Visual field testing and interpretation

Different techniques of kinetic and static perimetry

1. VISUAL FIELD
TESTING
AND
INTERPRETATION
HIRA NATH DAHAL

2. PRESENTATION LAYOUT
•INTRODUCTION ON VISUAL FIELD
•NORMAL LIMITS OF VISUAL FIELD
•SHORT OVERVIEW ON HISTORY OF VF
•TERMINOLOGIES RELATED TO VF
•VISUAL FIELD TESTING METHODS
•KINETIC, STATIC
•INTERPRETATION OF VF REPORTS

3. INTRODUCTION
VISUAL FIELD
•THE VISUAL AREA THAT IS
PERCEIVED
SIMULTANEOUSLY BY A
FIXATING EYE.

4. RETINA VS VISUAL FIELD
Optic disc
Nasal to the fovea – Seen in
temporal VF as a Blind spot

5. TRAQUAIRS FIELD OF
VISION

6. HILL OF VISION

7. Normal limits of visual field

8. SHORT HISTORY OF VISUAL
FIELD
•IN B.C 150, PTOLEMY: USED SOME FORM OF PERIMETRIC
DEVICE TO MEASURE EXTEND OF VF
•FIRST CLINICAL INVESTIGATION OF VF DEFECT –
HIPPOCRATES IN 5
TH
CENTURY, HEMIANOPIC FIELD DEFECT
•FINALLY IN 1604 KEPLER EXPLAINED THE PRINCIPLE OF
SIGHT IN TERM OF AN INVERTED RETINAL IMAGE –
–AN STAGE FOR MODERN INVESTIGATION OF VF

9. HISTORY….
•IN 1666, MARIOTTE DISCOVERED
PHYSIOLOGICAL BLIND SPOT
•IN 1801, YOUNG STATED THE NORMAL
EXTEND OF VF OF AN EYE
•VON GRAEFE MAPPED OUT BLIND SPOT,
CENTRAL SCOTOMAS, CONSTRUCTION OF
ISOPTER.
•INTRODUCED VF IN CLINICAL MEDICINE
FOR THE FIRST TIME
•UNTIL 1869, FOERESTER INVENTED ARC
PERIMETER, TILL THEN VF PLOTTED ON
FLAT SURFACE
Thomas
Young
Von
Graefe

10. HISTORY……
•IN 1880, BJERRUM DEVELOPED
TANGENT SCREEN
•IN 1940, MARC AMSLER
INTRODUCED AMSLER GRID
•IN 1939 SLOAN DESCRIBED
STATIC PERIMETRY
•IN 1945 GOLDMAN
PERIMETER
•IN 1960 TUBINGER- MANUAL
TESTING OF BOTH STATIC AND
KINETIC PERIMETER
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11. FEW TERMINOLOGIES
•THRESHOLD: THE WEAKEST TEST STIMULUS THAT IS JUST
VISIBLE IN A PARTICULAR LOCATION UNDER THE SPECIFIC
TESTING CONDITION.
•VARIES ACROSS THE VISUAL FIELD.
•SENSITIVITY: MOST SUBTLE CHARACTERISTICS OF A STIMULUS
THAT IS VISIBLE AT A SPECIFIC POINT IN SPACE.
•FIXATION: THAT PART OF VISUAL FIELD CORRESPONDING TO
FOVEA CENTRALIS.

12. TERMINOLOGIES…
•ISOPTER:
•LINE CONNECTING ALL POINTS IN THE VISUAL FIELD WITH THE
SAME THRESHOLD ( FOR A GIVEN TEST SPOT)
•BOUNDARY BETWEEN AREA OF VISIBILITY TO THE AREA OF NON-
VISIBILITY FOR A PARTICULAR STIMULUS

13. TERMINOLOGIES…
•SCOTOMA: LOCALIZED DEFECTS\DEPRESSIONS SURROUNDED BY
NORMAL VISUAL FIELD.
•ABSOLUTE: DEFECT THAT PERSISTS WHEN THE MAXIMUM
STIMULUS IS USED E. G BLIND SPOT.
•RELATIVE : DEFECT THAT IS PRESENT TO WEAKER STIMULUS BUT
DISAPPEARS WITH BRIGHTER STIMULUS.

