Samay shah Trupti parmar

1. -Samay Shah
-Trupti Parmar
3nd year B.OPTOM
BMCO , Surat

2. 1. Introduction of Visual Field
2. Hill of vision
3. Method of studying visual fields
4. History of perimetry
5. Indications of perimetry
6. Terminologies
7. How to perform perimetry test
8. Perimetry interpretation
9. Advance techniques for visual field measurement

3. Introduction of perimetry
 Perimetry – A standard test in ophthalmology and
optometry to assess a patient’s visual field.
• The devices used to perform this evaluation are called
perimeters.
• Perimetry is performed for several reasons;
 1)detection of pathologies
 2) evaluation of disease status
 3) follow-up of pathologies over time to determine
progression or disease stability
 4) determination of efficacy of treatment
 5) visual ability testing.

4. •Perimetry is most commonly used to diagnose glaucoma, but it is also often
used to assess visual loss resulting from retinal diseases, as well as optic nerve,
chiasmal or post-chiasmal damage due to trauma, stroke, compression and
tumors.
•Perimetry is used regularly for visual ability testing. Its most common use is
to test a person’s visual ability to drive.

5. Introduction of visual field
 The visual field of a person is defined as the area in which a
person can see at a given moment relative to the direction
of fixation, without head or eye movement.
 The entire expanse of space visible at a given instant
without moving the eyes.
 The monocular visual field consist of ….
superiorly : 50 deg , nasally : 60 deg , inferiorly : 70 deg &
temporally : 90 deg

7. THE HILL OF VISION – A VISULZATION OF VISUAL FUNCTON
 Its a 3D representation of the retinal light sensitivity.
 Traquair reflects the visual field in the light-adapted
or photoptic visual field.
 The highest concentration of cones is in the fovea ,
most of these cones project to their own ganglion cell.
 The contour of the island
of vision changes greatly
in the mesopic(twlight)

8. Con…
and scotoptic (dark-adapted) states .
 In the dark-adapted island of vision , the contour is
flatter than in the light-adapted state .

9. Methods of measuring the visual field
 The visual field can be tested in a few different ways ,
including the confrontation visual field exams ,
tangent screen test & perimetry exam . Your Dr. may
perform one or a combination of these testes to
examine your visual field .
 Using the result of these tests , your Dr will be able to
determine if you are having trouble seeing in certain
areas of your visual field , as well as possible causes for
these difficulties .

10. 1. Tangent Screen Exam
 Also known as begrrum’s screen or campimetry
 The tangent screen exam (Goldmann field exam ) can
be conducted in your eye doctor’s office . Patient will
be seated about 3 feet away from a screen . This
screen will have a target in the center for you to focus
on throughout the test .

11. Con….
 The computer will generate image on different areas of
the screen .Without moving your eyes , you will tell
your Dr. when you’re able to see objects in your side
vision . Your Dr. will be able to use the information
collected to from a map of your visual field . This will
help them determine if there are certain areas in your
visual field that you are not able to see .
 The location of these areas can help your Dr. diagnose
the cause of the visual field problems .

13. 2. Perimetry
 Perimetry is the systemic measurement of visual field
function .
 Perimetry will detect loss of peripheral vision &
provide a map of that loss which will be helpful in
diagnosing the cause of the loss .
 It is the measurement of HILL OF VISION in terms of
establishing the patient’s differential light sensitivity
across the visual field.

14. When is perimetry called for?
 Perimetry is essential in glaucoma management .
 It also is frequently useful in diagnosing & managing
neurological diseases and it has a role in the
diagnosing & managing of some retinal diseases .

15. HISTORY
 1970 – The original octopus perimeter was first
introduced . Bucz , of its room size & high expensive
nature it become unpopular .
 1980-, BJERRUM developed tangent screen
 1982 – Humphrey field analyzer was first displayed at
American Academy of Ophthalmology .
 1983 – Michal Patella showed its first clinical trail .
 1984 – started production & become very popular bucz
, of its small size & affordable price .

