Visual Fields and Glaucoma (M)

Question 1

What must you be aware of if the MD is positive?

Answer 1

1. false positives

2. ignore PD plot

Question 2

What are the steps to interpret a visual field?

Answer 2

1. assess reliability
2. rule out artifacts
3. compare to normative database
4. correlation of VF loss with other exam findings

Question 3

What is the acceptable percentage of fixation losses? 1. False positives? 2. False negatives? 3

Answer 3

1. less than 20%
2. less than 15%
3. less than 33%

Question 4

What type of ganglion cells are more responsive to low spatial frequencies and high temporal frequencies?

Answer 4

magnocellular

Question 5

How many points are tested in a 24-2? 1. How far apart are the points? 2. What is this test best for? 3

Answer 5

1. 54
2. 6 deg apart
3. glaucoma (30deg nasal, all other 24)

Question 6

What defines a statistically significant global field loss? 1. What is a perfectly normal value for this? 2

Answer 6

1. any three contiguous points flagged as abnormal with at least one box outside the 99% confidence interval
2. 100%

Question 7

What cones does the SWAP target? 1. Is it better or worse for glaucoma detection? 2

Answer 7

1. blue cones

2. 5 years earlier detection

Question 8

What are the different type of testing patterns that can be used for visual field testing in glaucoma management?

Answer 8

1. 30-2
2. 24-2
3. 10-2

Question 9

What is the amount of mean deviation that is acceptable?

Answer 9

more than -2dB (more minus)

Question 10

What is the amount of visual fields that should be obtained within the first two years of diagnosis?

Answer 10

3 tests per year in first two years

Question 11

What are the characteristics of an advanced defect using the Glaucoma Staging System?

Answer 11

1. MD -10dB to -20dB for 24-2
2. pattern deviation plot with 50 to 74% of points depressed below 5% level and 25 to 49% of points depressed below 1%
3. any point within central 5deg with sensitivity below 0dB
4. both hemifields containing a point with sensitivity below 15dB within 5deg fixation

Question 12

What is the depression after the test is normalized for any uniform depression throughout the whole field called? 1. What is a perfect score? 2

Answer 12

1. pattern standard deviation

2. 0

Question 13

What are FDT’s used for? 1. What are the problems? 2

Answer 13

1. screening of glaucoma

2. false positives (especially in kids)

Question 14

How many points are tested in a 30-2? 1. How far apart are the points? 2. What is this test best for? 3

Answer 14

1. 76
2. 6 deg apart
3. neuro problems

Question 15

What is the limit of the amount of visual fields that can be done according to medical insurance?

Answer 15

every 3 months

Question 16

What are the different type of instruments that can be used for visual field testing in glaucoma management?

Answer 16

1. Humphrey visual field analyzer
2. Octopus 300, 600, 900
3. FDT/Matrix

Question 17

What type of ganglion cells does FDT activate?

Answer 17

magnocellular (larger)

Question 18

What is the major functional difference between SITA-standard and SITA-fast? 1. What does SITA-fast result in more of? 2

Answer 18

1. threshold crossed from both sides in standard and only once in fast
2. test/retest variability and exaggerate a defect

Question 19

What rate of progression during the guided progression analysis (GPA) is problematic?

Answer 19

greater than 1%

Question 20

Does glaucomatous damage respect the vertical or horizontal midline?

Answer 20

horizontal

Question 21

What are the different type of testing strategies that can be used for visual field testing in glaucoma management?

Answer 21

1. SITA standard or SITA fast (Humphrey)

2. TOP (Octopus)

Question 22

What type of ganglion cells are more responsive to high spatial frequencies and low temporal frequencies?

Answer 22

parvocellular

Question 23

What are the roles of visual fields in glaucoma?

Answer 23

1. determine presence/absence of functional loss
2. quantify degree of functional loss
3. assess effectiveness of IOP lowering therapy
4. determine rate of progression of VF loss

Question 24

How can a high negative mean deviation be inflated?

Answer 24

1. many slightly depressed points

2. few greatly depressed points

Question 25

What are the characteristics of an early defect using the Glaucoma Staging System?

Answer 25

1. MD less than -6dB for 30-2 or less than -5 for 24-2 AND one of the following:
2. pattern deviation plot with cluster of 3 or more points in expected location of VF below 5% level with one below 1% level
3. pattern standard deviation P less than 0.5
4. GHT “outside normal limits”
5. less than 25% of points that are less than 5% on pattern deviation plot
6. all points in central 5deg are greater then 15dB

Question 26

What is the rate of VF per year taken for someone with low to moderate risk of glaucoma? 1. High risk? 2

Answer 26

1. test once per year or sooner if event

2. test twice per year

Question 27

What is the global index that is more representative of ganglion cell density instead of overall reduction of VF?

Answer 27

visual field index (VSI)

Question 28

What are the characteristics of an severe defect using the Glaucoma Staging System?

Answer 28

1. MD -20dB or worse
2. pattern deviation plot with 75% of points depressed below 5% level and 50% of points depressed below 1%
3. 50% of points within central 5deg with sensitivity below 0dB
4. both hemifields containing greater than 50% of points with sensitivity below 15dB within 5deg fixation

Question 29

What are the characteristics of an moderate defect using the Glaucoma Staging System?

Answer 29

1. MD less than -12dB for 30-2 or less than -10dB for 24-2 AND one of the following:
2. pattern deviation plot with 25 to 49% of points depressed below 5% level and 15 to 24% of points depressed below 1%
3. At least 1 point within central 5deg with sensitivity of less than 15dB but no point in central 5deg less than 0dB
4. only 1 hemifield containing a point with sensitivity below 15dB within 5deg fixation