This content outlines a systematic five-rule approach ("5 Rs") for interpreting visual field test results, crucial for diagnosing and monitoring conditions like glaucoma. It emphasizes verifying the test's validity, analyzing reliability indices, probability plots, nerve fiber layer patterns, and reaffirming the diagnosis through clinical correlation and potential retesting.
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Coming now to presenting the five Rs,
the five rules in the visual field interpretation
interpretation
and I would like thank the popular
lecture on this topic the forge lecture
focusing theology and reframing locom evaluation
evaluation
which has been done uh and sponsored by
allergen in 2013.
So starting with these five rules, five
Rs, the first R is the right test,
then reliability,
then the review of probability plots,
then the arena of layer patterns of
loss, and then reaffirming the diagnosis.
And we'll explain each rule in details
in the following slides. First rule
be sure that the rightest was used.
So the right test we should coming we
should came across all these points.
Check the strategy. Check the similar
size the field size the eye the age the
by confirming the date of birth the
pupil size and the refractive error.
We'll see here the OD which means the
right eye. We'll see here
the stimulus size. says three and wide
packaging 31.5 a post strategy saf
diameter here it's missing should be
mentioned should be more than 3 mm mm
and visual accurities also should be
mentioned and here the refractive error
plus two and here's the date of the test
the time of the test and the age of the
patient all these should be confirmed
before starting ing reading the visual
field print out. Okay.
So we'll confirm the right strategy by
confirming the SA standard as we say SA
first. It's not recommended for
patients with the gluccom because
because it can underestimate
the scotoomas. So ideally should be SA
standard the Swedish interactive fish algorithm
algorithm
here you will find it's the strategy SA
standard then you will check the right
stimulus size was used and we said that
the HR visual field analyzer use the
goldman size three
as a standard. Sometimes you can use the
size five as we said for advanced visual
field loss or decreased visual acuity.
This is the five wide stimulus in these
cases in the advanced gluccom.
Then you should
check the the right field size as we
said the 24-2 is the standard size
central 24-2 threshold test. However, 10-2
10-2
it's very important in advanced gluccom
to check the progression and it's very
important for visual field loss within
the central 10 degree of fixation as we
said like gluccom or gluccom suspect 10%
of them will be having uh defects and on
then you will check that the right age
the date of birth of patient
has been reported. Why? Why this is
important? Because there is correction
to the normative database. There's a
Goldman table that adapted from the
Humphrey field analyzer instruction
booklet. Depending on the age, they will
correct for the refractive error. For
example, if the patient is between 45 49
years, they will add plus two their
sphere. And that's why they correct
normative database. So very important
please check the age check the date of
birth for the patient and also you will
check the refractive error you will see
the refractive error for example for
this patient having minus 1.25 to five
diotric sphere and also the correct
pupil size more than 3 mm because small
pupils meio pupils or people taking
pyocarbon drops or any myotics agent
will have small pupils so they can block
the peripheral stimulus sometimes
causing uh force peripheral decreased
uh retinal sensitivity and therefore
force peripheral field effects. So it's
very important to check the correct
pupil size. Here it's mentioned 3 mm.
The second rule coming to the second
rule we should check the real
reliability of the field. Is is this
print out reliable or no? By
main three indices.
These indices are the false positives
and false negatives and the fixation
losses. I will explain these three in
details in the following sides and you
will see them in the print out
in the upside in the up left side
corner. Here you will see the details
related to the
rightness and here here you will see the
data related to the reliability indices.
The first indices is the force positive
rate which is very important indices to
check that this visual field print out reliable
reliable
and it's the percentage of the time that
patient respondent in the absence of
stimulus and the id rate is should be
should be less than 10%.
If you see false positive rate more than
3 33% this is unreliable test and you
should be cautious when you see that the
false positive rate more than 25%. Why?
Because elevated false positives
can artifactually improve the appearance
of the field. And there's some patients
they just click
keep clicking they calling calling them
trigger happy because they keep
responding in the absence of any
stimulus. So this is very important
reliability indices you should always
check it before reading the print out
and you here you see false positive
errors 2%. Ideally should be less than 10%.
10%.
