Visual field defects

Question 1

what is static perimetry?

Answer 1

location of the stimulus is constant
Intensity increases/decreases

Question 2

what is kinetic perimetry?

Answer 2

Intensity contant
Location of target moved from non-seeing to seeing

Question 3

what are the 2 types of static perimetry?

Answer 3

1. Threshold
2. Suprathreshold

Question 4

What is an example of a threshold test?

Answer 4

ZATA

Question 5

how does a threshold strategy work?

Answer 5

each location is thresholded using a staircase procedure

Question 6

Advantages of threshold strategy?

Answer 6

• sensitive to shallow field loss
• VF progression
• allows statistical analysis
• provides info about reliability

Question 7

Disadvantages of threshold strategy?

Answer 7

• time consuming: newer methods offer a comparable time

Question 8

Advantages of supra threshold strategy?

Answer 8

• speeds up investigation
• good screening test
• no need for specialist training

Question 9

disadvantage of supra threshold strategy?

Answer 9

• insensitivity to shallow field defects
• can miss defects if threshold is measured incorrectly

Question 10

which condition do you get shallow field defects?

Answer 10

POAG

Question 11

what is an example of static perimetry machines?

Answer 11

1. Humphrey field analyser
2. modern Henson models

Question 12

Which VF test can be carried out routinely as part of a screening process?

Answer 12

gross perimetry/confrontation

Question 13

if unable to use glasses, how do you correct the patient on the machine?

Answer 13

use closest BVS to the reading rx

Question 14

when do you correct for cyls when doing VFs?

Answer 14

if = or > 1DC
use full correction

Question 15

if rx 8D or higher, od you use glasses or CLs?

Answer 15

use CLs if possible

Question 16

When do you use an Amsler chart?

Answer 16

• suspicious macula
• unable to see macula
• CSR
• neovas
• CMO
• ERM

Question 17

what distance do you use the Amsler?

Answer 17

28-32 cm

Question 18

do you use correction when doing Amsler?

Answer 18

yes - use near rx

Question 19

Limitations of Amsler?

Answer 19

only detects 50% of patients with macular disease

Question 20

how many different types of Amsler charts are there?

Answer 20

7

Question 21

Which Amsler chart is this and when is it used?

Answer 21

Chart 1 - Standard chart which must be used in every case and in many cases is sufficient

Question 22

Which Amsler chart is this and when is it used?

Answer 22

Chart 2 - used when central point is not seen as the diagnoal lines help to fixate the centre of the square in spite of central scotoma

Question 23

Which Amsler chart is this and when is it used?

Answer 23

Chart 3 - used in cases of colour scotoma

Question 24

Which Amsler chart is this and when is it used?

Answer 24

Chart 4 - reveals only the scotoma - nothing is distorted

Question 25

Which Amsler chart is this and when is it used?

Answer 25

Chart 5 - looked at horizontally and vertically. It will show metamorphopsia

Question 26

Which Amsler chart is this and when is it used?

Answer 26

Chart 6 - used for metamorphopsia again but thinner lines allow for more minute examination of distortion

Question 27

Which Amsler chart is this and when is it used?

Answer 27

Chart 7 - used for more minute examination of the central area where the rectangle with subdivided squares indicates the limits of the fovea.
GOOD FOR HIGH MYOPES WHEN HELD AT THE PUNCTUM REMOTUM OF THE UNCORRECTED EYE