Perimetry is the technique of evaluating the Visual field .

Perimetry is the technique of evaluating the Visual field of patient to know about effect of ant optic nerve or retinal damage. It is the functional changes in the Visual field due to any structural changes in Ganglion cell complex and optic nerve due to Ischemic or non Ischemic or pressure induced damaged.

1. “The ideal glaucoma screening test is portable, easy to operate, highly
sensitive and specific, quick and patient friendly”
Johnson, et al, Glaucoma,2000

2. Octopus Perimetry Systems
OCTOPUSPerimetrycomprisesstandardwhite-on-
white(SAP),blue-on-yellow(SWAP),Flicker(CFF),
manualandautomatedGOLDMANN kinetic
perimetry.

4. SEVEN IN ONE GRAPH -OCTOPUS

7. Octopus Vs HFA

9. Octopus Global Indices

10. Octopus Visual Field Defect

11. HFA Criteria For Field Defect

13. Patient Data, Strategy and Test
Parameters

14. Grey Scale

15. Octopus: Comparision Table

16. HFA: Total And Pattern Deviation

17. Progression of a field
NEW DEFECT:
1.Anewclusterofatleast3nonedgeabnormalpoints
arisesinatypicallocation,eachwiththreshold
sensitivitiesoccurringinfewerthan5%ofthenormal
population(p<5%),andwithasensitivitythatoccursin
fewerthan1%ofthepopulation(p<1%)atoneofthe
points

18. Progression of a field
DEEPENING OF A PREEXISTING
DEFECT:adefecthasdeepenedorenlargedif2
ormorepointswithinoradjacenttoanexisting
scotomahaveworsenedbyatleast10dBor3times
theaverageofSF,whicheverislarger.
GENERALIZED DEPRESSION :
1.DeclineinMDthatissignificantatp<1%levelOR
2.CPSDshowinganobvioustrendbasedonlast5
consecutivefieldsOR
3.Declineof>3dBatallpointsontwoconsecutive
fields.

19. Procedures used for progression
Clinical judgment.
Defect classification systems.
Trend analyses
Event analyses

20. Trend analyses
Useoflinearregressionforpredictionforpredictionof
progress.
Adv:candeterminetemporalpatternsandhavethe
potentialtodetectsubtleprogressivelossfromtest
variability.
Disadv:
1)minimum7-8visualfieldsrequiredforadequate
sensitivity.
2)normalageingnotconsidered.

21. Event analyses
Useofpairedt-testtodeterminewhethersignificant
differencesarepresentbetweenonetestresultand
another.
Examplesare:
1)DELTAprogrammeonOCTOPUSperimeter.
2)GCPonSTATPAC2analysissoftwareofHFA.

22. How to follow up?
Establishabaselinefield/fields
Twoorthreesuccessivefields4weeksapartthatare
reproduciblearetakenasrepresentativebaseline
Incaseofseverelycontractedfieldsconcentrateonthe
central20or10degwiththe10-2orthemaculartests
Usageofalargerpatternofpoints.Eg.Ifthediagnosis
wasmadewitha24-2patternwithmostpoints
abnormal,convertingtoa30-2maybehelpful
UsageofalargersizeVstimulusincaseswithhigh
visualloss

23. Change analysis printout
Providesavisualdisplayofadditionaldescriptive
statisticswithlargenumberofexaminationsona
singlepage
Includesaboxplotpanelacrossthetopandseveral
graphsofglobalindicesofaseriesofexaminations
belowthepanel
Thevisualfieldsaredisplayedwitharegularinterval
betweenthemnotcommensuratewiththeactualtime
scale

24. The box plot
Themajorityofthresholdsensitivityestimationsare
closetothemidnormalvalueandthedeviationis
typicallynear0dB(the50
th
percentile)pointinthe
normalfield
Forthe30-2pattern70%ofthepointsliebetween3dB
and-3dBoftheaveragenormalvalues
Alltherestareexpectedtofallbetween4dBand-6dB