14. LOCATION OF VISUAL
FIELD DEFECTS
•CENTRAL
•5 DEGREES OR LESS FROM THE POINT OF FIXATION
•PARACENTRAL
•>5 DEGRESS – 30 DEGREES
•CEACAL, PARACEACAL, PERICEACAL
•CENTROCECAL
•PERIPHERAL
•>30 DEGREES

16. DESCRIPTIVE COMPONENTS OF
VF DEFECTS
•MONOCULAR DESCRIPTIONS
–DENSITY
•ABSOLUTE (NO VISUAL SENSATION) OR RELATIVE (DEPRESSED
VISUAL SENSATION)
–AREA
•GENERAL OR LOCAL
–SHAPE
•SECTORIAL (HEMIANOPIC) OR NON-SECTORIAL (REGULAR OR IRREGULAR)
–EXTENT
•TOTAL OR PARTIAL
–POSITION
•RT. OR LT. . TEMPORAL, NASAL, SUPERIOR, INFERIOR

17. DESCRIPTIVE COMPONENTS
OF VF DEFECTS
•Binocular description
• Laterality
•Unilateral or bilateral (homonymous/heteronymous)
•Equalness
•Congruous or incongruous
•Additional description
•Awareness
•Positive (defect perceived) or negative (defect not perceived)

19. SIGNIFICANCE OF VISUAL
FIELD TESTING
•FIND OUT THE EXTENT OF VF
•TO DIAGNOSE AND DETECT DISEASES AS WELL AS EXTENT OF
DAMAGE CAUSED IN VF BY THE DISEASE
•TO LOCATE POSSIBLE LESION IN NEUROLOGICAL DISORDER
•TO FIND OUT THE PROGRESSION OF DISEASES

20. VISUAL FIELD TESTING
METHODS/TOOLS
•CENTRAL
•AMSLER GRID: 20
0
•TANGENT (BJERRUM SCREEN): 30
0
•GOLDMANN
•AUTOMATED (OCTOPUS / HUMPHERY) :30
0
•PERIPHERAL
•CONFRONTATION
•GOLDMANN
•AUTOMATED 90
0
PROGRAMME

21. PERIMETRY
•SYSTEMATIC MEASUREMENT OF VF BY THE USE OF A
PERIMETER
•MODERN PERIMETER
•CONSIST OF A BOWL POSITIONED AT A FIXED DISTANCE FROM
THE EYE,
•ENABLE THE CONTROLLED PRESENTATION OF STIMULI WITH IN THE
BOWL
•ENABLES ASSESSMENT OF THE VISUAL FUNCTION THROUGH OUT THE
VISUAL FIELD
•DETECTION & QUANTIFICATION OF DAMAGE TO THE VISUAL FIELD
•MONITORING THE CHANGE OVER A TIME

22. PERIMETRY TYPES
Kinetic Static
• measures extent of visual field
by plotting isopters ( locus of
retinal points having same
sensitivity)
•Stimulus moves from non-
seeing to seeing area.
•Result depends upon the
experience of the operator.
• e.g, Goldman perimetry,
confrontation, Tangent screen,
Arc perimetry
• measures the sensitivity of
each retinal points.
•The stimulus is stationary but
increases in luminance.
• Mostly automatic, very little
role of the operator.
•e. g, Automated perimetry,
Goldman perimetry

23. GOLDMAN PERIMETRY
•THE MOST WIDELY USED INSTRUMENT FOR MANUAL
PERIMETRY.
•HAS A CALIBRATED BOWL PROJECTION INSTRUMENT
•WITH A BACKGROUND INTENSITY OF 31.5 APOSTILBS (ASB),
•TEST TARGETS: DOTS
•VARYING SIZE AND ILLUMINATION