16. Indications of Perimetry
 Detection of glaucoma , progression
 Chorioretinal lesions
 Optic disc & optic nerve lesions
 Neuro-ophthelmological diseases
 Abnormal color vision
 Reduction in visual acuity that can’t be improved with a
pinhole , stenopaic slit or refractive correction

17. Types of Perimetry
 According to the principal :
1. Kinetic
2. Static
 Clinically
1. Automated static perimetry
2. Manual kinetic & static perimetry using a (Goldmann type bowl
perimeter )
3. Potable perimetry

18. Kinetic perimetry
• Outer visual field is determined by moving objects from the non-seeing area
to the center .
• Uses a moving object of a fixed size & intensity .
• It is manual
 Advantages :
• Allows large areas to be traversed in a fairly short period.
• Less expensive & durable .
• Perimetrist is constantly communing with the patient so it is more comfortable .
 Disadvantage :
• Reproducibility & reliability is not constant in the manual kinetic perimetry .
• Early changes can overlooked
 Eg : Goldmann perimeter

19. WHAT IT IS BEST AT DETECTING:-
 Small changes in spatial extent of a defect
 Peripheral changes
 Remaining vision in advanced diseases
USES:-
 Neuro-ophthalmological conditions{vision loss or disturbance
,double vision unequal pupils etc…}
 Peripheral retina diseases
 Low vision
 Patient with cognitive impairment

21. Static perimetry
•The outer boundary of island of vision determined by measuring the retinal
sensitivity at each point .
•The test location is fixed while the intensity of the test object of known size
is varied.
•It’s automated
Advantage:
•Reliability and reproducibility
• Clinical gold standard
•High precision sensitivity thresholds
•Fully automated
Disadvantage:
•Manual static perimetry is tedious
Eg: Octopus or the Humphrey Field Analyzer

22. WHAT IT IS BEST AT DETECTING:-
•Small changes in sensitivity thresholds
•Changes in the central area
USES:-
•Glaucoma
•Macular diseases
•Visual ability testing

24. Manual perimetry

25. Portable perimetry
 palsamScan VF2000 is potable , battery operated , virtual based visual field analyzer
developed to be able to measure the pt’s visual field defect accurately and reliably .
 The VF2000 is composed of 3 major sections that are connected to each other
wirelessly & there are no wires to deal with when using this system .
 The 3 major components are:
1. The test goggles that are worn by the patients
2. The controller device that is used by the health care provider to set the parameters
and to monitor the progression of the test
3 . The clicker that the patient will use to notify the system that a stimulus has been
detected .

26. Why portable is best ?
No Need For Dedicated dark room
No need to patch the fellow eye
No need for trial lenses on majority of patients
Measure any patient anywhere
Proven accuracy
Increased your office revenue
Disposable and protective facemasks
Can be used for pediatric patients
Disadvantage :
Don’t provide enough clinical data to manage glaucoma patient

28. Few Terminologies
Threshold :
-Differential light sensitivity at which a stimulus of a given size and duration
of presentation is seen 50%
-The threshold is the physiological capacity to detect a stimulus at a given location
under specific condition.
Suprathreshold :
-95% of the projected times
-stimulus- made suprathreshold – increasing size or duration
Infrathreshold :
-Low intensity stimulus – 5%
Isopter :
a line on a visual field representation – connecting points the same
threshold .

29. -Depression:
a decrease in retinal sensitivity
-Scotoma :
an area of decrease retinal sensitivity within the visual field
surrounded by an area of greater sensitivity .
Decibel (dB):
-Its value depends on the max. illumination of the perimeter
40 dB = 1 asb unit
0 dB = 10,000 asb unit
-The conversion from asb to dB is log & not a simple
multiplication factor .
-Good retinal sensitivity = 40 dB
-Poor retinal sensitivity = 0dB
-Dimmest light = 1 asb
-Brightest light = 10,000 asb

30. 30-2 central threshold test pattern
 no. of test points: 76
 Dist. b/t each two points : 6 deg
 Indications : suspect cases of glaucoma

31. 24-2 central threshold test pattern
 No. of test points : 54
 Dist. b/t each two points : 6 deg
 Indications : establish cases of glaucoma

32. 10-2 Central threshold test pattern
 No. of test points : 68
 Point density : 2 deg
 Indication : advance case of glaucoma

33. Macular program
 No. of test pints : 16
 Point density : 2 deg
 Indications : advance case of
glaucoma

34. How to perform perimetry test
 Perimetry should be performed in a Distraction-free
environment, to enable the patient to concentrate on
the perimetric test .The room should be quiet, with no
activity distracting the patient, and should be at a
comfortable room temperature.
 The room should be kept clean and free of dust and
particles.
 The perimeter is automatically calibrated each time it
is turned on.

