hvf

Question 1

Instruction of fovea threshold

Answer 1

can you see the diamond of 4 lights
look at the centre of diamonds and click the button if you see light flashing
we will start now

Question 2

instruction of gaze initialisation

Answer 2

can you see the orange light at the centre
the orange light is your target, keep looking at the orange light, you can blink a few times and hold your blink for 10s the test will start now

Question 3

instruction of test

Answer 3

this is our last test, can you still see the orange light, keep looking at this orange light and click the button if you think you see lights flashing on the bowls . throughout this test you can blink normally, and if you need break press and hold the button. this test is about 3-4 mins once ready we will start now

Question 4

purpose of hvf

Answer 4

to test central and side vision

Question 5

Probability data

Answer 5

Less than _ percent of the population in the age group has this value but it is still considered normal

Question 6

GHT and purpose

Answer 6

compare the upper and lower VF according to common glaucomatous VF defect in 5 region

Purpose: Check for glaucoma VF defect

Question 7

VFI and purpose

Answer 7

VFI is the summarize visual field status as a percentage of normal age corrected sensitivity by taking into account of the ganglion cell density.

Purpose: is to represent ganglion cell loss

Question 8

PSD and it’s purpose

Answer 8

PSD is the average deviation of the pattern deviation which reflects irregularities in the field caused by localized visual field defects due to non-linear value it should not be use in the staging of visual field it also unable to write information of advance glaucoma

Purpose: to check for the presence of localize defect

Question 9

MD and it’s purpose

Answer 9

MD is the average value of the total deviation when comparing the threshold back to the normative database. A positive value means patient perform better than normal and a negative value means patient perform worse than normal

Purpose: to compare the total deviation to see how much the patient deviate from the normative database over time helping with staging visual field loss and measuring change over time

Question 10

Gaze tracker deflects

Answer 10

upward : fixation loss, fixation stability

downward: blink interference by lid or lash

Question 11

False negative definition and cut off

Answer 11

patients is able to respond to dim light at a specific spot but when a brighter light is flashed the patient did not respond to it

Cut off: <20%

Question 12

cause of false negative

Answer 12

• Inattentive patient
• Fatigue patient
• Or in advance glaucoma

Question 13

causes of false positive

Answer 13

• Patient do not understand the instruction
• Malingerers
• Hear the machine Trigger happy happy press button

Question 14

false positive and cut off

Answer 14

patient response to light even when there is no stimuli shown
Cut off: <15%

Question 15

cause of fixation loss

Answer 15

Wandering eye,
the patient placed on wrong chin rest
wrong occlusion
poor fixation

Question 16

fixation loss and cut off

Answer 16

by flashing light on the blind spot

Is when there is patient response to the light when the light is flashing on the blind spot , cut off : <20