Auto perimetry

1. INTERPRETATION OF
AUTOMATED PERIMETRY

3. Automated perimetry

Perimetry logic

Identifying field defects

Criteria for glaucomatous defects
Detecting glaucomatous progression
Advanced field defects

4. Bracketing strategy

5. Normal thresholds

¢ Mean threshold in disease-free fields
« In a given age group

» Ata given location in the visual field

« Mean normal values are stored in the
automated perimeter and compared
against patient data

6. Computers and ease of
interpretation

Sensitivity

+

Simple set of rules

y

Computer

|

Diagnosis

7. Perimeter logic (1)

+ Sensitivity determined at each location
« Normal range developed
« Normal range is arbitrary

— Includes the values of 95% of the
normal population

©Thomas R

8. Perimeter logic (2)

« ‘Abnormal’ values include the lowest
5% of those in normal individuals

¢ Therefore, 5% of normal individuals
will be labelled abnormal

‘Abnormal’ is not the same
as diseased

9. Perimeter logic (3)

+ General population — 100 tested
+ 1% glaucoma; 99% normal
* Six will have abnormal tests:

* 1 glaucoma patient
« 5 normal individuals

10. Perimeter logic (4)

* Clinic population — 100 tested
+ 30% glaucoma; 70% normal
« 33 will have abnormal tests

« 30 glaucoma patients
« 3 normal individuals

12. Before interpretation ...

... a few principles

©Thomas R

13. Rely on threshold tests

« First real evidence of glaucoma

* Detect scotoma

» Detect depression of the ‘hill’ of vision
« May predict visual loss

14. Screening tests

« Screening
* Fishing

« Fatigue

©Thomas R

15. Interpreting decibel values is
just half the challenge ...

False positives Strategy
False negatives « Experience
Fixation Technicians
Fluctuation Artefacts

©Thomas R

16. Pupil Diameter: 6.0 mm Date: 3103-2000
Visual Acuity: 6/6 Time: 3:40 PM
Age: 59

MU

17. Optimising patient performance

« Choose the most appropriate investigation
— Test pattern and strategy
« Ensure the patient is comfortably positioned
— Support feet, back and arms
— Adjust chin rest
— Cover the other eye fully
« Provide careful instructions prior to the test
« Support the patient during the test
» Give feedback on test performance

SEAGIG. Asia Pacific Glaucoma Guidelines. 2003-2004.

18. A word about the grey scale

« Never use the grey scale alone for
interpretation

* It is useful to educate the patient
and to identify false-positive
and false-negative errors

19. Test Ovation 2265

20. (o) (x)

1
(18)

(a)

(28)

22. Using the grey scale

« To educate the patient

« White scotomas with false positives

* Clover leaf pattern with false negatives

« Never interpret using the grey scale alone

23. Questions

¢ Is there a field defect?
- Is it due to glaucoma?

- Is the defect progressing?

24. Is the field abnormal?

+ Without obvious defects, it is difficult
to make a decision based on the
first field

« Repeat examinations provide
definitive information

« Never make a diagnosis based on
the visual field alone

26. D Single Field Analysis

Name: 513288 DOB: 04-08-1939

Central 20-2 Threshold Test tu

Fixation Monitor: Blindspot tim e Pupil Diameter: 2.5 mm Dato: 27-02-1995
Fixation Target: Central 0 315 ASB Visual Acuity; 6/4,5 Time: 10:40 AM

Strategy: Full Threshold RX: +4,75DS DC X Age: 56

AGE 57 ©)