Coming to the second one which is the
false negative rate. the secondary
reliability indices
uh which is the percentage of time that
patient failed to respond to a stimulus
that should have been seen based on past
responses. So it's the force negative
basically is a negative response with
brighter than the threshold stimulus in
previous tested point. So the patient
will see a point then the test
testing machine will show at the same
same location higher pressure simulas.
The patient should see it. However, the
patient will not click,
will not respond. And this seen
especially in patient falling asleep can
reflect fatigue.
And if you see it more than 33%, it's
unreliable and you should use it with
caution in more than 25% false negative
rate. However, however, some
testing algorithms
have no longer using the force negative
rate uh index. Why? Because in advanced
visual field damage, when you have
visual field damage, the false negative
rate will be higher will be high because
of the variability
in receiving the stimulus in these
advanced visual field damage location.
So they said that force negative rate
sometimes can be not related to fatigue
or falling asleep but related to
advanced visual field. So some tests
some doctors they don't depend depend on
it fully but they depend mainly on the
force positive index and the uh fixation
loss that we will say uh that we will
discuss in the following slide.
Coming to the fixation losses
reliability index. This is the
percentage of the times that the patient
responded to a stimulus that presented
as the plotted plank blind spot and this
is we call it uh
hail carac method where they present a
point to the blind spot. Okay. And the
patient will respond. So there's no way
how will he respond to a stimulus
presented at the blind spot. However,
so consider as fixation loss.
However, it has main drawback. We'll
talk about it in the following slide. So
fixation loss is usually increase if the
patient doesn't maintain fixation, keep
moving his eye,
the patient head moves or the blind spot
was incorrectly located at the beginning
of the test.
And this is the main drawback of the uh
hail kaku method where they present a
similar to the uh uh plotted blind spot
because if you locate the blind spot
incorrectly in the beginning of the test
this uh fixation loss measurements will
be unreliable and you should use with
caution when you see the rate more than
20% fixation loss and if you see that
the fixation loss rate more than 33% %
this is unreliable test. Okay.
Okay.
And here you see the fixation losses is
four out of 15.
So as we said the original method was
hail KCO method where they presented
they present similars at the plotted
blind spot mapped in the beginning of
the test. However, the main drawback
that if you incorrectly locate the blind
spot at the beginning of the test, this
will increase the fixation losses
uh flessly
and it will appear that the test is
unreliable. So what Humphrey visual
field did they
use what we call it gaze tracker where
they use infrared in order uh uh
infrared light in order to check the
gauge stability
uh during throughout the test and you
will see at the bottom of the print out
gaze stability line. You will see it
like a line like that here in these
points. it means that the gaze was was
stable. However, when you see it up, it
means that the eye move. So, upstrokes
means that there was increased eye
movement and if you see downstrokes, it
means that there was uh lead uh
movement. So, this new uh a new uh
technique by Hford visual field
analyzer, it's much better than the
original method ho method which depend
on the blind spot. However, the gaze
tracker depend on infrared light that
follow and uh control the gaze during
throughout all the test.
We have other indices
just other clues that this test is not
uh reliable is unreliable.
But this test these uh uh points are
just clues that help you to understand
the full print out. So shortterm fluctuation
fluctuation
short-term fluctuation means that they
retest 10 pre-selected points and then
they calculate the difference between
the original test and the retest
threshold. So first we they will select
10 points that the patient answered uh
to them. Then they will retest these 10
uh pre-selected points and then they
will calculate the difference between
the original test and the retest
threshold and if they uh see that the
difference more than four decibel so
this mean that the short-term
fluctuation increase and this measure
the consistency an indicator of
reliability and also can be one of the
early signs of gluccom. Sometimes the
patients see see it and some sometime
doesn't doesn't uh see it. So
uh as we said this short-term
fluctuation one of the indicator of
consistency and reliability if it's
increased there is suspicious. However
the uh SA algorithm doesn't calculate
we have what we call corrected pattern
standard deviation to the short-term uh fluctuation.
fluctuation.