24. PERIMETRY BOWL
•BACKGROUND
LUMINANCE
31.5 ASB
RADIUS OF THE BOWL
30 CM
Patient side

25. GOLDMANN TARGETS
•THE STIMULI (DOT) USED TO PLOT AN ISOPTER DENOTED
BY
• ROMAN NUMERAL, A NUMBER, AND A LETTER.
•ROMAN NUMERALS = 0 TO V (SIZE)
•NUMBER = 1 TO 5 (LUMINANCE) USE OF FILTER
•ALPHABET = A TO E ( ‘’) USE OF FILTER
V4e , I4e, IV3e

26. GOLDMANN PERIMETRY: ROMAN
NUMERAL
•SIZES OF STIMULI [0...V SCALE]
•EACH SIZE INCREMENT EQUALS
•A TWOFOLD INCREASE IN DIAMETER AND A FOURFOLD
INCREASE IN AREA.

Diameter (mm) Area (mm
2
)
0 0.28 1/16
I 0.56 ¼
II 1.13 1
III 2.26 4
IV 4.51 16
V 9.03 64

27. TARGET ILLUMINATION
•LUMINANCE SETTINGS
•EXPRESSED IN UNITS CALLED APOSTILBS
(CANDELA/M
2
)
•2 SETS OF FILTERS – 5 EACH
•10 STEPS
• STANDARD VS FINE SETTINGS
•(1...5 AND A...E SCALES)
•1, 2, 3, 4 SETTINGS REPRESENT 0.5 LOG UNIT
CHANGES = 5 DB
• A, B, C, D AND E SETTINGS REPRESENT 0.1 LOG
UNIT CHANGES = 1DB

28. TARGET RANGE IN
GOLDMANN
•MORE THAN 100 COMBINATIONS OF SIZE AND INTENSITY OF TEST
TARGETS ARE POSSIBLE
•BUT ONLY A FEW ISOPTER ARE NEEDED TO DEFINE THE VISUAL FIELD.
•SIZE “0” GENERALLY IS OMITTED
• BECAUSE RESULTS OF THE PLOTS ARE INCONSISTENT.
•THE FINE-INTENSITY FILTER IS USUALLY SET TO THE LETTER “E”
•WHICH ELIMINATES THE SMALL-INCREMENT LIGHT FILTERS.
•TEST TARGET : DENOTED BY – SIZE + (STD. + FINE) LUMINANCE
•EG: V4E, I4E, II3E

29. SOME INTERESTING FACTS
•A CHANGE OF ONE NUMBER OF INTENSITY
– IS ROUGHLY EQUIVALENT TO A CHANGE OF ONE ROMAN
NUMERAL OF SIZE I.E. III4E = IV3E
•ISOPTER PLOTTED WITH TARGETS OF EQUAL SUM OF
–ROMAN NUMERALS (SIZE) & NUMBER (INTENSITY)
•ARE CONSIDERED EQUIVALENT.
–FOR EXAMPLE,
•THE I4E ISOPTER IS ROUGHLY EQUIVALENT TO THE II3E ISOPTER.
•I + 4 = 5, II + 3 = 5

30. STANDARD VF PLOT OF RE

31. REQUIRED EQUIPMENT FOR VF
MAPPING
•GOLDMANN BOWL PERIMETER
•LENS HOLDER
• RECORDING PAPER
•COLORED MARKERS
•PATCH FOR MONOCULAR TESTING

32. GOLDMANN PERIMETER
Pantoscopic handle
Horizontal cut
Patient Side (Bowl)

33. GOLDMANN PERIMETER
Patient Side (Bowl)
Fixation target
Chin rest
Head rest
Len Holder

34. GUIDELINE TO PLOT
•FIRST DEMONSTRATE THE PROCEDURE
TO PATIENT
•BY STATICALLY PRESENTING LARGE
TEST
GENERAL RULES FOR PLOTTING
“ISOPTERS”
•AN ISOPTER IS MAPPED FOR THE
PARTICULAR STIMULUS SIZE AND
INTENSITY

•MOVE FROM NON-SEEING TO SEEING
WHILE PRESENTING STIMULUS
•MOVE AT A RATE OF 5 DEGREES PER
SECOND INSIDE
•PRESENT KINETICALLY EVERY 15
DEGREES INTERVAL

