Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Summer Final: Glaucoma > VF Testing > Flashcards

VF Testing Flashcards

1
Q

Testing strategies

A
  • automated perimeter
  • manual perimeters (tangent screen, Goldman bowl perimeter)
  • CVF
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

The systemic measurement of visual function

A

Perimetry

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The measurement of hill of vision in terms of establishing the patients differential light sensitivity across the VF

A

Perimetery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Threshold

A

Location at which detecting threshold is determined

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How are sensitivity and threshold related

A

Inversely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Standard Humphrey VF: kinetic or static?

A

Static

-present different targets, but they are not moving targets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Tangent screen: kinetic or static?

A

Kinetic

- physically moving the target

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

0dB sensitivity

A

Very low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Typically range of abnormal vision

A

0-30dB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Normal peripheral sensitivity range

A

20-40dB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Limit of fovea vision

A

40dB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Defined as that area of vision seen with open eyes

A

Visual field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Dimensions of the visual field defined

A

Defined relative to fixation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Basis of VF

A

Present of pR and corresponding visual pathways up to the periphery or retina away from point of fixation (fovea)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Importance of VF

A

Reflects topographic sensitivity of various foci on retina and corresponding visual apparatus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How should you look at VF

A

OD on the right and OS on the left so you can see differnt heminaopsia correctly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Status perimetry

A
  • computer presents stimuli in a random fashion
  • speed is also improved with random presentation
  • allows for storage of data
  • computer assisted stat analysis is available
  • most widely used intros meant is the Humphrey VF
  • testing methods and stat analysis vary among manufacturers
  • static auto perimetry measures retinal sensitivity at predetermined points throughout the VF
  • threshold values are determined to discover the shape of the hill of vision
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How does static perimetry measure threshold

A

Stimulus at a stationary position is presented by increasing or decreasing the luminance until just noticed by the patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

HFA-3

A
  • newest one
  • bowl/projection
  • optical system
  • central processor
  • patient interface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is special about the HFA-3

A

-liquid lens technology allows you to automatically load each pateitns refractive correction form the previous exam

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

SITA faster

A

About half the time of SITA standard and 70% of SITA fast with the same reproducibility as SITA fast
-may improve patient satisfaction with perimetric testing and reduce patient fatigue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What kind of add do you use for presbyopia in HFA-2

A

3.33

Working distance is 30cm not 40 so cannot use 2.50 as a max

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

HVF: bowl

A
  • aspherical surface where stimuli are projected
  • distance from the eye to the center of the bowl is 30cm
  • this value dictates the warranted corrective lens wchi should be used dudeitn testing
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Optical system in HVF

A

Provides stimuli of known brightness for a known amount of time in aprecise location against a background of known background

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

HVF background lumincation

A
  1. 5asb

- dimmer background allow a machine to Preston brighter stimulu to the visua lsystem with respect to background light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

HVF: stimulus size

A
  • utilizes the same target size as a Goldman perimeter: I, II, III, IV, V
  • all size III targets is most often used during testing, however size V stimulus is used on occasions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Diamter of the III size in HVF

A

2.26mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Stimulus intensity of HVF

A
  • 0.08asb (51db)-10,000 (0dB)
  • brightest target is equivalent to goldmann V4e
  • does not switch between target sizes (changes brightness of target only)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Stimulus duration of HVF

A
  • around 0.2s

- patient does not have time to see a stimulus in their periphery and look towards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Brightest setting on golamdnn

A

V4e

10,000asb

31
Q

Fixation monitoring in HVF

A

Includes examiner ability to view the patients eye, an electronic eye motion detector (gaze tracker) and blind spot monitoring

32
Q

Blind spot monitoring

A

Provides an index of the quality of fixation by presenting a stimuli in the blind spot-positive responses indicate poor fixation

33
Q

Gaze tracker

A
  • measure gaze direction with precision of approx one degree

- these tracking results are shown on the video screen and are printed at the bottom of the print out