35. A perimeter should be set up in a distraction-free, dimly-lit
environment.

36. STEP-BY-STEP PATIENT INSTRUCTIONS
1 Perimetry tests your central and peripheral vision.
2 Be relatively still once positioned.
3 Always look straight ahead at the fixation target. Do not
look around the bowl for stimuli.
4 Press the response button whenever you see the stimulus.
 a. The stimulus is a flash of light.
 b. Only one stimulus is presented at a time.
 c. The stimulus might appear anywhere.
 d. Some stimuli are very bright, some are very dim,
 and sometimes no stimulus is presented.
 e. You are not expected to see all stimuli.
 f. Do not worry about making mistakes.

37. Con…..
5. Blink regularly to avoid discomfort.
a. Don’t worry about missing a point, the device does not
measure while you blink.
6. If you feel uncomfortable or are getting tired
a. Close your eye for a moment, the test will
automatically stop.
b. The test will resume once you open your eye.
7. If you have a question
a. Keep the response button pressed; this will pause the
test.

38. CORRECT PATIENT POSITION
 The patient should be seated in a comfortable position that
can be easily maintained throughout the test.
 A height-adjustable chair with a backrest and, if available,
armrests should therefore be used.

39. CORRECT EYE PATCH POSITION:
 Before fully positioning the patient, the eye not being tested should be
covered with an eye patch that allows the patient to blink freely.

40. PLACING AN ADEQUATE TRIAL LENS
 The trial lens calculator is helpful in determining the
adequate spherical and cylindrical trial lenses, based on
the patient’s current refraction and age.
 Trial lenses with a narrow metal rim should be used, to
prevent the rim of the trial lens from blocking the
patient’s field of view.
 We use full aperture trial
lenses.

41. CORRECT EYE POSITION
 Once the patient is correctly positioned in the device, it is important
to ensure that the eye is also correctly positioned.
 The left-hand panel shows an eye in the video monitor that is
correctly positioned ,with the cross-hair target located within the
boundaries of the pupil.
 The right-hand panel shows an eye that is incorrectly positioned, with
the cross-hair target located outside the boundaries of the pupil.

42. SELECTING A TEST PATTERN
INDICATION RECOMMENDATION COMMON
ALTERNATIVES
GLAUCOMA/CENTRAL FIELD G (Glaucoma) 32, 30-2, 24-2
MACULA M (Macula) 10-2
FULL FIELD (NEURO, RETINA) 07 Kinetic
FOVEA F (Fovea)
BLIND SPOT B (Blind spot) Kinetic
LOW VISION M, G, 07 depending on
pathology
Kinetic
SCREENING FOR ABNORMAL
VISION
Screening 28
DRIVING ET (Esterman) FG (Führerscheingutachten),
Kinetic
BLEPHAROPTOSIS BT (Blepharoptosis) Kinetic
BLINDNESS BLINDNESS

43. 1.)TEST PATTERNS FOR GLAUCOMA:-
•Glaucoma is a disease resulting in the degeneration of
retinal nerve fiber bundles in the eye.
•Typical defect patterns follow the distribution of the retinal nerve fiber bundles
and there is a clear separation along the superior and inferior hemifields at the
horizontal meridian.
•Since glaucomatous visual field defects typically occur within the central visual
field, the best trade-off between test duration and accuracy is achieved by using
a central 30° test pattern.
•In very advanced glaucoma, the visual field and therefore, it is common to
switch to a 10° macular test pattern in advanced glaucoma
.

