This document discusses visual field examination and interpretation of automated perimetry in glaucoma. It provides details on the physiology of the visual field and different types of visual field defects. It also describes various methods of visual field examination including kinetic and static perimetry as well as clinical techniques. Automated perimetry devices like Humphrey Field Analyzer and their advantages are discussed. Important aspects of visual field test interpretation including reliability indices, total and pattern deviation plots, and global indices are summarized.

1. VISUAL FIELD EXAMINATION
AND
INTERPRETATION OF AUTOMATED
PERIMETRY IN GLAUCOMA
DR PAAVAN KALRA
DEPARTMENT OF OPHTHALMOLOGY
S P MEDICAL COLLEGE
BIKANER

2. VISUAL FIELD
• That part of environment wherein a steadily fixating eye can
detect visual stimulus.
• BASIS - presence of Photoreceptors and corresponding
visual pathways upto the periphery of retina away from point
of fixation i e fovea.
• IMPORTANCE – Reflects topographic sensitivity of various
foci on retina and corresponding visual apparatus.
Resolution – Acuity
differential light sensitivity and contrast
colour
flicker
motion

3. PHYSIOLOGICAL BASIS

4. VISUAL ACUITY

5. DIFFERENTIAL LIGHT SENSITIVITY
Basis of most modern visual field examination methods
TRAQUAIR – “HILL OF VISION IN THE SEA OF DARKNESS”

6. FACTORS
Apparent size of spot – real size
-- distance from eye
Duration of stimulus
Background illumination
Stimulus intensity
Contrast
Colour
Patient factors
Light / dark adaptation
Vision
Refractive status
Education , attentiveness, cooperation

7. Stereoscopic field

8. PHYSIOLOGICAL BLIND SPOT
Corresponding to optic nerve head
15 deg temporal to point of fixation
Span – 5 deg horizontal
-- 7 deg vertical
Two thirds below the horizontal
meridian

9. COLOUR FIELD
• Point at which passing from periphery to centre, the
colour first becomes evident
• Peripheral to the limit, the object is perceptible but
appears grey
• First red and green are used followed by blue and yellow
• Extent of field for objects of same size and intensity
white > yellow > blue > red > green

10. VISUAL FIELD DEFECTS

11. • SCOTOMA : focal region of abnormally decreased
sensitivity surrounded by an area of normal sensitivity
ABSOLUTE
RELATIVE
POSITIVE
NEGATIVE
• DEPRESSION : is an area of reduced sensitivity without
a surrounding area of normal sensitivity
appears as denting of isopters

12. • Generalized depression
(both peripheral and central contraction)
e g cataract
• Peripheral Contraction – retinitis pigmentosa
• Temporal contraction - age

13. • Hemifield defect :
B/L - Hemianopias
homonymous
heteronymous
• Altitudinal defect

14. • Central scotoma
• Pericentral
• Centrocaecal scotoma
• Arcuate scotomas
Seidel scotoma
paracentral scotoma
Bjerrum scotoma
• Nasal step
• Ring – double arcuate
• Split fixation
• Barring of blind spot

16. EXAMINATION METHODOLOGY

17. KINETIC
• Test object of particular size and intensity is passed from
non seeing area to seeing area along a particular
meridian at the rate of 3 – 5 deg per sec
• Repeated every 15 – 30 deg
• To find points in the visual field of equal sensitivities –
ISOPTER (Groenouw) marking
• Intensity and size of stimulus is varied to mark various
isopters
• Thus 2 D Contour map of the hill of vision is made
• Extent of scotomas and blind spot marked from inside
out

18. STATIC
• The location, size and duration of stimulus is kept constant
and the luminance is gradually increased until seen
• Actual estimation of sensitivity ( THRESHOLD ) of each
point is made out
• SUPRA THRESHOLD stimulus used for screening
-------------------------------------------------------------------------------
IMPORTANT :
one eye is tested at a time, other is occluded
fixation of the patient has to be steady and is
monitored throughout the test
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19. CLINICAL METHODS
GROSS DEFECTS

20. PROJECTION OF LIGHT
In patients with very poor vision –> HM + to PL +
e g dense cataracts
-dark room, other eye occluded
-patients are constantly instructed to look straight to avoid
tendency to deviate eye towards light source
-light shown onto 4 quadrants from 30-50 cm and switched
on and off
-Patient tells about the direction of light source
Accurate in all quad
Inaccurate in some quad
Inaccurate in all quad

21. HAND IDENTIFICATION
Other eye is occluded
Patient fixates on the nose of
examiner
Examiner keeps both hands on either
side of eye 50 cm away
One hand absent or indistinct –
hemianopic defect
Either palms or fingers of both hands
missing / faint – altitudinal defect

22. FINGER COUNTING
Varying no of fingers are held in each
quadrant, 1 m and 45 deg from
fixation
If unable to count, fingers are brought
closer to fixation, until patient sees
(kinetic)

23. RED DESATURATION
Can be confirmed kinetically
Patient has to indicate when color
appears to change
Can also be used to compare the
two eyes in case of optic
neuropathy

24. CONFRONTATION
(kinetic)
Patient‟s and examiner at same level
Compares the visual field of eye of
patient with opposite eye of the
examiner in a plane perpendicular
to line of gaze
Red pin is particularly useful for
neurological cases
GROSS PERIMETRY
(kinetic)
Follows facial contour

25. AMSLER GRID
For Central 10 deg ( static )
Other eye occluded
Near correction given
Chart at held 28-30 cm – each small square subtends angle of 1
deg
Patient fixates at central dot – tells whether all corners are seen
simultaneously and about lines- parallel, distorted, missing
Can be used for mapping blind spot – patient fixates at edge of
grid

26. EQUIPMENTS

27. PERIMETRY
Examination and quantification of visual
field by using stimulus of various
sizes, intensities and colours

28. ARC PERIMETERS
eg LISTER‟s PERIMETER
• Only kinetic
• Peripheral charting

29. BJERRUM’s SCREEN ( CAMPIMETRY)
• Patient sits at 1 or 2 m from flat screen
• Kinetic and static
• For central 30 deg only
• Done under subdued lighting

30. GOLDMANN’s PERIMETER
• Bowl type
• Standardization
• Both kinetic and static
• Peripheral as well as central

31. AUTOMATED PERIMETRY
standard automated perimetry
HUMPHREY FIELD ANALYZER
OCTOPUS
• STATIC perimetry
• Measurement of threshold values
• STATPAC (HFA)- Comparison to normative data
• Inbuilt program for analysis – diagnosis and progression

32. ADVANTAGES
• Removal of examiner variability
• More sensitive to subtle field defects
• Reproducibility
• Retests abnormal points automatically
• Gives reliability parameters like
fixation monitoring – HEIJL KRAKAU method
Gaze tracking
False positive
False negative

33. SHORT COMINGS
• EXPENSIVE
• Learning curves
• Difficult to follow by older debilitated patients especially
neurological problems
• Not infallible – only 1 % of field is actually examined
• Diagnosis and management decisions based on
correlation with other clinical findings
A well performed tangent screen examination is better than
poorly carried out automated perimetry
In neurological patients, clinical methods may be the only
possible assessment techniques

34. • WHITE ON WHITE
• BACKGROUND ILLUMINATION - 31.5 asb
• STIMULUS SIZE – GOLDMANN - III
• DURATION OF SPOT EXPOSURE 0.2s

35. PROGRAMS / PATTERNS
30-2 – gold standard
24-2
10-2
MACULAR
Nasal step program – additional 12 locations upto 50 deg nasal
peripheral 60 and 60-4 prog
Estermann test – for binocular 120 deg field

37. MACULA PROGRAM :16 locations
within the central 5° with 2° spacing.
Each location is tested three times

38. STRATEGIES
SUPRATHRESHOLD – screening
Fixed suprathreshold
contour suprathreshold
3 zone suprathreshold

39. FULL THRESHOLD
BRACKETING STRATEGY( staircase)
– GOLD STANDARD
FASTPAC
Estimation of SHORT TERM FLUCTATIONS at 10 prefixed points

40. SWEDISH INTERACTIVE TESTING ALGORITHM (SITA)
SITA STANDARD ( Bracketing strategy based)
SITA FAST ( FASTPAC based)
Analyzes patients response and responds accordingly
Decreases overall no of stimuli presented, hence test
duration
Paces the test according to patients speed
Doesn‟t estimate Short term Fluctuations