35. GUIDELINES FOR PLOTTING
•BEGIN IN THE FAR PERIPHERY AND KINETIC PLOT ISOPTER IN ALL
MERIDIANS
•USE A V4E, I-3E , I-2E OR TARGET (DEPENDING UPON AGE
•PLOT THE BLINDSPOT
•ONLY 4 MERIDIANS ARE REQUIRED( MORE IF IRREGULAR OR
LARGE)
• USE THE I-4E FOR THE BLIND SPOT
•WITHIN ISOPTER OF I-2E OR I-3E

36. GUIDELINES
•CENTRAL STATIC TEST WITH I-2E
• EXPLORE FOR ANY SCOTOMAS
•KINETIC PLOT WITH I-3E STIMULUS ONLY IN SUSPECTED DEFECT AREA
•STATIC TEST BETWEEN I-3E AND I-2E ISOPTERS
WITH THE I-3E STIMULUS (SCOTOMA SEARCH)

37. GUIDELINES
•SPECIAL CASE PLOTS
•GLAUCOMA SUSPECTS
•PLOT MORE POINTS ALONG THE NASAL EDGE OF THE ISOPTER
• PLOT APPROXIMATELY
•EVERY 3-5 DEGREES,
•15 DEGREES ABOVE AND BELOW THE HORIZONTAL RAPHE
REPEAT FOR CENTRAL, INTERMEDIATE AND PERIPHERAL PLOTS
•SUSPECTED NEUROLOGICAL LESIONS
•PLOT MORE POINTS ON EITHER SIDE OF THE VERTICAL MERIDIAN
•REPEAT FOR CENTRAL, INTERMEDIATE AND PERIPHERAL PLOTS

38. RECORDING
•ALL RECORDING SHOULD BE
DONE ON THE GOLDMANN
RECORDING PAPER
•PATIENT NAME,
•DATE,
•RX USED,
•PUPIL SIZE,
•EYE TESTED AND
•PATIENT COOPERATION / FIXATION
•INDICATE THE TARGET SIZES
USED IN THE BOTTOM RIGHT HAND
BLOCK (COLOR MARKER)

39. COLOR CODING OF ISOPTERS
• I-2E BLUE
• I-3E ORANGE
•I-4E RED
•II-4E GREEN
•III-4E PURPLE
•IV-4E BROWN
•V-4E BLACK

40. EXPECTED FINDINGS FOR
NORMAL ISOPTERS
•PATIENTS UNDER 50 YEARS OF AGE
I. PERIPHERAL I-4E (SIZE=SAME, BRIGHTER LUMINANCE)

II. INTERMEDIATE I-3E
III. CENTRAL I-2E (SIZE=SAME, DIMMER LUMINANCE)

41. EXPECTED FINDINGS FOR
NORMAL ISOPTERS
•PATIENTS 50 YEARS OR OLDER

I. PERIPHERAL II-4E (SIZE=LARGER, BRIGHTER LUMINANCE)
II. INTERMEDIATE I-4E
III. CENTRAL I-2E OR I-3E (SIZE=SMALLER, DIMMER LUMINANCE)

42. INTERPRETATION
•THE VISUAL FIELD IS CONSIDERED ABNORMAL IF:
–THE THRESHOLD VALUES ARE SIGNIFICANTLY BRIGHTER (0.5
LOG UNITS OR MORE) THAN THE EXPECTED VALUES
AND / OR
–SCOTOMAS OR DEPRESSIONS ARE PRESENT

43. SOME VISUAL FIELD
DEFECTS

44. SOME VISUAL FIELD DEFECTS

45. BITEMPORAL HEMIANOPIA
Right eye Left eye

46. AUTOMATED PERIMETRY
( STATIC)
•MACHINE CONSTRUCTED ALONG THE BASIC LINES OF A
GOLDMAN PERIMETER + SOPHISTICATED SOFTWARE
PROGRAMS.
•KEY REASON FOR INCREASED INTEREST IN AUTOMATED
PERIMETRY HAS BEEN DUE TO THE STANDARDIZATION
AUTOMATED PERIMETRY ALLOWS.