25. The box plot

26. Change analysis printout
Foreachexaminationthedeviationsaredeterminedat
eachpoint,thesearethetotaldeviationplotvalues
Averticalrectanglerepresentsrangeofdeviationfor
70%ofalllocations
Themeandeviationismarkedbyaflankedheavy
horizontalbar
Theendsoftheverticalbarsindicatethetotalrangeof
deviationsofallthepoints

27. Interpreting the box plot for progression
Ashortboxthatremainsofthesameheightbut
shiftsdownwardsindicatesprogressivegeneralised
depression.HereMDdecreasesbutPSDremains
unaffected
Lengtheningoftheboxespeciallyintheinferior
armindicatesdevelopmentanddeepeningof
localiseddefects.PSDbecomesincreasingly
abnormal
Alongboxatinitialexaminationthatstaysthe
samelengthandmovesdownwardindicates
progressivegeneralizeddepressionsuperimposed
onalocalizeddefect

28. The global indices on the C.A.P.

29. Mean deviation index
Observeitfirst
Ifalmostsameinmultipleexaminations,neithera
generaliseddepressionnoradeepfocaldefectis
occuring
HighlyvariableMDindexmeansexaminationisnot
reproducible
Steadyimprovementmeanslearningcurve
Steadydownwardtrendmeansprogressivelossof
fields

30. Other indices
ThePSDandCPSDincreaseasscotomasfirstdevelop
Theirprogressivedeteriorationishelpfulinearlyfield
losses
Aslossesbecomeadvancedtheymaystabilise(false
security)
HereSFtendstoincreaseasvariabilityatabnormal
pointsincreases

31. Glaucoma change probabilty
Itcameintovoguetodecidehowmuchof
variabilityfrombaselineisnormal.
Patientswererepeatedlytestedatvariousstagesof
glaucomaoveraperiodof<onemonth
Itwasobservedthatamountbywhichthe
thresholdfluctuatesintheabsenceofprogression
isaffectedbyhowabnormalthetestpointinitially
is
Onfollowupwedeterminehowunlikelyitisthat
theobtainedvalueatagivenlocationcouldhave
occurredasarandomfluctuation

32. Baseline field

33. Follow up fields

34. Follow up field

35. Follow up fields

36. Glaucoma progression analysis
Itisanadvancedsoftwaremodulethatupgrades
STATPACtoassistdetectionoffielddefectprogression
CanbeusedwithSITAstd,SITAfastandfullthreshold
algorithms
TheGPAhighlightsanychangefrombaselinethatare
largerthanexpectedclinicalvariability
DoesnotsupportFASTPACorcentral10-2

37. GPA print out components
LookssimilartotheroutineHVFprintout
Baselineisintheroutineoverviewformat
Followupprintoutsincludegraytone,pattern
deviationplots,deviationfrombaselineplotand
progressionanalysisprobabilityplot

38. Deviation from baseline plot
ThethirdcolomnintheGPAprintout
ComparesthePDofthefollowupfieldswiththatof
thebaseline
IndicateschangesateachtestedpointindBnotation

39. Progression analysis probability plot
FourthcolumnintheGPAprintout
Givesthestatisticalsignificanceofthedecibelchange
showninthedeviationfrombaselineplot
Compareschangesinthebaselineandfollowupfields
totheintertestvariabilitytypicalofstableglaucoma
andshowstheplotofpointsthathavechanged
significantly

44. A clinical example
77 yr old male diagnosed with POAG. The IOP in rt eye
was 28 mm and lt was 26 mm
CCT were 525 and 523 microns respectively
He was put on latanoprost both eyes with IOP
reducing to 16-18mm in both eyes

46. Rt eye field

47. Left eye field

48. He was lost to follow up for 2 yrs during which time he
defaulted on his therapy
Patient was folloed up on return with pressures of
18mm on latanoprost

51. Rt eye GPA single field analysis

52. Lt eye GPA single field analysis

53. J Glaucoma. 2006 Jun;15(3):206-12
Keratometry, optic disc dimensions, and
degree and progression of glaucomatous optic
nerve damage.
Jonas JB, Stroux A, Martus P, Budde W.
Large optic disc area is statistically significantly,
but clinically weakly, correlated with low
keratometric readings (diopters).