44. . 32/30-2 AND 24-2 PATTERNS
•The 32, 30-2 and 24-2 patterns are similar to the G pattern in that they
cover the central visual field and respect the vertical and horizontal
meridians. In contrast however, they are not optimized for specific
pathologies.
•Instead, all test locations are equidistant from each other and separated by
6°.

45. 2.)TEST PATTERNS FOR NEUROLOGICAL VISUAL FIELD LOSS
•Neurological conditions lead to a large variety of typical visual field defect
patterns which are very specific, depending on the location at which the
visual pathways are affected
•Lesions of the optic disc and optic nerve lead to unilateral (i.e., only
affecting one eye) visual field defects. Common optic nerve and nerve head
diseases include disc edema, optic neuropathies, optic neuritis,
compressive lesions such as those caused by idiopathic intracranial
hypertension, and a number of congenital abnormalities, such as optic
nerve head drusen.
•Chiasmal lesions resulting from diseases such as pituitary adenomas and
related lesions typically result in bitemporal (i.e., left and right eye defects
are mirrored) hemianopias, which progress from the superior to the
inferior hemifield, but always respect the vertical midline.

47. 3)TEST PATTERNS FOR THE MACULA:
M PATTERN
The M pattern is most commonly used for the testing of drug-induced
maculopathies, to follow up advanced-stage glaucoma patients, and for visual
function testing in patients with AMD or other macular dysfunction.

48. 4)TEST PATTERNS FOR VISUAL ABILITY TO DRIVE:-
•Safe driving requires a large horizontal field of view, to be able to notice other
cars coming from the side, and a fairly intact central field of view, to be able to
notice obstacles ahead.
•As driving is performed with both eyes open, the binocular field of view is
relevant for safe driving.

50. BT PATTERN FOR BLEPHAROPTOSIS(BT test):-
•The BT pattern is designed speciically for blepharoptosis testing and
covers the area of the lid lines in the superior Some legislations also
accept driving ability tests performed with kinetic perimetry.
•As there is no vision underneath the lid
line, qualitative testing (seen, not seen) is sufficient.
The BT pattern for blepharoptosis testing covers the area of the potential
lid line.

51. Interpretation of perimetry

52. Zones of field analysis
 1. Independent of normative data:-
zone 1 : Patients data/ test data
zone 2: Reliability indices/ foveal threshold
zone 3: Raw data
zone 4: Gray scale
 2. Dependant of normative data:-
Zone 5 : Total deviation numerical plot
zone 6 : Total deviation probability plot
zone 7 : Pattern deviation numerical plot
Zone 8 : Pattern deviation probability plot
Zone 9 : Global indices
Zone 10 : Glaucoma hemifield test
Gaze tracker(Eye tracking)

53. Zone1: Patients data/ test data
Fixation monitor : Blind spot
Color of stimulus : White
Background illumination : 31.5 asb
1.Age of the patient:
it is very important to enter the age of patient accuracy.
2. Size of the pupil :
Normally the size of the pupil should be b/t 3-4 mm
3. Refractive error :
The pt’s near vision refractive error must be properly corrected.
otherwise the visual field will show generalized depresstion.
4.Stimulus size
The standard size of the stimulus is size III for all routine tests & size V for
advance glaucoma
CONSTANT

55. Zone 2 : Reliability indices/ foveal threshold
 Reliability indices
fixation loss : >20% is unreliable
false positive : >33% is unreliable
false negative : > 33% is unreliable

56. Zone 3: Raw data
 Exact retinal sensitivity in dB units of the selected points
 Only numerical value of the retinal sensitivity is displayed
in the raw data & dB units are omitted.
 in the raw data ,
‘0’ indicates Absolute Scotoma(no response to
the highest light sensitivity i.e. 10000 asb unit )
‘40’ indicates highest retinal sensitivity i.e. 1 asb
unit

57. Zone 4: Gray scale
 Based on actual threshold value at each locating
 Areas of high sensitivity are denoted by lighter shades
& areas of low sensitivity are denoted by darker shades.
 Quickly identification overall depression
 Not use for diagnose
 Good for pt’s education