Uh and this corrected uh pattern
standard deviation. We'll talk about the
pattern stand deviation the following
side the pattern send deviation will be
corrected to the short short-term fluctuation
fluctuation
and it measures the localized
variability the localized irregular
irregulatory. So if you see high
corrected but standard deviation means
high uh uh localizer regulatory and
highly suspicious for gluccomatus damage
and in octopus not in hump visual field
care always must be taken when you see
the reliability factor values more than
10%. Which is mainly depending on the
this shortterm fluctuation during the
test. So it's like intrais variability.
Not only that we have another uh or
others uh reliability indices. The
reliability is low when there is more
than 5
50 550 simulas are projected or when the
test takes more than 8 18 minutes.
Usually to to determine the threshold
point dislocation uh five stimulas are
needed. In patients with field defects
more stimulus is needed. So if you if
you see that the stimulus more than uh
550 are projected or the test takes more
than eight 18 minutes
it means that the reliability of the
test is low. Always we have very popular
uh field effect uh on the a grayscale
map individual field print out representing
representing
uh reliability index the clever leaf
pattern. If you see this clever leaf
pattern it mean that the patient
becoming fatiguable in in attentiveness
with time
and I will talk about it just in the
following slide. And also if you see
increased I upstrokes or lead
downstrokes movement on I track a line
or the gear tracker line it means that
there is some unreliability because of
the fixation. So this is the unre
unreliable field because of the clever
leaf appearance which means that the
patient becoming fatiguable becoming
inattentive becoming doesn't concentrate
losing concentration.
So they will test
in the beginning of the test very well.
However, when they coming with time they
will lose concentration, lose energy and
motivation to respond well. So this
appearance of the field like clever leaf
uh uh it will show. So uh the four
primary points around the fixation are
checked and confirmed. If you see then
here you will see this is uh all field
doses. This clever leaf patterns means
So rule number three review the
probability plots.
Coming now to the global indices the
most important one and we'll talk about
the most two important global indices.
The first one is the mean deviation the MD
MD
which is from the just the name you
understand that it's talking about the
mean average and deviation so it's the
average loss of the entire field in decibels
decibels
or in other ways the depression
the loss from compared to the age normal
hill vision as we said previously the
hill vision is like conceptual model to
understand the visual field normal and
abnormal pyramid representing the hill.
This the maximum point in the hill is
the phobia where there is the maximal
visual threshold uh sensitivity and when
you go to the periphery there is
reduction in this retinal sensitivity to
the threshold to visual threshold and if
you see in a gluccom patient they will
start losing in periphery. However
patient for example with uh ordic
nuritis will start loss of the central
uh uh hill of the pigeon. So if you see
this average loss of the entire field
decibels compared to the age normal
corrected data give you the mean deviation.
deviation.
And for example, if you have a patient
with minus4 decibel, it means that it has
has
on average four decel loss less than the
normal age adjusted population.
It means that he has four disable four
decibels depression at all points in the
field or depression of eight decibels
over half of the field. Both of them
would give uh MD or mean deviation 47.
The most important point this one the
more negative MD the more worse feel. So
if you see here minus 10 it's not like
minus one
and this probability the p values the
probabilities given for that MD would
occur normal individual. So this MD for
example it can happen in less than 5% of
normal individuals and if you say it 1%
it means that this MD mean deviation can
happen in less than 1% of normal
population. So 99% of this MD uh having
abnormal result you understand what is
the meaning of p value it's like p value
Coming now to the second most important
uh global index which is the pattern
standard deviation
which is a measurement of focal visual
loss. So it's a measurements not of a
global or focal field loss
which means that it's the standard
deviation of each point from the age
corrected normal and it measures the
variability or local irreg
irregularities of the field. The more
positive the more bad not like the MD
the more negative the more bad here the
more positive higher pattern standard
deviation means higher variability
higher irregularity in the fields which
means there is localized field field
damage and in the ocular hypertension
treatment study the PSD the pattern
standard deviation identified as one of
the out of five important contributions
contributors to the risk of developing
gluccom. coma.