54. Invest Ophthalmol Vis Sci. 2005 Apr;46(4):1269-74
Central corneal thickness correlated with glaucoma
damage and rate of progression.
Jonas JB, Stroux A, Velten I, Juenemann A, Martus P,
Budde WM.
At the time of patient referral, the amount of
glaucomatous optic nerve damage correlated significantly
with a thin central cornea. Progression of glaucomatous
optic nerve neuropathy was independent of central corneal
thickness, suggesting that central corneal thickness may
not play a major role in the pathogenesis of progressive
glaucomatous optic nerve damage.

55. Graefes Arch Clin Exp Ophthalmol. 2005 Aug;243(8):741-7. Epub 2005
Feb 8
Progression of visual field defects and visual loss in
trabeculectomized eyes.
Ehrnrooth P, Puska P, Lehto I, Laatikainen L.
Progression of VF defects and development of visual impairment due
to glaucoma was fairly common despite trabeculectomy. Both were
associated with severity of initial VF defect. In this series, no significant
correlation appeared between defect progression and the last IOP, but
association between stability of VF and the amount of IOP reduction
after surgery indicate that a lower target IOP level particularly in eyes
with initially severe VF defect would, however, be needed.

56. Ophthalmology. 2004 Nov;111(11):2117-25.
Statistical evaluation of the diagnostic accuracy of
methods used to determine the progression of visual
field defects in glaucoma.
Mayama C, Araie M, Suzuki Y, Ishida K, Yamamoto T,
Kitazawa Y, Shirakashi M, Abe H, Tsukamoto H,
Mishima HK, Yoshimura K, Ohashi Y.
Most of the methods using the TD slope were
characterized by high sensitivity, the AGIS method had a
very high specificity, and those using VF sectors had
reasonable sensitivity and specificity.

57. Ophthalmology. 2002 May;109(5):1009-17.
Short wavelength automated perimetry, frequency doubling
technology perimetry, and pattern electroretinography for
prediction of progressive glaucomatous standard visual field
defects.
Bayer AU, Erb C
All three tests (SWAP, FDT, and PERG) have been successful in
detecting glaucoma eyes with a future progression of standard visual
field defects. A test battery of SWAP and PERG P1N2-amplitude
improved the power to predict these progressive defects on SAP. It
remains to be seen whether the long-term follow-up in POAG eyes will
improve the false-positive rate of SWAP and FDT.

58. Newer techniques-Need
Toidentifyglaucomatousdamagepriorto
conventionalwhite-on-whiteperimetry
BecausetraditionalAutomatedPerimetrywill
notrevealascotomauntil25-40%ofnerve
fibersaredamaged
Motionattributesofvisionareinvolvedearlyin
glaucomaandnotpickedupbyconventional
perimetry

59. Newer Perimetry Techniques
Short wave automated perimetry (S.W.A.P)
High pass resolution perimetry (H.P.R.P)
Frequency doubling perimetry (F.D.P)
Flicker perimetry
Motion perimetry
Detection and resolution perimetry

60. L-cones
M-cones
S-cones
Rods
Visual
Processing
P-Cells
K-Cells
M-Cells
Visual Acuity
HRP
Flicker
Motion
FDP
BY
Swap

62. Short Wave Automated Perimetry
Developed by Stiles
Also called Blue on yellow perimetry
Software incorporated into Humphrey’s Field
Analyser II (30-2, 24-2 programs)
Intense yellow background with blue stimulus

63. S.W.A.P.The Principle:
Concept of reduced redundancy
Stimulate one color-vision mechanism
Large blue target stimulate short wave sensitive
mechanism
Isolate the short–wave sensitive pathways

64. S.W.A.PSalient Features:
Stimulus Goldman size V,blue light (440 nm),
200 ms duration
Background-100 cd/m2 intensity yellow light
(500-700 nm)
Instrumentation and software same as W-W-
perimetry

66. S.W.A.P.
Advantages
Detectglaucomatousvisualfieldlosspriorto
conventionalwhite-on-white(W-W)perimetry
(3-5yrsinadvance)
Predictfuturevisualfeiddefectsforstandard
W-W
Morerapidglaucomatousprogressionseen,
earlier
Correlatewellwithearlyopticnervehead
changes

67. S.W.A.P
Advantages:
SWAPshownmoreextensivevisualfieldloss
thanW-Wperimetryinopticneuritisandin
diabeticmaculaoedema(blueconesaremore
susceptibletodamageindiabetes)
SWAPpathwaydeficitsprecedeluminance
pathwaydeficitsinage-relatedmaculopathy,
centralserouschoroidopathyandretinitis
pigmentosa.

