Visual fields

Question 1

visual fields

Answer 1

Widest temporally
 Island of vision
 The blind spot is 15 degrees from fixation (corresponding to the displacement of
the optic nerve from the fovea)

Question 2

normal field extents

Answer 2

 90-100 degrees temporally
 60 degrees nasally
 70-80 degrees inferiorly
 50-60 degrees superiorly

Question 3

kinetic perimetry

Answer 3

GVF
 Usually done manually
 “Slices” the island of vision into isopters which can be plotted

Question 4

GVF

Answer 4

 Controller on machine allows selection of stimulus size and illumination
Patients sit oppority a white hemipshereical bowel with fixation at 33cm

Question 5

GVF maximum brightness

Answer 5

1000 apostilbs

Question 6

GVF roman numerals

Answer 6

I - V
size in diameter, 1/2 each time
II = 1mm2
III = most commonly used
V = biggest target

Question 7

GVF number

Answer 7

1- 4
brightness of the stimulus
drop = 5dB

Question 8

GVF letter

Answer 8

a-e
finer calbirations of brightness
drop 1 Db

Question 9

GVF plot

Answer 9

Armaly Drance technique used to plot:
o Concentrates on nasal horizontal
o Tests pericentral area with a suprathreshold stimulus to exclude central
scotomas

Question 10

Luminosity range

Answer 10

0.08 to 10,000 apositlibs
Inverted scale
0 to 52 ab

Question 11

Static threshold perimetry

Answer 11

 Measures the “thickness” of the island
 Lighter grayscale indicates thicker areas of better vision and darker/black areas
indicate poor vision
 Humphrey, Octopus etc.

Question 12

Finds threshold at

Answer 12

the intensity of light seen 50% of the time

 Measured in decibels of attenuation of the light
 Light presented for less than 0.5 second
 White target on white background: achromatic

Question 13

maximum brightness

Answer 13

10,000 apostilbs

Question 14

benefits of HVF

Answer 14

standardised
less user depednant
numerical output

Question 15

HVF 24-2

Answer 15

evaluates 24 degrees with 54 points

Question 16

HVF 10-2

Answer 16

evaluates 10 degrees with 68 points

Question 17

HVF 30-2

Answer 17

evaluates 30 degrees with 76 points

Question 18

how much of the visual cortext relates to the central visual field

Answer 18

80%
thf central 24 correlates to 30 degrees

Question 19

central 10 degrees is best for

Answer 19

paracentral scotomas

Question 20

global indicies

Answer 20

Summary of results condensed into one figure, mainly used to monitor
glaucoma progression

Question 21

total deviation

Answer 21

Deviation of patient’s result from age-matched controls

Question 22

mean deviation

Answer 22

Average deviation of sensitivity from age adjusted normal population

Question 23

pattern standard deviation

Answer 23

Average deviation from the normal hill of vision after correcting for overall
sensitivity differences

Question 24

corrected PSD

Answer 24

PSD after accounting for short-term fluctuation (an indication of consistency
achieved by testing ten points twice and assessing the difference)

Question 25

fixation loss in HVF

Answer 25

patient responds to a target presented at their blind spot

Question 26

false-negative in HVF

Answer 26

atient fails to respond to a suprathreshold target at a location that is expected to be seeing

Question 27

false positve in HVF

Answer 27

the machine makes a familiar noise and alters the motorised light but does not present a target and the patient responds as if seeing one (trigger-happy

Question 28

perimetric errors

Answer 28

miotic pupil cloveleaf deaf - malingering lens rim arterfact refractive error

Question 29

Unilateral central scotoma

Answer 29

 Optic nerve pathology: compressive lesions, optic neuritis  Macular pathology: scarring, oedema, etc

Question 30

Bilateral central scotoma

Answer 30

 Optic nerve pathology: toxic/nutritional  Macular pathology: scarring, oedema etc.

Question 31

Causes of cecocentral scotoma

Answer 31

pathology extending from disc to macular or vice versa).As above, same as the causes of central scotoma, but in addition: o Optic disc pit with serous detachment o Inherited optic disc pathology: Leber's, autosomal dominant optic atrophy etc.

Question 32

arcuate scotoma

Answer 32

damage to nerve fibre bundles that extend to the blind spot) o Glaucoma o Anterior ischemic optic neuropathy o Branch retinal artery/vein occlusion o Optic nerve drusen

Question 33

altituidinal defect

Answer 33

this is a defect that respects horizontal midline and is characterised by damage to the optic disc poles o Hemiretinal artery/vein occlusion o Optic neuritis o Anterior ischemic optic neuropathy

Question 34

binasal defect

Answer 34

o Glaucoma in most cases o Compression of the temporal optic nerve/chiasm o Internal carotid artery aneursym o Infarction