FIXATION LOSSES
FALSE POS ERRORS
FALSE NEG ERRORS
QUESTIONS ASKED
FOVEA: 33 DB

TEST TIME 13:59

28. a =
CELLIER
ama ya
EA ES
AA ERA EE
WR
al: =
YY NY

-4 (7 26-16-21

433

8
5
a

29. Normal ‘hill’ of vision

\

90

©Thomas R

33. 22
1616-18
en
Haas
16-16

52
8-18-17
EEE}
an
08

m 22
2

3

Patter
Deviation

Total
Deviation

34. Examples of total and pattern

deviation plots in different situations

36. jen ae

Deviation

Total
Deviati

ft
a

ase

37. Deviation

Caen

á

39. MD -4.31dB P<5%
PSD 1.99dB
SF 1.45 dB

CPSD 1.12dB

40. —2.18 dB
4.63 dB; p<1%

1.24 dB
4.44 dB; p<0.5%

41. MD -4.31dB P<5%
PSD 1.99 dB
SF 1.45 dB
CPSD 1.12 dB

42. Indicates overall deviation MN») -2.18 dB
of the visual field from PSD 463 dB: p< 1%

normal SF 1.24 dB

CPSD 4.44 dB; p < 0.5%

43. —2.18 dB

4.63 dB; p<1%
1.24 dB
4.44 dB; p < 0.5%

44. Indicates the degree MD -2.18 dB

towhich the numbers POD 463dB, p<1%

differ from each other SF 1.24 dB
CPSD 4.44 dB: p<0.5%

45. -2.18 dB

4.63 dB; p< 1%
1.24 dB
4.44 dB; p< 0.5%

46. Global indices:
short-term fluctuation

* Intra-test error in
threshold determination

* Standard deviation of
10 predetermined
points that are each
tested twice

©Thomas R

47. Global indices: corrected
pattern standard deviation

+ CPSD is PSD corrected for the SF
-If SF is due to unreliability,
then CPSD is better

-If SF is due to pathology,
then PSD is better

48. Review of key points

MD Generalised depression
Total
ge Can suspect a scotoma
deviation plot

PSD Local i lar
Pattern ocal irregularity
ner Confirms scotoma
deviation plot

© Thomas R

49. General Reduction of Sensitivity

51. GHT, Glaucoma Hemifield Test.

GHT
Within normal limits

GHT 7
Outside normal limits

GHT

Borderline

GHT

General Reduction of Sensitivi

Low Patient Reliability
GHT

Abnormally High Sensitivity

©Thomas R

53. 128 28 28
% 2 2% 27
(27)

2 a A WD

31

Gt)

34 25 31 2
Git

3 3 0 % 20

(33)

2

3. 2
(33) (28)

a 3 2 29
(2)

210 2 2
(26)

&

54. ‘SINGLE FIELO ANALYSIS

eve! LEFT

Dos: 81-07-1548]

55. Questions

v|s there a field defect?
- Is it due to glaucoma?

- Is the defect progressing?

56. Glaucomatous defects

« Characteristics of glaucomatous defects:
— Asymmetrical across the horizontal midline*

— Located in the mid-periphery*
(5-25 degrees from fixation)

— Reproducible
— Not attributable to other pathology
— Localised

— Correlating with the appearance of the optic disc
and neighbouring areas

* Applicable to early/moderate cases.
SEAGIG. Asia Pacific Glaucoma Guidelines. 2003-2004.

57. Gr

Outside normal limits

MO -1110dB P<05%
SD 139948 P<05%
Pattern A SF 12308
Deviation CPSD 139208 P<0.5%
nun

«sx CHRISTIAN MEDICAL COLLE
er

Br VELLORE 632 001

CRE

58. ur
(Outside normal limite

11.1048 P<OSK
139908 P<05%

Pattern 4 SF 12308

Deviation CPSD 139268 P<0S%

VELLORE 632 001

>

b

59. Hr

(Outside normal limits 7

MO 111048 P<OS%
PSD 129948 P<05%

CHRISTIAN MEDICAL COLLEGE HOSPITAL

VELLORE 632 001

60. car

139948 PC05%
12308
139268 P «0,

62. Field Analysis Eye: Left

Central 30-2 Threshold Test

Fixation Monitor: Blindspot Stimulus: Il, White Pupil Diameter: 2.5 mm Dato: 27-02-1996
Fixation Target: Central Background: 31.5 ASB Visual Acuity: 6/4,5 Time: 10:40 AM
Strategy: Full Threshold Age: 56

63. a

Time: 1040 AM

64. IMAGE

Fovea: 31 dB #
MD: -6.25 dB P<O

65. 22-04-1993 Full from prior GHT: Outside normal limits

Fovea: OFF 0/17 y FP: 0/12
MD: -6.58 dB P < 0.5% PSD: 9.48 dB P <0. SF: 2.45dB P<5% CPSD: 9.07 dB P<05