68. Progressive glaucomatous loss on HFA ® and Swap (L)

69. S.W.A.P
Disadvantages:
Affectedbyabsorptionofshortwavelength
stimulibytheaginglens
Influencedbymacularpigmentabsorption
causingadepressioninthefovealpeak
Takesapprox15%longerthanW-Wperimetry,
30-2usingtheFullThresholdstrategyand
approx17%withtheFASTPACstrategy
Between-subjectnormalvariabilityisgreater
forSWAPthanforconventionalperimetry

71. Principle
M-cellneuronsub-setcomprisingathirdtoahalfof
theM-cellneurons(called"non-linear"My-cells)are
firstinvoledinglaucoma,basisforfrequencydoubling
testing(25%)
Whenalowspatialfrequencysinusoidalgratingwith
alternatingwidelightanddarkbarsundergoeshigh
temporal-frequencycounterphaseflicker,(i.e.,the
blackbandsreversetobecomewhiteandthewhite
bandsreversetobecomebecomeblackinrapid
sequence)gratingsappeartwiceasmanylight/dark
bars(spatialfrequencyappearsdoubled)calledthe
“frequencydoublingillusion”

72. Highfrequency(e.g.,20-30Hz)alternationbetween
lightanddarkbars(e.g.,1cycleperdegree)shownon
thelefttwoimagescreatesthedoublingillusion(2
cyclesperdegreegrating)shownontherightimage.
(Onecycle=light+darkbar.)

74. Non-linear M-cell neurons transmit signals related to
this illusion. These neurons are the first involved in
glaucoma, tests presenting alternate grating stimuli
attempt to identify neuron loss earlier

75. Salient Features
FDT perimetry tolerates up to 6 D of refractive
error
Not affected by external room illumination
Not affected by variations in the pupil size,the
pupil diameter should be greater than 2 mm
Instructions to the patient are also quite simple:
look at a black dot in the center of the screen
and press a button any time a grating pattern is
seen
A 10-degree square pattern is presented at 17
different locations within the central 20 * 20
degrees visual field

76. Testoptionsincludeaascreeningfield
(ScreeningC-20-1)inwhich5-degreegratings
withthreecontrastlevelsareshowat17locations
inthecentral20degreefield
FDTscreeningmodeperimetryisconsidered
abnormalwhenthefollowingarepresent:
Anydefectinthecentralfivelocations
Twomildormoderatedefectsinthe
outer 12 squares
Oneseveredefectintheouter12squares
Screeningtesttimegreaterthan90seconds
pereye
FDT screening mode perimetry

77. C-20 and N-30 for FDT Perimetry

78. N-30 FULL THRESHOLD R/E Glaucoma

79. Screening 20-1
Glaucoma---R/E

81. Full threshold
N-30
B/E Normal
Study

82. Two full threshold test options: Full Threshold N-20 and Full Threshold N-30. Each
grating is 5 degrees square, but in the N-30 test the horizontal area tested is extended to
include an extra portion of the nasal visual field, resulting in a total 30 degree horizontal
field.
FDT perimeter uses central static fixation with classic Heijl-Krakau (blind spot) fixation
checks
Defects are noted as varied gray scale depths called probability symbols
The darker the depth of gray, the less probable (based on age-related norms) that the
defect is a normal occurrence, probability varies from 5% (somewhat unlikely that the
defect is normal) to <0.5% (very unlikely that the defect is normal).

