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Methods Block 12 > Foundations Of Visual Field Interpretation > Flashcards

Foundations Of Visual Field Interpretation Flashcards

1
Q

Threshold determination

A 
Age matches normal data are used to compare patients data 
-normal range determined by: 
—Sensitivity of each retinal point 
—upper 95% as normal 
—lower 5% as abnormal
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2
Q

When is suprathreshold used for

A

Disability and driving

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3
Q

The lower the decibels

A

The brighter the stimulus

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4
Q

The part of the visual field that corresponds to the fovea

A

Fixation

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5
Q

Localized defects/depressions surrounded by normal vision

A

Scotoma

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6
Q

Defect that persists when the maximum stimulus is used, e.g. blind spot

A

Absolute scotoma

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7
Q

Defect that is present to weaker stimulus but disappears with brighter stimulus

A

Relative scotoma

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8
Q

Reduction both peripheral and centrally

A

Generalized depression

-cataract

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9
Q

Peripheral depression

A

RP

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10
Q

Which VF has the least amount of points tested

A

24-2

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11
Q

What is 10-2 used for

A

Extreme glaucoma

Plauqeunil

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12
Q

60 points 2 degrees apart

A

10-2

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13
Q

54 points 6 degrees apart

A

24-2

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14
Q

74 points

A

30-2

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15
Q

What are the reliability parameters

A

Fixation loses
False positives
False negative

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16
Q

If the VF is not normal…

A
  • what was the fixation loss
  • what was the false positive and false negative %
  • were they properly refracted
  • do they have a ptosis/heavy
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17
Q

What is the most reliable relaibiltoy parameters

A

False positive

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18
Q

Trigger happy patients, responses to stimuli when no target is present

A

False positive

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19
Q

What si considered unreliable FP

A

> 33%

-if the FP exceeds 15% the field is considered unreliable and should be re run

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20
Q

Failed to response to suprathreshold stimuli, indicates fatigue, inattentivenss

A

FN

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21
Q

Clover leaf pattern

A

FN

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22
Q

What is considered unreliable with FN

A

> 33%

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23
Q

Fixation loses

A

Monitored by blind spot and gaze tracking

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24
Q

If the FL rate exceeds ____ it is flagged

A

20%

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25
Q

Threshold sensitivities measured at each test point, indicated in decibels

A

Numeric grid

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26
Q

___ dB indicates the max brightness target available for that test

A

0

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27
Q

Raw data

A

Numeric grid

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28
Q

Where should numbers be the greates in the numeric gird

A

In the center, less in the periphery

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29
Q

If there is <0 on numeric grid

A

Does not mean totally blind int hat spot but that the patient could not see the largest and brightest target available for that test

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30
Q

Provides an approximate picture of the field, good for patient education

A

Gray scale

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31
Q

Appears as numbers and graphics in the central left area of the printout, represents the difference between the measures threshold of each individual tests location and the age corrected normal vale for that location

A

Total deviation plot (dB); upper plot

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32
Q

Negative values for the total deviation plot; upper plot

A

Indicate sensitivities which are below the median age-corrected sensitivity

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33
Q

Positive values in the goal devation plot; upper plot

A

Indicate sensitivities which are above the median age corrected sensitivity

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34
Q

Graphics display plots the signicance of deviations found in the upper plot, using a small dot for a point within the range of 95% of the normal values or with a shaded box. See p value

A

Total deviation plot (dB); lower plot

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35
Q

Indicates ALL test locations that are outside a normal range

A

Total deviation plot

36
Q

Most common reasons for overall reduction or generalized depression

A

Cataracts
Incorrect trial lenses
Poor test taker

37
Q

Takes the total deviation plot and adjusts it upwards to downwards to screen out generalized depression, highlights only significant localized VF loss

A

Pattern deviation plot

38
Q

Symbols for pattern deviation plot

A

Uses the same symbols as the total deviation plot to show points which are significantly worse than normal P value

39
Q

Single most uself analysis on an SFA printout

A

Pattern deviation plot

40
Q

Highlights subtle, but significant localized variations that might otherwise be masked, early defects show up sooner on probability map than on gray scale plot

A

Pattern deviation plot

41
Q

It total deviation plot and pattern deviation are about the same

A

There is little to no generalized loss

42
Q

If abnormal TD plot and normal PD plot

A

Cataract, incorrect Rx

43
Q

If normal TD plot and abnormal PD plot

A

Trigger happy

44
Q

Significance of deviations from Normal in the probability plots (P value)

