was independent of age.
Effect of age on contrast sensitivity function: uniocular and binocular findings
J E Ross D D Clarke and A J Bron.
50. Cataract:
Early cataracts generally cause contrast
sensitivity losses similar to refractive disorders
at higher spatial frequencies.
The addition of glare source will exacerbate the
results for patients with cataract, producing
lower contrast sensitivity at some or all grating
sizes
51. significant loss of contrast sensitivity at all spatial
frequencies with increasing cataract severity.
Contrast sensitivity was significantly reduced at
high spatial frequency (18 cpd) in cortical cataracts
in the presence of glare in day light and at low
spatial frequency (3 cpd) in night light.
Contrast sensitivity scores may offer additional
information over standard VA tests in patients with
early age-related cataracts.
Ophthalmic Vis Res. 2011 January; 6(1): 26–31.
Effect of Cataract Type and Severity on Visual Acuity and Contrast
Sensitivity
Javad Heravian Shandiz MSc, PhD,1
Akbar Derakhshan MD,2
52. Contact lenses:
to ensure proper contact lens fit as well as
determining when replacement is necessary.
Uncorrected residual astigmatism from soft
contact lens can result in decrease contrast
sensitivity at the middle and higher spatial
frequencies when compared to hard contact
lenses.
53. study concluded that those female professional
and collegiate tennis players wearing no
corrective lenses were significantly higher in
CS at intermittent and high spatial frequencies
than those who wore daily-wear soft contact
lenses in competition.
Kluka, D.A. and Love, P.A. “Effects of Daily – Wear Contact Lenses Upon Contrast
Sensitivity in Selected Professional and Collegiate Female Tennis Players,” UBA
at Birmingham
54. Glaucoma: Glaucoma can reduce contrast sensitivity for
all grating sizes, a number of studies shown reduce
contrast sensitivity mostly at the middle spatial
frequencies.
study was carried out to explore the effects of glaucoma
on low-spatial-frequency contrast sensitivity by using
tests designed to assess performance of either the
magnocellular (M) or parvocellular (P) visual pathways.
Sensitivity was reduced foveally and in the midperiphery
across the spatial frequency range. In the area of early
visual field loss, the glaucoma group demonstrated further
sensitivity reduction across the spatial frequency range.
55. The low-spatial-frequency-sensitive channels of
both pathways, which are presumably mediated
by cells with larger receptive fields, are
approximately equivalently impaired in
glaucoma.
Contrast sensitivity changes due to glaucoma and normal aging: low-spatial-
frequency losses in both magnocellular and parvocellular pathways.
McKendrick AM Sampson GP, Walland MJ, Badcock DR
Invest Ophthalmol Vis Sci.2007 May;48(5):2115-22
56. IOLs
A study was carried out to evaluate the contrast
sensitivity at near and distance after MFIOL
implantation in 21 patients. A control group with
monofocal iol was also studied. CS measured
after 1,3,6,12,and 18 months after IOL.
57. multifocal In patients with unilateral cataract,
monofocal, accommodating and partially diffractive
multifocal IOL provided higher CS scores when
compared with refractive IOL.
Clinical and experimental ophthalmology
Differences in contrast sensitivity between monofocal,
multifocal and
accommodatingintraocular lenses: long-term results
Cem Mesci MD, Hasan H Erbil MD, Ali Olgun MD, Nihat Aydin MD,
Article first published online: 3 NOV 2010 DOI: 10.1111/j.1442-
9071.2010.02357.
58. Diabetic retinopathy:
In diabetic retinopathy patients, contrast sensitivity
loss may occur for all grating sizes.
a study was carried out to evaluate contrast
sensitivity (CS) and visual acuity (VA) in detecting
functional losses in participants with type 2
diabetes.
LogMAR VA and letter CS were measured on 20 type
2 diabetic and 24 age-matched control participants.
The diabetic participants were sub-grouped
according to the level of retinopathy present.
59. RESULTS:
Letter CS was able to distinguish those participants
with and without macular oedema and those with no
or minimal diabetic retinopathy from the control
group, whereas VA was not.
Clinical optom 2003 May;86(3):152-6
Letter contrast sensitivity changes in early diabetic retinopathy
Stavrou EP, Wood JM
60. Optic neuropathies:
A variety of optic neuropathies including
afferent pupillary defect, optic neuritis, and
multiple sclerosis will affect contrast sensitivity
losses over some or all grating sizes.
Multiple sclerosis can sometimes affect only
middle sizes.
62. Cases report was made by
neuroophthalmological examination in two
patients with parasellar pituitary adenoma
before and after surgery.
The twelve months follow-up of visual
dysfunction includes standard Snellen visual
acuity and low contrast number visual acuity.
63. The presented cases indicate that the low contrast
acuity tests in patients with parasellar pituitary
adenoma are sensitive indicators.
The loss of low contrast visual acuity improved after
surgery as did other visual measures, except in
cases with significant low contrast deficit at 1.5%
contrast.
Kruzer, A.R. (1986) “ Contrast Sensitivity Signals Pitutary Adenoma,” Rev. Of.Opt. 123(4), 119
64. Toxic Chemicals:
Several occupational studies have indicated that
chronic, airborne exposure adversely affects
neurobehavioral functions in workers, particularly
visual color discrimination and tasks dependent on
rapid visual-information processing
Frenette, B.,Mergler, D. And Bowler, R.(1991) “Contrast Sensitivity Loss in Group of
Former
Microelectronics Workers with Normal Visual Acuity,” Opt. and Sci.,68(7),.
65. Why refractive surgery can affect the quality of
vision.
there are other factors in the eye, which affect
vision quality, that are unrelated to eye focus.
These factors can cause the quality of vision to
vary greatly, even when a patient has 20/20 or
better acuity. Contrast sensitivity is the best
method for quantifying the quality of vision