83. Reliability indices (fixation errors, false positive errors, and false negative errors) are
provided, as well as Mean Deviation (average deviation from a normal visual field based on
age-related norm) and Pattern Standard Deviation Indices (a measure of how locations
differ from each other in the overall field) for the threshold tests, similar to the indices
provided with traditional automated threshold perimetry statistical analyses.
Commercially available versions are being produced by Humphrey and Welch Allyn

84. F.D.P.
Advantages:
Short test duration( 4-5 min for full threshold)
Not affected by blur upto 6 D
Not affected by pupil size
Minimal training required

85. An example of a
superior arcuatedeficit
for Frequency
Doubling Technology
(FDT) perimetryin
comparison to the
results obtained for
standard automated
perimetrywith the
Humphrey Field
Analyzer. FDT deficit is
more extensive than
those obtained with
standard automated
perimetry.

86. Humphrey Matrix FDT
Using the
24-2 test
presentation
pattern, the
Humphrey
Matrix
yielded
these results
for the left
eye of the
same patient

87. High-Pass Resolution
Perimetry
HPRP

88. Principle
Ring-shapedstimuliarepresentedona
computerscreen
Theinnerandouterbordersoftheringare
darker,andtheareabetweenislighter,thanthe
background.theaveragecontrastofthe
stimulusisidenticaltothatofthebackground,
andismaintainedataconstantlevelwhile
stimulussizeisaltered

89. Thecomputergeneratedstimuliare"highpass
filtered";thatis,alllowspatialfrequency
informationisremoved
Thethresholdsforthedetectionofanobjectas
presentandforrecognitionofwhatitisbecome
simultaneous-ifthetargetcannotbe
recognized,itwillnotevenbeseen
Stimulusdesignisthuschosenbecauseit
correspondstocenter-surroundarrangementof
retinalganglionsreceptivefield

90. HRP
Salient Features
TestavailableinOphthimus(HighTechVision)
14targetsizesin1dbstepsareavailable
ParametersobtainedareGlobaldeviation,
Localdeviation,neuralcapacityindex,etc
TheOphthimusprovidesglobalindicesand
statisticalanalysesconceptuallysimilartothose
producedbytheHumphrey.Inaddition,the
Ophthimusprovides,asauniqueparameter,the
estimatedneuralcapacity

91. Ring Stimulus used in HRP

92. Ophthimusprovidesaprintoutthatincludes
theringtargetsizesseengraphicallyaswellas
dataabouttheoveralldeviationandfluctuation
oftheresponses
Subjectreliabilityisalsoassessed
Central30degreesvisualfieldisexamined,50
locationstested
Adaptsautomaticallytothepatient´sreaction
timeaswelltoresponsestofixationcontrol
testsand"blank"and"catch"targets
Thepatientcan,atanytime,requestapause

93. Superior Field Defect on HRP

94. HRP
Advantages
Quickerexamination(5minduration)
Excellenttest-retestreliability
Earlierdetectionofprogression
Continuous feedback helps to improve
concentration

95. HRP
Advantages:
Early detection and monitoring of glaucomatous
damage
Useful for neurophthalmologic conditions

96. HRP
Disadvantages
Limitedcommercialdistributionand
representation
Requiresnearcorrectionof6Dgreaterthan
patientsdistancecorrection,specialtriallens
needed
Useofringtargetsmakesitdifficulttoshowthe
linearnatureofdefectssuchasahemianopia
thatrespectstheverticalmidlineoranerve
fiberlayerdefectthatsplitsfixation
Theexactlocationanddimensionsoftheblind
spotarenotdelineated,thisisrarelya
significantproblem

97. Normal Examination ----Right eye

98. Glaucoma-------Right eye

99. Flicker Perimetry

100. Principle
Detectionofrapidlyflickeringstimulidepends
onthemagnocellularmechanisms(M-cells)
Tylersuggestedthatdeficitsinflicker
sensitivity(forhightemporalfreq)waslost
earlyinglaucomaandocularhypertensives
Threedifferentmethodsareemployedfor
flickerperimetry-(a)contrastmodulation
flicker,(b)criticalflickerfusion,and(c)
luminancepedestalflickerforsinusoidal
temporalstimulusmodulation.