47. AUTOMATED PERIMETRY
•VISUAL THRESHOLD IS MEASURED AT A SERIES OF FIXED
POINTS IN THE VISUAL FIELD.
• THE BRIGHTNESS OF THE TEST SPOT IS VARIED, BUT NOT
ITS LOCATION.
•THRESHOLD IS USUALLY PLOTTED RELATIVE TO NORMAL
FIELDS, TO REVEAL DEFECTS

48. AUTOMATED PERIMETRY

49. AUTOMATED PERIMETRY
•HUMPHREY:
•OCTOPUS:

50. THRESHOLD
DETERMINATION
Frequency of seeing curve

51. THRESHOLD
DETERMINATION
28dB
24 dB
32 dB
30 dB
29 dB
0 dB brightest stimulus

52. THRESHOLD
DETERMINATION
•AGE MATCHED NORMAL DATA ARE USED TO COMPARE
PATIENT’S DATA
•NORMAL RANGE DETERMINED BY
•SENSITIVITY OF EACH RETINAL POINTS 10,000 INDIVIDUALS
•UPPER 95% AS NORMAL
•LOWER 5% AS ABNORMAL

53. TESTING STRATEGIES
•OCTOPUS
•NORMAL
•DYNAMIC
•TOP ( TENDENCY ORIENTED PERIMETRY)
•HUMPHREY
•SITA (SWEDISH INTERACTIVE THRESHOLD ALGORITHM)
•SITA FAST
•FULL THRESHOLD

54. DIFFERENCE BETWEEN OCTOPUS AND
HUMPHREY (TEST PARAMETERS)

55. FACTORS AFFECTING
AUTOMATED PERIMETRY
•BACKGROUND LUMINANCE
•STIMULUS SIZE
•FIXATION CONTROL
•REFRACTIVE ERRORS
•CATARACTS AND OTHER MEDIA OPACITIES
•MIOSIS
•FACIAL STRUCTURE
•FATIGUE
•EXPERIENCE OF A PERIMETER

56. VALIDITY OF THE TEST
•FALSE POSITIVE RESPONSE
•> 20% UNRELIABLE
•FALSE NEGATIVE
•>20% UNRELIABLE
•SHORT TERM FLUCTUATION
•1-3 DB NORMAL FLUCTUATION
•FIXATION LOSS
•>33% UNRELIABLE

57. CHOOSING AN
APPROPRIATE PROGRAM
EXAMINATION PROCEDURE
TEST PROGRAM(G1, G2, 32, M2)
+
TEST STRATEGY (NORMAL, DYNAMIC, TOP)
+
PERIMETRY METHOD( W/W, FLICKER, B/Y, KINETIC)

58. PROGRAMS
G1/G2
•CENTRAL 30 DEGREE
•GLAUCOMA SCREENING
•59 POINTS
•LOCATIONS MORE CLOSELY WITH TOPOGRAPHY OF RETINA
(IN AREAS OF CONCERN OF GLAUCOMA)
•2.8 DEG SPACING

59. PROGRAMS
32 ( GENERAL EXAMINATION)= 30-2 IN HUMPHREY
•INTRODUCED WITH EARLY AUTOMATED PERIMETRY
•76 TEST LOCATIONS
•WIDE SPACING (6 DEGREES) ( NOT APPROPRIATE FOR
GLAUCOMA)

60. PROGRAMS
MACULA PROGRAM(M2)
•CENTRAL AND PARACENTRAL VISUAL DEFECTS IN
NEUROLOGICAL AND MACULAR PROBLEMS
•CENTRAL 10 DEG
•56 TEST LOCATIONS
•SPACING 2 DEGREES
•0.7DEG SPACING IN THE MACULA

61. PROGRAMS
LVC (CENTRAL LOW VISION)
•TO TEST HOW MUCH SENSITIVITY IS REMAINED IN THE
CENTRAL FOVEAL AREA.
•77 LOCATIONS
•30 DEGREES
•END STAGE GLAUCOMA