However, this pattern standard deviation
in normal patients or severely affected
visual field, they will have low pattern
standard deviation because in advanced gluccom
as we say that this PSD the pattern
standard deviation can decrease because
the damage is no longer focal. It will
be all the field reduction.
there is like a generalized reduction in
the uh visual visual field uh like
tunnel vision. So because there is no
localized irregularities because of the
advanced loss the patent cell deviation
will be low. However, in general the
higher pattern cell deviations means the
As we said coming to the numeric results
and grayscales these are the numeric
results and corresponding with a map
grayscale map we have threshold
sensitivity map. This sensitivity map uh
it has numerical facial sensitivity of
each location by decibels. And this one
the this map you should depend on. And
this corresponding grayscale map should
be used for education for patients
and the higher the threshold value or
the brighter the gray scale means the
higher sensitivity. So if you see blackish
blackish
uh the gray scale means that the patient
has low sensitivity. Okay. The higher
the threshold value it means the
brighter the gray scale and the higher sensitivity.
These uh probability plots divide into
the total deviation and into the pattern
deviation. And we say that you should
depend on the numeric uh plot not on the
gray scale. Gray scale should only be
used for patient education.
So these are the total deviation and the
pattern deviation. And the total
deviation like representing like the
mean deviation the MD point uh the
threshold at each point corresponding to
the age matched data and the pattern
deviation presenting the localized
regulatories like the PSD the pattern
standard deviation. So here the uh total
deviation probability map or numeric
numerical probability map and here is
the pattern deviation uh probability map
and you will see along with the
grayscale map in the bottom of the print out
out
uh sometimes the grayscale and
probability plots may not agree that's
why we I told you you should depend on
the numerical probability plot because
this is the more accurate than
a grayscale map.
So this grayscale map it can give you
impression that this field is normal.
However, when you see to the numerical
probability plot, you will discover that
this patient has a scotoism field effect
and it's abnormal field comparing to
just looking to the gray scale map. So
please look at the numerical probability plot.
plot.
These total and pattern deviation are
one of the most useful as aspects of the
automated pyramid.
We said that they compare the field data
of the patient respond to the normative
age match database.
They examine the depress points. You
should examine the depress points. Not
only that the number of contagious
depressed points, the location of these
depressed points and the severity of
these depressed points. So always please
these three points you should take in uh
consideration when you see uh the total
and deviation map. So you will see the
first the number of contagious depressed
points, the location of the depressed
points and the severity of these uh
And as we said then you will look at the
uh global indices will they will be on
the right lower corner to the uh mean
deviation to the pattern standard
deviation and you to the gluccom
hemophil test and we will say what is
the meaning of gluccom field test in the
following slide we'll see here the mean
mean deviation the MD you will see here
the patent standard deviation the mean
deviation the more negative the more bad
The pattern show the deviation the more
positive the more bad and this is the
probability that this deviation is found
in normal population.
The gluccom hemfield test which is the
third marker which is very important in
the global indices evaluate the
asymmetry between the superior and
inferior fields.
They choose clusters to mitate the
anatomy of the written and ner fiber layer.
layer.
Use these uh
clusters, compare them between the
patient hemisphere, between the superior
hemisphere and the lower hemisphere and
to normative age uh corrected uh
database and they will say three uh
responses. We will talk about them
outside the normal limits borderline and
normal. You see for example here the
superior field compared to the inferior
field there is a symmetry difference
between the superior field minus 2020
this a bit compared to minus 3 and the
fear field. Uh so in the print out you
will see that the gluccom heield test
outside the normal
or borderline
or within the normal. They mean that the
glaucoma hemophil test or GHT outside
the normal limits that the difference
between the upper and lower defects not
found 99% with the gluccom
that this difference is found in less
than 1% of normal patients and this
gluccom hemophilus in this patient is 99%
99% abnormal.
abnormal.
Okay. And if you see that the glaucoma
hemophilus is borderline this means that
the difference is not found in 90% of
patient without gluccom that this difference
difference
could be present in less than 3% of normal.
normal.
Okay. However the third result is the
glaucoma hemophilus within normal
limits. So combining the MD the PSD and
the gluccom hemophil testus along with
the maps you will discover that this
patient have gluccom or
we have last index is the visual field
index. Okay this uh visual field index
is like a global index expressing the
visual field as a percentage of the
normal age adjusted visual field. give
greater weight to the points close to
the fixation and less sensitive to the
catac. These are the main benefits that
less sensitive to the cataract and media
changes compared to the MD and PSD.