101. Salient Features
Employslightemittingdiodes
Uniformbackgroundof50cd
Stimuliarebrieflyflickered,patientisaskedto
respondifflickerdetected
Temporalfrequencyofflickerisvariedto
determinehighestrateatwhichitisdetected
(CFF,criticalflickerfusion)

102. Flicker perimetry frequency and contrast

103. Flicker Perimetry
Advantages:
Normal aging appear later than in HFA
More resistant to optical degradation (from Blur,
cataract, etc)

104. Flicker Perimetry
Disadvantages:
Still experimental
Lack of standardization
Not too patient-friendly

105. Theconnectionbetween
theCFFFandthe
luminousthresholdin
Glaucomapatientsand
inpatientswithretinal
detachement.Asone
wouldexpect,theCFFF
showslargedeviations
inearlyGlaucoma
comparedtostandard
perimetrywhilethe
relationofthetwo
methodsinretinal
detachmentismore
linear.

106. Motion Perimetry
Principle:
M-cellsandlargeneuronsmaybedamaged
earlyinglaucomaleadingtodegradationin
motionperception
Involvesdetectionofdirectionofmotionof
smalldot/linestimulus
Detectsthemindisplacementrequiredto
detectmovement(Motiondisplacement
thresholdsarefoundelevatedinptatriskof
glaucomawithnormalvisualfields)

107. Anothertechniqueformotionperimetryuses
randompatternoflightanddarkdots,‘snow
pattern’,thisportionisthanmovedina
particulardirection,ptdetectsthedirectionof
movement
Minimumpercentageofdots(coherence)
neededtodetectthedirectionisdetermined

108. Thecentral21degreesofthevisualfieldare
tested
Tocompleteatesttakes3-8minutes
Movingstimuliareverticalbarsasdescribedin
detailbyFitzkeetal
Testrandomlyexamines16locationswithone
displacementdistance(amplitude)andthen
theprocedureisrepeatedfivetimes
Motionsensitivityscorearebasedonthe
percentageofresponsefromatotalof
84movementsover14locations(excludingtwo
closepointstotheblindspot)

109. Stimulus used for random dot coherence perimetry

110. Motion perimetryshows an inferior nasal nerve fiber bundle defect not present on
conventional automated or luminance size threshold perimetry

111. RareBit Perimetry (RBP)
RareBit Perimetry depends
on minute stimuli ("rare"
bits or "microdots") and it
replaces the conventional
thresholding approach with
simple checks for the
presence of function

113. White Noise Field Campimetry
(Aulhorn'ssnow field campimetry)
White noise field campimetry –also called snowfield
campimetry –is a method directly visualizing
scotomas, thus enabling patients to immediately
detect and interactively describe their visual field
defects (VFDs).
Scotomas are usually described as “clouds”, which are
differentiated from the surrounding normal noise field
by an apparent change in brightness perception and /
or change in noise perception.

114. Typical finding in glaucomatous visual
field loss.
Top: Conventional, automated
threshold-related slightly supraliminal
static perimetry(30°Tuebigen
Automated Perimeter), showing an
inferior arcuatenerve fiber bundedefect
Bottom: Corresponding result of white
noise field campimetry. According to
the description of the patient the noise
field defect is described as a “cloud”,
which is darker than the surrounding
normal snowfield and characterisedby a
reduced apparent movement of the dots
within this area

115. Multifocal Visual Evoked Potential
Therearetwomultifocaltechniquesthatarepresently
beingused,themultifocalelectroretinogram
(mfERG),whichmeasuresthelocalelectricalresponses
oftheretinathroughoutthecentral(26degrees
radius)visualfieldandthemultifocalvisualevoked
potential(mfVEP),whichmeasuresthelocalized
electricalresponsesfromtheprimaryvisualportionof
thebrain(occipitalcortex)forthecentral(26degree
radius)visualfield

116. Example of
correspondence of
visually evoked
potential perimetry
with standard
automated
perimetry in a
glaucoma patient
with a superior
paracentral arcuate
defect

117. Test Merit Pt
friendl
Learn Admin
-istrati
Stand
-ardis
Varia-
bility
HFA N/A No Yes Yes Yes No
SWAP YES No Yes Yes Yes No
HRP NO Yes Min Yes No Yes
FDP NO Yes Min Yes Yes Yes
Motio
n
NO - Yes Yes No No
Flicke
r
YES No Yes Yes No No

How the tests measure up?