58. Zone 5 : Total deviation numerical plot
 Words O indicates retinal sensitivity is equal to mean
value of same age group
 Value without sign (positive) the measured retinal
sensitivity is better than mean normal values of the
same age group
 Numerical value with negative sign indicates the
measured retinal sensitivity is worse than the
mean normal values of the same age group

59. Normal retinal
sensitivity
Patient's retinal
sensitivity
Difference

60. zone 6 : Total deviation probability plot
Aim to be field chart is show that the field loss in scotomatous form
Probability value (P value ) : Indicates the significance of the defects
lower the p value the grater is its clinical significance
Clinical significance : if there are abnormal points in total deviation
plot that persist in pattern
TDNP TDPP
P value

61. Zone 7: pattern deviation numerical plot
 It is a modified from of TDNP to bring out scotomas
 7th best retinal sensitivity of TDNP is converted to zero
 Addition of the threshold value that converts the 7th
best retinal sensitivity of TDNP to all points in TDNP
 The pattern deviation numerical plot is also the basis
for glaucoma hemifield test analysis
 The TDNP is converted to PDNP without changing the
contour of hill of vision

62. TDNP
PDNP

63. Zone 8 : pattern deviation probability plot
 It is similar to formation of TDPP from TDNP
 It bring out deep scotomas in a generalized depression
 The main deference b/t TDPP & PDPP is that it
differentiate b/t actual field defects and loss of
sensitivity due to media opacities such as cataract,
corneal haze etc….

64. PDNP
PDPP

65. ZONE 9: Global indices
 These are develop to express the height of hill of vison
and contour of hill of vision
 It include : 1. mean deviation (MD)
2. Short term fluctuation (SF)
3. Corrected pattern standard deviation (CPSD)
4. Pattern standard deviation (PSD)

66.  1. MEAN DEVITION:
- Indicates overall depression or elevation
- Positive indicates better than normal field and vice-versa
- Negative value indicates that the pt’s overall sensitivity is
worse than the average normal
- Expressed in dB units with p value

67. 2. Short term fluctuation
-It measures the variation at each point on repeated
thresholding in the same test
-Value is almost always less than 3 dB
-Use to correct PSD to produce CPSD
-Indicates reliability and pathology
3. Corrected pattern standard deviation (CPSD)
- Intra testing variability (SF) is removed from PSD for produce
CPSD
-CPSD is not calculated if SF is not estimated during the test

68. 4 Pattern standard deviation :-
-Derived from total deviation plot
-Tells us how different each point is from one and other
- Actual irregularity in the field

69. Zone:10 Glaucoma hemifield test
 5 sectors in the upper field are compared to 5 mirror images in the
lower
 Five sectors are:
1. OUTSIDE NORMAL LIMITE
If, difference found in 1% population
2. BORDERLINE
If difference found in up to 3% population
3. ABNORMALLY LOW SENSITIVE
Best sensitive part is seen in less than 5% of
the population
4. ABNORMALLY HIGH SENSITIVE
Best sensitive part seen is more than that found in
99 – 5% population

70.  Gaze tracker :
 Heiji-Kraku method of fixation monitoring – it provides
index of quality of patient fixation during examination by
periodically exposing stimuli in blind spot
 Infra red gaze monitors
 Upward spikes indicates that the patient has lost fixation
 Short reaching the top line indicate 5 degree off fixation
 Long spikes indicate pt blink at the time of fixation check

71. Advance techniques for examine visual field
 SWAP [Short Wave Automated Perimetry]
 FDP[Frequency Doubling Perimetry]
 HPRP[High Pass Resolution Perimetry]
 Flicker Perimetry
 Multifocal Electroretinaography
 ACCUMP[Multifocal Visual Evoked Potential]
 Motion Perimetry

72. Some different reports
Early peracenral Scotoma

73. Moderate inferior acute Scotoma

74. Moderate superior acute scotoma

75. Ptosis

76. Cataract

78. ? ANY DOUTS ?

79. VISUAL FIELDS EXAMINATION AND
INTERPRETATION – THOMAS J. WALSH
A visual field evaluation with automated devices by GR
Readdy
Ophthalmology - Yanoff and Duker