34
Q

Calibration of HVF

A

-done automatically by the instrumentcalibration of background and target

35
Q

Room luminance and HVF

A

Should be dark without visual or auditory distractions

36
Q

Data entry of HVF

A
  • always enter the date, time, patients name, identification or chart number,and BD
  • can also add VA, pupil diameters, and refractive error
37
Q

HVF pateitn set up

A
  • always disinfect surfaces
  • one eye is occluded
  • chin holder adjusted until the pateitns virwing eye is centered in crosshairs on the screen
  • lens holder containing appropriate near spectacle ass is placed as close to the patients eye as possible without touching the lashes
38
Q

Considerations for HVF

A
  • anyone who is aphakic
  • anyone who is pseudophakic
  • anyone that has been dilated
39
Q

Is it better to be dilated or miotic for VF

A

Dilated is better, but dont want to be either really

40
Q

Trial lens placement for HVF

A
  • rimless trial frame
  • if Plano, put the lens holder down
  • ensure the trial lens is as close as possible to the patient without touching the patients lashes
  • if performing peripheral VF (outside the central 30), you must remove the trial lens
41
Q

Patients instructions for HVA3

A
  • instructions are extremely impiortnat
  • if not given properly, will affect test results
  • show the patient the button press and how to operate
  • patient should be shown the yellow fixation light in the center of he HVF and instructed to look at it throughout the entire test-must NOT look away
  • explain that while the fixate on the central light, the computer will flash small spots of light in their side vision
  • they are not to look at the side lights-keep looking straight ahead
  • press the button each time they believe they views light off to the side )even if they only thin they’ve seen it)
  • ok to blink when needed
42
Q

HVF during the test

A
  • watch for fixation losses
  • do not leave the room
  • reposition pateitn slightly if necessary during the test
  • perform test on other eye
  • always save and print results
43
Q

HVF: procedures

A
  • examination strategy
  • screening
  • standard algorithm (full threshold)
  • FASTPAC
  • SITA
44
Q

Screening HVF

A
  • single intensity
  • threshold related
  • three zone
45
Q

Standard algorithm (full trehshold )

A
  • full threshold
  • full threshold from prior data
  • fast threshold
46
Q

Screening on HVF

A
  • not quantitative
  • save time
  • reserved for new patients where the suspicions of a defect is low
  • if defects are found, examination using a threshold test hsould be performed and used to monitor disease
47
Q

Single intensity on HVF

A

One value of brightness is presented at all points being tests
-default is 24Db

48
Q

Threshold related: HVF screening

A

Makes the screening target threshold the same across the entire filed
-me Audrey a central threshold and a peripheral threshold and then creates a normal hill of vision from the two values

49
Q

Three zone: HVA

A

Takes threshold a step further
-if the suprakthreshold target is missed that spot is retested later with a maximum intensity target of 0DB (10,000 abs)

three zone results:

  • normal (Sade suprathershold)
  • relative defect (missed Supra, but Saw max)
  • abolsute defect )did not see max)
50
Q

Full threshold

A

Most time sounding, however most accurate and repdoruducle

  • threshold is detemeind for one primary point per quadrant. 9 degrees away from horizontal and vertical (30-2)
  • this is then used to determine starting point for the staircase at other locations thrghouout the fiel
  • these trehshlds then feed into the staircase onset of their neighbors
51
Q

Staircase of full threshold

A
  • consists of 4dB decrement in light intently until the patient fails to repsosne=1st reversal
  • then 2Db increments uintl the pateitns faisl to see the light again=2nd reversal. This level is the sensitivity printed
  • primary points habe threshold estimated twice
52
Q

If any threshold value deviated by >5dB from expected, then it

A

Brackets the thriesld once’s more

)parenthesis if more accurate than bracket)

53
Q

FASTPAC

A
  • alternative to full threshold
  • changes stimulus instensity by 3db and only crosses the threshold once
  • can reduce test trim by as much as 35% however, this comes at an expense to accuracy
  • less precise
54
Q