62. STRATEGIES
•NORMAL STRATEGY
•STANDARD
•4-2-1 BRACKETING PROCEDURE
•10-15 MIN
•EARLY AND SHALLOW DEFECTS
•YOUNGER PATIENTS ( GOOD CONDITION IN ANSWERING THE
QUESTION TILL THE END OF A LONG PROGRAM)

63. STRATEGIES
•DYNAMIC STRATEGY
•ONE THRESHOLD CROSSING
•SMALL STEPS IN REGIONS WITH NORMAL SENSITIVITY AND
LARGE TOWARDS DEPRESSED FIELD
•TEST DURATION REDUCED BY TWO
•ESPECIALLY WHEN FOCAL DEFECTS ARE EXPECTED

64. STRATEGIES
•TOP ( TENDENCY ORIENTED PERIMETRY)
•LIGHT SENSITIVITY OF THE RETINAL IS INTERRELATED RATHER
THAN HAVING AN INDIVIDUAL VALUE
•2 MINUTES
•FOR PATIENTS WITH DEPRESSED FIELDS, FOR CHILDREN, ELDERLY
ONES WHO ARE NOT CAPABLE OF FINISHING A LONGER
EXAMINATION

65. INTERPRETATION OF
RESULTS

67. DIFFERENT ZONES

68. GREYSCALE

69. VALUE TABLE

70. COMPARISON /CORRECTED
COMPARISON(TOTAL AND PATTERN
DEVIATION)

72. PROBABILITY PLOTS

73. CUMULATIVE DEFECT CURVE

75. GLAUCOMA HEMIFIELD TEST
•5 SECTORS IN THE UPPER FIELD ARE COMPARED TO FIVE
MIRROR IMAGES IN THE LOWER
•IF VALUE IN TWO SECTORS DIFFER TO AN EXTENT THAT FOUND
IN
•<0.5% OF THE NORMAL POPULATION ( HIGHLY SENSITIVE)
•<1% OF NORMAL POPULATION (OUTSIDE NORMAL LIMIT)
•<3% OF THE NORMAL POPULATION (BODERLINE)
•<5% OF THE NORMAL POPULATION ( CAN BE A NORMAL PLOT)

77. GLOBAL INDICES
OCTOPUS
•MEAN SENSITIVITY (MS)
•MEAN DEVIATION (MD) (–
2DB TO +2DB)
•LOSS VARIANCE (LV) (0-
6DB)
•CLV(0-4DB)
•SF (1.5DB- 2.5DB)
•RF < 15%
HUMPHREY
•GHT
•MEAN DEVIATION
•PSD
•CPSD
•SF

78. OCTOPUS CRITERIA FOR VISUAL
FIELD DEFECT§

79. HFA CRITERIA FOR VF LOSS
•PATTERN DEVIATION PLOT

81. RECENT ADVANCES IN AUTOMATED
PERIMETRY•GOLDMAN KINETIC MODULE
•HIGH-PASS RESOLUTION PERIMETRY - USES THIN RINGS INSTEAD
OF SPOTS
•SHORT WAVELENGTH SENSITIVE PERIMETRY - BLUE ON YELLOW
FOR S CONES
•FLICKER PERIMETRY - FLICKERING TARGETS INSTEAD OF STATIC
FLASHES
•AULHORN'S SNOW FIELD CAMPIMETRY - USES TV “SNOW” AND
POINTING
•MOTION PERIMETRY - DETECT MOVING TARGETS INSTEAD OF
FLASHED ONES
•RAREBIT PERIMETRY- USES VERY SMALL, BRIGHT SPOTS
•PUPIL PERIMETRY - MEASURES PUPIL RESPONSES INSTEAD OF
SUBJECT
REPORTS
•MULTIFOCAL VEP - MEASURES CORTICAL EVOKED POTENTIALS
INSTEAD OF
SUBJECT REPORTS

82. SUMMARY
•PRINCIPLE OF KINETIC AND AUTOMATED PERIMETRY
•APPROPRIATE SELECTION OF VISUAL FIELD TESTING FOR A
PARTICULAR PATIENT
•ACCURATE INTERPRETATION OF VF REPORTS