66. shold GHT: Out

67. Overview

Name: MN 681604 10: 881604

Threshold Test

Threshold Graytone Threshold (dB) Total Deviation Pattern Deviation

GHT: General Reduction of Sensitivity

Only if the defects are repeatable and correlate with disc and clinical findings

68. IMAGE

pverview

Eye: Fight
ma E 10.881708 DOS: 20-08-1084
Fentral 80-2 Threshold Test

Threshold Graytone Threshold (dB) Total Deviation Pattern Deviation

18-07-2001 .S\TA-Standard @HT: Borderline

a alo

lovea: 31 dB FL:2/18
fo: -3.65 dB P<2% PSD: 2.0148

Only if the defects are repeatable and correlate with disc and clinical findings

69. Questions

v|s there a field defect?
vIs it due to glaucoma?

« Is the defect progressing?

70. Principle

» Is there a field defect?

« Is it due to glaucoma?

- Is the defect progressing?
— Compare to selected baseline
— Discard learning fields from baseline
— Recognise ‘false’ progression

©Thomas R

71. False progression

« Learning curve

¢ Long-term fluctuation
» Artefacts

» Patient factors

« Pupil size

74. Detecting change

¢ Change analysis — box plot
« Overview programme

» Glaucoma progression analysis M
(GPA™)

1. Select appropriate baseline
2. Discard learning fields from baseline

©Thomas R

75. Overview programme

+ Sequential series of fields for the same
patient over a period of time

« Has all the single field information,
including total and pattern deviation plots

« Tells us at a glance what is happening
and allows us to deduce WHY it is
happening

80. + SITA is different
from full threshold

« Can't compare
apples to oranges

« Fields may fluctuate k

81. Glaucoma Progression Analysis ™*

+ GPA™ is now in clinical use
« Change is based on the pattern deviation plot

« Compatible with both SITA and full threshold
(baseline only)

*Carl Zeiss Meditec.

©Thomas R

82. A

Glaucoma Progression Analysis

Likely Progression

See GPA printout for complete
analysis

Baseline Exams.
11-27-1997 12-15-1998
Previous Follow-up Exams:
04-18-2001 04-18-2002

4 P< 5% Deterioration

a P< 5% (2 consecutive)

A P< 5% (3+ consecutive)
Out of Range

85. |
Fovea: 36 dB ' FL:0/16

MD: -8.14 dB P<0.5% PSD: 11.15 dB P<0.5%

“18 -20/-20 -6
|
“4-5 6105 4

ED 1%

Possible Progression

Baseline Exams: 11-17-1999 11-22-2000

Che 4 P<5% Deterioration
$4 2% A P<5% (2 consecutive)
81% À P<5% (3+ consecutive)
B<05% X Out of Range

Glaucoma Progression Analysis (GPA)

HFA Il 750-1072-Rev. A10/3.5

© 2003 Carl Zeiss Meditec

© Thomas R

86. 01-16-2002 Sa een GHT: Outside normal limits A
| |
| | |
CTI LI A LE) aali
CEE 45-80 4 5 had la ba
3 47-2458 15-2 -3 X4 4 ak 4
16-2911 2 XXAAG|

0321/07 3
| |
0 042 020 Poe
21 02 00 aa
els
|
|

0112
|

Fovea: 26dB M FL:0/0 FP. 3%
MD:-11.14dB P<05% PSD: 1053dB P<05% Likely Progression

Baseline Exams: 11-17-1999 11-22-2000

1
|

Glaucoma Progression Analysis (GPA |

1: 5% P < 5% Deterioration Ñ d |
|

942% P< 5% (2 consecutive) |
BY P <5% (3+ consecutive) | HFA II 750-1072-Rev. A10/3.5
805% Out of Range