However, it requires a minimum five
tests over the 3 years
and despite that it is less sensitive to
cimedia changes not to immune to
artifact. There's some artifacts can
happen like fatigue of the patient and
other causes of uh uh artifacts in
visual field and also the rates of
progression as we know decreases as
gluccom severity increases because it
looks like it reached the maximum uh
reduction. So uh it will not appear on
the visual field index as a rate
progression. So it's very very useful
marker to follow the progression of
gluccom patients in uh uh every serial
gluccom. However, in the severe advanced
cases you cannot depend on you know the
visual field index as a marker of
progression but in general it's very
Number four
as we said we say three rules. Now
coming to the rule number four the RNF
layer pattern of field loss.
So please always look at the pattern
deviation blood and this pattern
deviation blood should be consistent
with the gluccomatus damage of nerve
fiber layer bonding. So if you see here
the pattern deviation of the written ner
fiber layer
the uh
parententral defect with nasal sting
with gluccomic field outside the normal and
and
minus 3.6 Six dibels mean deviation and
7 dibels pattern uh standard deviation
this representing gluccom
all also as we said that sometimes the
paracententral ar defect may be very
small to be seen in 24-2 here the same
patient if you see here there's one uh
uh scotoma one field lost minus 27
discipline. This is in grayscale map.
But however you when you do 10-2, you
will see that the paracententral arc are
enough layer defects much higher. Not
only that
it's much higher. So sometimes these
paracententral arf layer defect as we
said previously
you can take them using the 10-2. I'm
stressing more in this point just to
keep them uh uh memorized by heart. So
sometimes also as we said the benefit of
the total deviation compared to pattern
deviation of the C reduction in the
total deviation uh uh probability map
and you see normal pattern deviation.
This mean that the media is he has could
be due to cataract could be due to
coral his or conal edma. However,
sometimes this cataract with generalized
field loss can obscure localized
effects. For example, here in this
example the total deviation map is
showing uh total uh reduction
generalized field loss. So if you depend
only in this map total deviation map
you'll see okay this is due to cataract.
However when you look to the pattern
deviation you will see severe field
loss. So sometimes catact with
generalized field loss can obscure the
localized effect. So you need in order
to interpret it interret the visual
field print out correctly to always read
the total and the pattern deviation
maps. Here
uh the RNF layer pattern is the nasal
loss as you see nasal stabbing with
borderline gluccom hemophil test
representing a early or moderate
gluccom. Here you see that there is
arute loss.
Okay. Of the written near fiber layer
with gluccom hemophil testing outside
Here you see that there is hemi field
loss and this is common in advanced
glaucoma. This is the total deviation
map as we said sometimes can generalize
field loss can be happen due to cataract
or media his media his media. However,
the pattern deviation showing uh severe
hemophil loss which is common in albang
gluccom with outside normal limits
gluccom in field test and minus 14 14.3
decibel mean deviation with very high 1313
1313
decibel pattern standard deviation.
So please look at all these parameters
in order to interpret the print out very
carefully. Now coming to the rule number five,
five,
reaffirm the diagnosis. Please always
reassess the retina and the optic nerve
seeking the consistency with visual
field. You're not you are not
visual field interpreter. You are not AI
model. You are clinician, physician,
read the visual field in the context of
the patient examination
and please repeat the test if needed and
we will say why just in few seconds. You
know that 85% of patient with abnormal
fields in ocular hypertension study they
turned out normal after retesting them.
So please repeat the test if needed and
reframe the disease severity if
appropriate. Okay. So
always reaffirm the diagnosis confirm
abnormal field even in experienced field takers.
takers.
As we say that 85%.9
of abnormal fields reverted to a normal
on subsequent testing in ocular
hypertension study
and this is one example on 2nd April
1997 one of the patient showing inferior
field effect
and when they tested after one week it
reverted to normal.