SITA

A
  • uses method of detecting threshold values for 4 ptimayt point in each quadrant
  • these are used to generate starting levels of neighboring points
  • the result is that threshold determination is reached in a shorter amount of time but with the same accuracy as a fullthreshold
  • monitor test point results and utilizes a complex stat technique which assigns a level of confidence for how close each point it to its final value
55
Q

SITA standard vs SITA fast

A
  • main difference is the level of confidence. Standard is more reproducibly
  • standard sets a higher level of certainty which requires more trials at a give point this its more accurate
  • SITA fast takes less time
56
Q

Which is good for glaucoma tracking

A

24-2 or 30-1

57
Q

Central 30

A

-76 test point locations that’s covers the central 30 degrees
Spaced 6 degrees apart

58
Q

Central 24

A
  • 54 test point locations
  • covers the central 24 degrees, except nasally where it extends 30 degrees
  • space locations 6 degrees apart
  • can pick up a nasal step in glaucoma where early glaucoma damage starts
  • still covers 30 degrees at the nasal margin
59
Q

Central 10

A

68 test point locations

Spaced 2 degrees apart (instead of 6)

60
Q

Version 1 HVF

A
  • spaces locations 6 degrees apart

- places testing locations on the horizontal and vertical meridians

61
Q

Version -2 of HVF

A
  • spaces locations 6 degrees apart
  • places testing locations flanking the horizontal and vertical meridians

Almost never use -1. -2 is the most used

62
Q

Periphal zone

A
  • mapping of the field between 30 and 60 degrees (30/60-1, 30/60-2, 60-4, current test on HFA3)
  • meant to supplement a central field exam when a more extensive dield defect is suspected
  • seldom used, such defects better evaluated with Goldman
63
Q

Full field

A
  • threshold strategies not available for full field programs
  • takes too long to acpcmplosh
  • divert to goldmann
64
Q

SWAP

A

Designed for early detection of glaucoma based on the theroty that glaucoma selectively damages door wavelgnth fibers first

  • also known as BY perimetry
  • 31.5asb background with a yellow background of 100-200
  • blue filter is placed int he stimulus projection pathway
  • sive V is used
  • stimulus duration of 0.2 seconds remain constant
65
Q

Indications of HVF

A
  • suspected VF defect
  • retinal disease (RP)
  • neuro ophthalmic disease
  • glaucoma
66
Q

Quantitivative tsting

A
  • purely quantitative
  • performed in order to quantify a suspected VF
  • performed in order to establish baseline fueled against which future fields may be compared
  • high sensitivity
67
Q

Advantages of VF

A
  • testing administration is more satnadardizable
  • minimizes test variability
  • improves reliability
68
Q

Disadvantages of HVF

A
  • expensive
  • very tedious for certain Patietns=fatigue
  • requires a strong knowledge of data interpretation by the examiner
69
Q

Types of screeening

A
  • FDP (frequency doubling perimetry)
  • fast trehshold estimation strategy
  • HVF screening tests
70
Q

Zeus’s FDT

A

Includes realizability indices

  • fixation losses: 6 trials for threshold mode and 3 trials for screening mode
  • both are flagged at 33%
  • false positive in both testing modes
  • false negatives only in threshold mode
71
Q

Zeus’s FDT: patterns

A

Suprathreshold C-20 and C-30 screening

C-20-5 full trehshold
-tests the central 20 degrees at 17 locations

N-30-5 full threshold
-tests all the points of C-20 tests, plus two additional nasal locations for a total of 19 locations

72
Q

Advantages for automated perimetry: screening

A
  • portable and compact
  • affordable
  • no trial lens or eye patch
  • high level of sensitivity of specificity
  • rapid assessment of the field
  • reduced learning curves
73
Q

Disadvantage of automated perimetry: screening

A
  • results limited by cataract and pupils <3mm
  • trouble detecting small scotomas due to the fact that the FDT uses larger test targets
  • offers fewer testing points (17 or 19) vs a HVF
74
Q

Clover leaf pattern

A

Tired

Summer Final: Glaucoma (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions