Visual fields

Question 1

If there is a generalised decrease in in sensivity, where is the likely location of defect?

Answer 1

• Media opacity (cornea, lens or vitreous)
• Decreased attention

Question 2

If the visual field loss pattern is a central scotoma, where is the likely location of defect?

Answer 2

Macula or optic nerve

Question 3

If the visual field loss pattern is a cecocentral scotoma, where is the likely location of defect?

Answer 3

Papillomacular nerve bundle or nearby retina in region between macula and ONH

Question 4

If the visual field loss pattern is a arcuate scotoma, where is the likely location of defect?

Answer 4

Arcuate retina ganglion cell nerve fibre bundles or retinal vasculature

Question 5

If the visual field loss pattern is an arcuate scotoma, where is the likely location of defect?

Answer 5

Arcuate retina ganglion cel nerve fiber bundles or retinal vasculature

Question 6

If the visual field loss pattern is a temporal wedge, where is the likely location of defect?

Answer 6

Nasal retina radial fibres entering the optic nerve

Question 7

If the visual field loss pattern is a blind spot enlargement, where is the likely location of defect?

Answer 7

Optic nerve

Question 8

If the visual field loss pattern is multiple scattered defects, where is the likely location of defect?

Answer 8

Retina

Question 9

If the visual field loss pattern is hemifields respecting the horizontal meridian, where is the likely location of defect?

Answer 9

Retina ganglioon cell nerve fibre bundles or less commonly retinal vasculature

Question 10

If the visual field loss pattern is hemifields respecting the vertical meridian, where is the likely location of defect?

Answer 10

Optic chiasm or posterior visual pathways

Question 11

If the visual field loss pattern is bitemporal, where is the likely location of defect?

Answer 11

Optic chiasm

Question 12

If the visual field loss pattern is homonymous, where is the likely location of defect?

Answer 12

Optic chiasm or optic radiations

Question 13

If the visual field loss pattern is congruous bilateral defects, where is the likely location of defect?

Answer 13

Nearer to the posterior visual cortex

Question 14

If the visual field loss pattern is incongruous bilateral defects, where is the likely location of defect?

Answer 14

Nearer to the optic chiasm

Question 15

If the visual field loss pattern is a pie in the sky, where is the likely location of defect?

Answer 15

Temporal lobe

Question 16

If the visual field loss pattern is a pie on the floor, where is the likely location of defect?

Answer 16

Parietal lobe

Question 17

What is a typical “normal” dB reading?

Answer 17

30 dB

Question 18

What does a dB value of 0 mean?

Answer 18

If dB = 0, the patient could not see the brightest target

Question 19

Examples of pathologies which may depress hill of vision?

Answer 19

• Cataracts
• Vitreous haemorrhages
• Diffuse media opacities

Question 20

What is the GHT value on visual field results?

Answer 20

Glaucoma Hemifield Test compares points in the upper field to corresponding points in the lower field and interprets the results as:
a) Outside normal limits (which supports upper and lower fields are different and may signfiy glaucoma)
b) Borderline
c) Within normal limits (indicating glaucoma may not exist)

Question 21

What is the PSD value on visual field test results?

Answer 21

The Pattern Standard Deviation (PSD) provides information about localised loss. High PSD = non-uniform sensitivity loss (therefore not due to diffuse depression from cataract or vitreous haemorrhage)

Question 22

What is the MD value on visual field test results?

Answer 22

The Mean deviation (MD) is the average difference from normal expected value in the patients’ age group.

MD of -2 or less, typiclaly could indicate glaucoma