And why we should reaffirm the diagnosis
of each patient because we have factors
that affect the final result of visual
field. We have factors related to the
patient. Some patients they have
variable adaptiveness. Some patients
will fatigue will be fatiguably during
the test. Some patients will fall
asleep. Some patient are inexperienced
with visual field testing. some factors
related to the parimetric and the role
was uh or the role of parimetric was
more important in the manual uh uh
visual field. However, on the uh uh in
the automated visual field the role
becoming less. However, they have very
important role in counseling the patient
explaining the patient to the p
explaining to the patient the test
explain where they expect the uh to see
the uh stimulus how they will see it. uh
teach them when to stop and how to stop
the test. These are very important
factors during uh uh the test for the
perimetress also the refraction. Please
always correct the refractive error. If
the patient has refractive error and you
they didn't correct it, the patient
surely will have reduced visual field
will have visual field uh uh loss. So
please correct the refractive error also
consider press prospia
and sometimes there's lens frame
artifact when you uh if they are too far
from the lens okay uh they they they
will not see the triggers that are
touching the periphery so it will show
the lens peripheral field uh loss
because of the lens rim artifact. So
please consider all these points uh
before getting final results from this
print out. Also the pupil size because
if you have small pupil the light that
entering the eye will be much less.
Uh so the uh sensitivity to the uh
simulance will be much less. Okay. And
this is especially when the pupil size
less than
2.5 mm or less than 3 mm. And we said in
the previous rule that you should
correct you should that uh you should
check that the correctness has been done
during the pub size should be always
more than 3 mm. Okay.
Okay.
Now we have just a summary of how how
interpret the visual field. If you see
that the nor the MD mean deviation is
normal and the corrected
and the uh corrected uh
pattern standard deviation which is as
we said the short-term fluctuation
corrected to the pattern standard
deviation normal and the total deviation
plot clean the pattern deviation plot is
clean so this is normal diagnosis and if
you see that the MD is abnormal and the
corrected And the B deviation is normal
with many abnormal points in the total
deviation plot with a clean B deviation
blood. This mean that there is
generalized loss of sensitivity like for
example cataract or hazy media.
But if you see that there is normal MD
with abnormal corrected PSD and abnormal
total deviation blood with abnormal
patent deviation blood this most
probably gluccom due to localized
effects. Okay. Or localized effect due
to glaucom or other causes. And if you
see that there is abnormal MD with
abnormal corrected BSD with abnormal
total deviation blood with abnormal
pattern deviation blood this mean that
you have both generalized and localized
effects. Okay. For example, this can be
happen in advanced gluccom.
We have just final touch to conclude the
uh the reading the interpretation of
visual field. The addition criteria this
is very important criteria parametric
criteria for the diagnosis of gluccom.
So this criteria has three points in
order to say that this patient has a
glaucoma depending on the pyramid. Okay,
only the first point that pattern
deviation probability plot has a cluster
of more than three non-edge points with
probability less than 5% at least one of
them one point with probability less
than 1%. Which mean that one of them one point
it has 99% that this point is abnormal.
Okay. with pattern standard deviation
probability less than 5% with a gluccom
hemophilus outside of normal limits. So
if you see these three points together
this is confirming parametric diagnosis
of a glucona. Okay, depending on this
some authors, clever authors generate a
web application for automatic
classification of the gluccomatus visual
field using a criteria and they uh name
it as gluccom field defect classifier.
You have the website and this their
paper was published in nature digital
medicine journal
and you will see here like the uh
website you will uh upload the patent
deviation plot. This is the link of the
website. Okay. And then you will uh
write the mean deviation the global plot
central disable values and the visual
accuracy option and run analysis and
they will say you most probably this
patient have a glome. Okay.
Now coming to the case studies, we'll
explain some case studies in order for
you to memorize by heart how to
interpret the visual field uh collecting
all the data that we said in the
previous uh slides. The first case you
have 57 year old man with no complaint
within 66 both eyes with IUB 22 mm
mercury in both eyes and small disc size
with no cup. you will follow the five
rules that we introduce and uh have to
how to how to interpret the visual field
print out correctly. Okay, first rule is
this the right test. Okay.
So you will check here the uh field size
central 25 uh 24-2. We will check the uh
stimulus size 3 wide the background 3
31.5 step the strategy set a strand
standard the be diameter for mm there is
refractive error and the left eye the
the edge of the patient and the date of
the birth or check please the is this is
the right was used. Second rule, the
reiability. You look for the reiability
indices on the up left corner of the
print out. You will see the fixation
loss. He has almost uh no fixation
losses, the false positive uh rate and
the false negative uh error rate. Okay.
