Visual Field Testing Strategies

Question 1

types of visual field testing strategies (general)

Answer 1

• kinetic

- static (supra-threshold and threshold)

Question 2

where do you move the stimulus in kinetic testing strategy?

Answer 2

move the stimulus from non-seeing to seeing (approach the HOV horizontally)

Question 3

what points do you plot with kinetic testing?

Answer 3

plot points where the stimulus is first seen- all points are of equal sensitivity

Question 4

in kinetic VF testing, what is the “plot of points of equal sensitivity connected by a line” called?

Answer 4

isopter line

Question 5

advantages of kinetic perimetry

Answer 5

• rapidly evaluate peripheral VF
• rapidly plot deep defects
• quick, accurate for steep bordered defects
• maybe useful in characterization of neurological defects (they do not cross vertical midline)

Question 6

disadvantages of kinetic perimetry

Answer 6

• compromised ability to detect scotomas
• no system to quantify results
• difficult to recognize early field defects
• examiner influence on procedure if manual, must be well trained

Question 7

description of a type of defect where kinetic perimetry is good for

Answer 7

deep, steep bordered VF defects due to the very abrupt change in sensitivity at the border of the VF defect (very narrow zone of uncertainty)

Question 8

description of a type of defect where kinetic perimetry is not good

Answer 8

VF defects with sloping borders, wide zones of “uncertainty” and highly variable patient responses when plotting the borders of VF defects with sloping borders

Question 9

examples of some diseases that could cause steep-bordered, deep VF defects

Answer 9

• physiological blindspot
• retinoschisis
• some retinal detachments
• many advanced diseases such as retinitis pigmentosa, stroke involving visual pathways, advanced macular degeneration

Question 10

how is an absolute VF defect (based on depth) defined?

Answer 10

no sensitivity, cannot see the brightest available (0dB) stimulus on that particular instrument

Question 11

how is a relative VF defect (based on depth) defined?

Answer 11

sees some stimuli but not dimmer or smaller stimuli

Question 12

how is a sloping VF defect (of the border) defined?

Answer 12

gradual change in VF defect from less sensitivity to greater sensitivity

Question 13

how is a steep VF defect (of the border) defined?

Answer 13

rapid change in sensitivity at the edge of a VF defect: sensitivity drops rapidly at the edge of the VF defect

Question 14

type of VF defect that is an area of reduced sensitivity surrounded by higher (but not necessarily normal) sensitivity

Answer 14

scotoma

Question 15

type of VF defect that is an area of reduced sensitivity extending into the VF fro the edge of the VF

Answer 15

depression

Question 16

what is generalized depression?

Answer 16

all sensitivities in the VF are reduced (including sensitivity at fixation (foveal sensitivity)

Question 17

type of VF defect that is an absolute loss of sensitivity extending into VF from the periphery and the edge of VF is shifted inward towards fixation

Answer 17

contraction

Question 18

what variable changes in automated or computerized threshold perimetry

Answer 18

only the stimulus brightness is varied to determine the just detectable level

Question 19

in suprathreshold perimetry, the same stimulus intensity is used at all test points, but what is varied?

Answer 19

stimulus intensity is varied by test location (eccentricity compensated) and varied depending on the expected thresholds at each location (threshold-related)

Question 20

what would occur if you only used single intensity supra threshold strategy?

Answer 20

if the same stimulus intensity is used at all points in the VF, often the stimulus is not adequately supra threshold at 20-40 degrees so you see artifactuous misses near edge of VF or stimulus too supra threshold in central 10 degrees so you miss shallow central defects near fixation

Question 21

contrast static threshold perimetry with supra threshold tests

Answer 21

• mich more time consuming
• better sensitivity
• worse specificity- many normals show areas that look like VF defects
• more difficult to interpret

Question 22

what is superior for the detection of early glaucomatous VF loss

Answer 22

static threshold perimetry

Question 23

which types of stimulus are adequate for detection of early glaucomatous VF loss in glaucoma suspects

Answer 23

• alternative forms of perimetry (FDT, Matrix, HEP)

- white on white NOT ADEQUATE