41. • Selection of adequate test
• Proper environment
• Comfortable sitting position
• Adequate size of pupil >3mm
• Adequate Near correction
• Proper explanation – running of demonstration
• Reassurance – not all points will be seen
- test can be paused by keeping the response
button pressed

43. Patient data
• Name, DOB, eye
• Vision, refraction,
• Pupil diameter
Test data
• Date and time
• Program and strategy
• Background
illumination
• Test
size, color, duration, i
nterval
ZONE 1 : REPRODUCIBILITY

44. ZONE 2 : RELIABILITY
• Fixation monitor
• Fixation target – central, small
diamond, large diamond, bottom LED
• Test duration
• Reliability indices
Fixation losses ( Heijl Krakau) <20 %
Gaze tracking
False positives < 33%
(trigger happy)
False negatives < 33 %
Foveal threshold

46. ZONE 3 : GREY SCALE
• Based on actual threshold values at each location
• General identification
• Patient information

47. ZONE 4 :TOTAL DEVIATION PLOT
• Numerical plot – indicates by how
much decibels is each point depressed
compared to mean value in normal
population of similar age
• Probability plot- grey scale indicates
the probability of occurrence of the
deviation in normal population
Generalized depression due to media
opacities, refractive error, miosis may
hamper appearance of a pattern

48. ZONE 5 : PATTERN DEVIATION
PLOT
• Numerical - calculated by adjustment for
generalized depression or elevation of
visual field
• Thus brings out pattern
• Probability plot
• Significance - ANDERSON‟S CRITERIA

49. ZONE 6 : GLOBAL INDICES
single numbers to denote whole field
• MEAN DEVIATION : average loss of sensitivity from
normal age matched population along with probability
calculated from total deviation plot
• PATTERN STANDARD DEVIATION : range over which
change of sensitivity at all the points has occurred, along
with probability
compensates for effect of generalized depression or
elevation of field on mean deviation value
local defects affect PSD > MD
• SHORT TERM FLUCTUATIONS
• CORRECTED PATTERN STANDARD DEVIATION

50. ZONE 7 : GLAUCOMA HEMIFIELD TEST
• PLAIN ENGLISH LANGUAGE MESSAGE
• Comparison of 5 clusters of points in
superior hemifield with mirror images in
inferior hemifield

51. OUTSIDE NORMAL LIMITS
all cluster pairs differ @ p < 1% OR
1 cluster pair differs @ p < 0.5%
BORDERLINE
hemifields differ @ p < 3%
GENERAL REDUCTION OF SENSITIVITY
overall field depressed @ p < 0.5%
ABNORMAL HIGH SENSITIVITY
overall field elevated( best 15 % points) @ p < 0.5 %
WITHIN NORMAL LIMITS

52. ANDERSON and PATELLA CRITERIA
• 3 or more congrous „non edge points‟ in typical arcuate area
on 30-2 program
depressed @ p< 5 % with at least one point @ p<1 %
•PSD / CPSD @ p< 5%
•GHT – outside normal limits
 Must be demonstrated on 2 field tests

53. CLINICAL CORRELATION : MUST
DISC and NERVE FIBRE LAYER

54. OVERVIEW

55. CHANGE ANALYSIS

56. GLAUCOMA PROGRESSION ANALYSIS

57. ARTEFACTS
• OBSTRUCTION
RIM ARTEFACTS
PTOSIS
MEDIA OPACITIES
ANGIOSCOTOMA
• MIOSIS
• REFRACTION ARTEFACTS
• High power plus and minus lenses

62. NEWER METHODS

63. SHORT WAVELENGTH AUTOMATED PERIMETERY
“BLUE ON YELLOW”
detects glaucomatous defects 3-5 years earlier than SAP
high fluctuation rates

64. FREQUENCY DOUBLING
PERIMETRY
Based on frequency doubling
illusion
Test stimulus – series of white
and black bands flickering at
25 Hz ( low spatial frequency
& high temporal frequncy)
Detects damage to
Magnocellular Ganglion cells
C – 20  17 points – screening
N – 30  19 points – diagnosis
n management

65. RANDOM DOT MOTION PERIMETRY
Patient has to tell direction in which dots are moving
HIGH PASS RESOLUTION PERIMETRY
Test resolution and not mere threshold detection

66. THANK YOU