© 2003 Carl Zeiss Meditec © Thomas R

89. 05-15-2001 SITA-Standard GHT: Outside normal limits

+++ Low Test Reliability ***

ok

Fovea: 3148 à 6/16 xx
MD: -4.16 dB P< 1% PSD: 4.1648 P<05%

01-16-2002 SITA-Standard — GHT: Outside normal limits

ES

3.4 mm

L
|
|

Fovea: 2748 M FL: 9/16 xx
MO: -4.91 dB P<0.5% PSD: 3.2148 P< 1%

Baseline Exams: 11-17-1999 11-22-2000

<5% 4 P €5% Deterioration
w<2% A P<5% (2 consecutive)
20% A P<5% (3+ consecutive)

m<os% X Out of Range

Glaucoma Progression Analysis (GPA)

u HFA Il 750-1072-Rev. A10/3.5
© 2008 Carl Zeiss Meditec

90. Diagnosis of visual field
progression

« Different for research purposes
— Set criteria in isolation
« Clinical follow-up scenario
— Other criteria (IOP, disc changes) to consider
— A corresponding repeatable change is sufficient
— If in doubt, REPEAT
« Baseline fields are not constant
— Select accordingly

©Thomas R

91. —

¡orcos Fresse)

MO-11.7148 P<OSK — PSD. 20

Fos: 2008
Mo -8.15 8 P<05%

93. Advanced field defect

94. vor Te: 820M

ocx Ages

No man Pose
s 1006

cuasi MEDICAL COLLEGE N

99. Defect Depth (dB) Threshold (dB)

= Within 4 dB of Expected CHRISTIAN MEDICAL COLLEGE
Central Reference: 33 dB

Size V target: macular split

100. Recent developments: SITA

« Asks smart questions
« Gold standard

« More abnormal points on pattern
deviation

« Shallower defects
* Significant because of less variability

103. Applying the skills

105. Automated perimetry: warning

Sophisticated techniques and elaborate
data printouts should not seduce us into
a false sense of security or a misplaced
belief in the validity or reliability of
automated perimetry*

*Zalta AH. Ophthalmology 1989; 96: 1302-11.

106. INTERPRETATION OF
OCTOPUS FIELDS

107. Parameter

Test parameters — Octopus vs.
HFA

Octopus 300

HFA 700 series

Bowl type

Direct projection

Aspherical bowl

Background luminance

10 cd/m? (31.4 asb)

10 cd/m? (31.5 asb)

Stimulus size
Stimulus duration
Luminance for 0 dB

Goldmann Ill and V
100 ms
4800 asb

Goldmann |-V
200 ms
10,000 asb

Measuring range

0-40 dB

0-40 dB

Test strategies

4-2-1 dB bracketing
strategy

Dynamic

Tendency oriented
perimetry (TOP)

4-2 dB bracketing
strategy

SITA standard

SITA fast

Fankhauser F et al, Automated Perimetry: Visual Field Digest. 5" Edn. Kóniz: Haag-Streit AG, 2004.

108. [[Credit line to be added]]

109. Octopus global indices

MS

MD

LV

SF

Mean sensitivity

— Average of all measured values

Mean defect

— Average of all values corrected for age
Loss variance

— Equivalent to PSD

Short-term fluctuation

+ CLV ‘Corrected’ loss variance

* RF

— Equivalent to corrected PSD
Reliability factor

110. Is the visual field abnormal?

° Octopus criteria for a visual field defect’
— MD greater than 2 dB
— LV greater than 6 dB

— At least 7 points with sensitivity decreased
by = 5 dB, three of them being contiguous

¢ How do these compare to HFA criteria?

1. Morales J et al. Ophthalmology 2000; 107: 134-42.

111. Oc

Y
IMAGE

112. Comparison of Octopus and
HFA fields from a single patient

113. GLAUCOMA LAB
DR RP CENTRE, AIM

6TH FLOOR
NEW DELHI

10%
Birihdat

Ag

Rett. S
Aculy
10P:
Diagnosti
Patient fk

Single Field Analysis

Pupilo)
Time
duration:
Program / Code:
s / Phases:
Method:
Test targat / duration
Background
$ Questions / Repetit
# Catch tials:

Program Fi

opus ExDal

Righ(OD) /3
$ AM

315
6,neg 1

Ce 1

Feat Moni:
Faken Tams
Fon’

Pipa Drm
feu ay
Re

ex Date
ext Tae

Das:
tae:

114. IMAGE

115. Phase |
59
21.8
68
46.6

Phase 2
59

18.6
10.1
73.2

116. GHT Outside normal limits
MD -7.58 dB; p< 0.5%

PSD 6.30 dB; p< 2%
SF 2.27 dB; p< 10%
CPSD 5.75 dB; p< 1%