A

Indicated in the total deviation probability plot (P value)

45
Q

A 2% symbol indicates that fewer than 2% of normal patients have a sensitivity

A

That low or lower

46
Q

Found on the lower right hand corner of the printout, single number representations of the VF, MD, PSD

A

Global indices

47
Q

Shows how much (on average) the whole field departs from normal

A

Mean deviation

48
Q

(+) MD

A

Better than average

49
Q

(-) MD

A

Less than average

50
Q

Abnormal MD

A

P<0.5%

-less than 0.5% of the population has a mean deviation larger than the value found on the test

51
Q

Height of the hil of vision compared to age matched normals.

A

MD

52
Q

Measures the extent to which the threshold determinants at different locations differ from each other

A

Pattern standard deviation (PSD)

53
Q

This does not change with media (cataract)

A

Pattern standard deviation (PSD)

54
Q

The higher the PSD, the more

A

Irregular the pattern

-high PSD=more localized defects=more indicative of pathology

55
Q

Indicates the SHAPE of the hill of the vision

A

Pattern standard deviation

56
Q

If MD is abnormal and the PD is normal

A

Generalized defect

57
Q

Normal MD and abnormal PD

A

Small localized defect

58
Q

MD and PD both abnormal

A

Large defect with a localized components

59
Q

Interpretation and report

A
  • look at both eyes together
  • does the field make sense compared to other clinical findings
  • make sure data trustworthy
  • evaluate defect; any type of defect
  • repeatability of the defect
  • probable diagnosis
60
Q

Documentation of HVF

A
  • make statements referencing reliability
  • make statement regarding pattern, depth, and size of VF loss
  • make statements which correlates other exam findings with the VF
  • always remember to wrtie signature next to signatures
61
Q

Reasons for VF defect

A
  • glaucoma
  • retinal abnormalities
  • developmental optic disc anomalies
  • optic neuropathies
  • chiasmal lesions
  • homonymous hemianopia
  • functional vision loss
62
Q

Glaucomatous progression rate

A

Almost 10x faster than the normal rate of decline of visual function with age
-structural change usually precedes loss but not always

63
Q

Neuro causes of field loss

A

Stroke
Optic neuritis/neuropathy
Chiasmal tumors
Raised intracranial pressure

64
Q

Visual field defects obey

A

Anatomy

65
Q

Interpretation of the VF loss reveals the

A

Location

66
Q

Finding the location of the VF loss reveals the

A

Lesion

67
Q

Clues from exam

A

VA
Confrontational VF
RAPD
Color vision

68
Q

How does a droopy lid appear on a VF?

A

Looks like an accurate defect

69
Q

Ring defect on VF

A

Lens artifact

70
Q

Small pupil in VF

A

Lack of peripheral

71
Q

Ptosis

A

Superior field defects

72
Q

Called the true positive rate. Defined as the proportion of people with the disease who will have a positive result

A

Sensitivity

73
Q

A highly sensitive test is one that does what

A

Correctly identifies patients with a disease

74
Q

A test with 100% sensitivity will identify

A

All patients who have the disease

75
Q

If a person has a disease, how often will the test be positive (true positive rate)?

A

Sensitivity

76
Q

If the test is highly sensitive and the test result is negative you can be certain

A

That he don’t have disease

77
Q

A ______ helps rule out disease when the result is negative

A

Sensitivity

78
Q

TP/(TP+FN)

A

Sensitivity

79
Q

The specificity of a test (also called the TN rate) is the proportion of people without the disease who will have a negative result

A

Specificity

80
Q

Refers to how well a test identifies patients who do not have a disease

A

Specificity of a test

81
Q

A test that has 100% specificity will identify

A

100% of patients who do not have the daises

82
Q

If a person does not have the diasease, how often will the test be negative (TN. Rate)

A

Specificity

83
Q

If the test result for a highly specific test is positive you can be certain that

A

They actually have the disease

84
Q

TN/(TN + FP)

A

Specificity

85
Q

High sensitivity tests have low

A

Specificity
-they are good at catching actually cases of the disease but they also come with a fairly high rate of false positive (mammograms)

86
Q

Low sensitivity/high specificity

A

UTI

Methods Block 12 (4 decks)

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