Then so in the this list the reliability
in this is uh telling that this visual
field is reliable. Then you will review
the probability plots the total
deviation the pattern deviation. You
will see here that you have uh uh field
loss nasally okay nasal step on the
total deviation and the pattern
deviation map okay
with many of them less than 1%
probability and this patterns of the
retin fiber layers nasal stabbing we
call it and the five will reaffirm the
diagnosis this is mod gluccom okay and
you can look for the other parameters we
said hey the gluccom He field test
outside the normal the mean deviation
and the pattern standard deviation.
Please if you uh watch this YouTube
lecture you will explain every point in
this print out. Okay please
be focused. The second case is a 40 year
old man vision 66 IB 25 mm American both
eyes with average of the disc and
superior fear uh rim thinning. The first
rule is this a right test okay this is
24-2 threshold test what are the
other parameters the similar size the
background the strategy the size you
will follow you will check all these
points before reading the print out then
you will go to the reliability indices
the fixation losses the false positive
false negative rates you will see them
that this is this is reliable we say the
fixation uh ideally should be less than
10% false positive false negative uh
should be uh less than uh 33%
ideally should be less than 25%.
Okay. Then you will go to review the
probability plots. You will see that
there's some unspecific changes in the
total deviation plot. However, the
pattern deviation plot is clear. You
will check the written n fiber pattern
written n fiber layer pattern. You will
see that the gluccom he filters this
with a normal
and you reaffirm diagnosis. This is
normal standard automated pyramid. Okay.
So you now understand every point in the
print out the case three.
This is 58-year-old man seen 9 years ago
with a UB between 24 28 average disc
visual field normal and present for
followup with a UB 22 mm mercury both
eyes. Now we'll uh combine between the
two lectures I presented between the two
five rules for assessment of the optic
discing gluccom and five rules of
interpretation of visual field uh print
out. The first rule you will observe
this clear ring in order to identify the
size of the optic disc. Then you will identify
identify
the size of the rim the is not rule.
Then you will examine the retinal ner
fiber layer. Then you will examine the
region of parapilar of beta zone and
alpha zone. Then you will look for any
retinal or optic disc. Okay. So the
first rule see the scular ring rim. This
is average disc size. Then you will see
that there is inferior written and nerve
fiber layer filling inferior notch. So
there is no uh violated. Then you will
see there is diffuse retinal nerve fiber
loss. There is no written loss at all in
this image.
Then you will see that we have betazone
parapiliatrophy. This is the betazone
parapillary atrophy and there is no dis
hemorrhage or even retinal hemorrhages.
Okay. Now this is clinically a gluccom.
However, combining these five hours of
the optic nerve examination visual field
interpretation, you will check you did
visual field for this patient. You check
this is the right test. Okay. 24-2. You
will go through all these parameters to
check that this this was the right one
to use. Then you will go to the
reliability and this is fixation losses
first positive false negative. You will
see that this disc is reliable. Then you
will review the probability plus both
the total deviation but in deviation you
will you will see nasal sib you will
review the written ner fiber layer and
see sing along with glaucoma hemophil.
So this is moderate gluccom
combining both the optic nerve
So this is the final print out as we
said here the reliability indices data
relative fixation loss force positive
force negative. This is the related to
the right test the test duration the
test strategy the stimulus size packing
ground the pub dam the visual acuity the
date of the test the time of the test
the age of the patient and then you will
see the threshold numerical probability
map and the grayscale map. Here you will
find the uh total deviation map uh along
with the patent deviation map and the
grayscale maps. Here you will see the
glaucoma hemop field test along with the
visual field index as we said the mean
deviation with the pattern standard
deviation and here at the bottom the
print out you will see the gaze tracker.
And now by ending this lecture you will
able to understand every point in this
print out. So please read it and
memorize it by heart and you need
sometimes to repeat it and thank all
what I give in this lecture is only the
tip of the iceber and there's too much
data about pyramid the other types of pyramid
pyramid
and the diagnosis of gluccom. Thank you
all for listening for this uh uh
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