Automated perimetry is an important diagnostic test used to map the visual field and detect progression of diseases like glaucoma. There are two main types - kinetic perimetry where a stimulus is moved and static perimetry where stimulus intensity is varied at fixed points. Static perimetry provides a more accurate 3D representation of the visual field. Different testing strategies like full threshold, threshold, and suprathreshold are used to detect visual field defects. Automated perimetry generates various indices to analyze results and detect progression of defects over time through comparison to baseline tests. Care must be taken to avoid sources of error and false indications of change.

1. Automated Perimetry
Dr.Vikram.S.Nakhate
Dr.Vijay.Shetty

2.  Automated way of mapping the visual field
 Important diagnostic test in glaucoma
 Diagnosing and monitoring progression of other
disease

3.  Traquair described it as a field of vision in a sea of
darkness
 It has a shape of a hill
 Peak representing fovea
 2 slopes representing nasal and temporal field of
vision

6. Kinetic perimetry
 Stimuli is moved from a non seeeing area to a seeing
area along a set meridian
 Aim is to find points in the visual field of equal retinal
sensitivity
 Lister perimetry
 Campimetry
 Goldman perimetry

7. Static perimetry
 Intensity of the stimuli at the same pre determined
spot is varied
 Find out threshold at those locations
 More accurate than kinetic perimetry
 Gives a 3D picture of the hill of vision
 Picks up field defects more accurately

8.  Apostlib is an absolute measure of luminance and is
equal to 0.3183 candela m2 or 0.1 mililambert
 Decibel is a measure of sensitivity of retina
 Inversely proportional
 It is a relative measure varies from machine to
machine

9. Testing strategy
 Full threshold
 Threshold
 Suprathreshold

10. Full threshold strategy
 Staircase method (4-2 bracketing strategy)
 Used to detect threshold

11. 4-2 bracketing
 Intensity of stimulus is decreased in 4-db step till
stimulus is no longer seen
 Increasing the stimulus in 2-db step till stimulus is
seen again

12. Threshold perimetry
 Threshold found at predetermined points
 Time consuming process

13. Suprathreshold perimetry
 Intensity of stimulus shown at a spot much higher
than threshold at that spot
 Mainly for screening
 Picks up gross visual defects

14. Newer threshold strategy
 Fastpac:
 Decreases the test time by 40%
 3-db increment instead of 4-db
 Threshold crossed only once

15.  Sita standard:
 Takes half time than full threshold method
 Sita fast:
 Takes half time than fast pac threshold method

16. 30-2
 Number of test points:76
 Density :6 degree
 Only 3 degree bare area is left surrounding the
fixation spot

17. 24-2
 Number of test points:54
 Density: 6 degree
 Only 3 degree bare area is left surrounding the
fixation spot

18. 10-2 central threshold test
 Number of test points: 68
 Density: 2 degree
 Only 1 degree bare area is left surrounding the fixation
spot

19. Macular programme
 Number of test points: 16
 Density: 2 degree
 Only 1 degree bare area is left surrounding the fixation
spot

20. Reliabilty indices
 Fixation losses:
 Indicates steadiness of gaze
 Presenting stimuli at blind spot
 loss.>20% is unreliable

21.  False positives
 Trigger happy patients
 Responds to an audible stimuli when no target is
presented
 >33% is unrelible

23.  False negative:
 Fails to respond to a suprathreshold stimuli
 Indicates fatigue,inattentiveness
 >33% is unreliable

26. Zone 1
 Colour of the stimulus
 Background illumination: 31.5 asb
 Stimulus size: III
 Testing strategy

28. Zone 3

29. Zone 4 total deviation
 Depicts difference between patients threshold fom
that of age matched normals
 Reveals generalised depression
 Cannot confirm scotoma

30. Zone 5 pattern deviation
 Reveals focal defects after adjusting for overall
depression
 Confirms scotoma

37. Global indices
 Mean deviation:
 Indicates overall deviation of the visual field from
normal
 Positive number indicates an elevated field
 Negative number indicates a depressed field
 Cannot confirm scotoma

38. Psd
 Derived from total deviation
 Indicates the degree to which the numbers differ from
each other
 Highlights pot-holes in hill of vision
 Calls attention for scotoma

39. Short term fluctuation
 Measure of intra-test variability
 Threshold at 10 pre selected points is tested
 Difference between 1 & 2 measurement noted

40.  Cpsd is psd corrected for sf
 If sf is due to unreliability
 Then cpsd is better
 If sf is due to pathology
 Then psd is better

42. GHT
 5 set of points above horizontal meridian
 Compared to mirror image below horizontal meridian

44. Zone 8
 Numerical display:
 Gives the threshold for all points checked
 Value in () indicates that the point has been tested
twice

45.  Never rely on first report
 Always correlate clinically
 Correct any significant refractive error before
proceeding

46. Sources of error
 Miosis:
decreases the threshold sensitivity in peripheral field
Increases the variability in central field
 Uncorrected refractive errors:
Threshold sensitivity appears less
 Hyperopic patient with contact lens:
Defect gets magnified & vice versa

47.  Spectacles can cause rim scotomas
 Ptosis :
Suppression of superior visual field

48. 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

49. False progression
 Learning curve
 Long term fluctuation
 Pupil size

50.  Pupil: 1 mm

51.  Pupil: 2.5 mm

52. Andersons criteria
 1. pattern deviation plot:
 3 non-edge points with p<5%
 One point with p<1%
 Cluster in arcuate area
 2.cpsd
 Abnormal with p<5% on 2 consecutive occasion
 3.abnormal GHT

53. CATARACT

54. GLAUCOMA

55. CATARACT & GLAUCOMA

56. Detecting progression
 Overview printout
 Glaucoma change probability analysis

57. Overview print out
 Sequential series of field of same patient over a period
of time
 Displays gray scales,total &pattern deviation
 Statistical analysis is however not provided

58.  This patient developed cataract,which was extracted
later
 Pattern deviation plot remained clear

60. Glaucoma progression

61. Glaucoma change probability
analysis
 Compares rate of change in patients visual field,with
that of stable glaucoma patient
 Clear triangle represents improvements
 Solid ones shows points of deterioration
 Progression represented by a cluster of black triangles
in same area increasing in size with time

64.  2 or more points deteriorate on 2 consecutive test

65.  3 or more points deteriorate on 3 consecutive test

66. Advanced field defects
 Why pattern deviation plot not showing defect

67.  Not enough points with sensitivity to produce pattern
deviation plot

68. Follow up with 10-2
 Enough sensitive points to produce pattern deviation

69.  Advanced defect f/u with a size V target(64mm2)

70.  Macular programme in advanced defects

71. Size V target:macular split
 Macular split (0 db) next to fovea may indicate wipe
out

72.  Thank you