12 - VF special topics

What VF defect is caused by a junctional scotoma?

ipsilateral defect to affected ON

ST lesion to contralateral eye

What causes a junctional scotoma?

lesion at the junction of the ON and anterior chiasm

What VF defect does a lesion to the optic nerve cause?

full VF defect in the ipsilateral eye

What VF defect does a lesion to the chiasm cause?

bitemporal hemianopsia

What VF defect does a lesion to the optic tract cause?

incongruous contralateral homonymous hemianopia

What is the benefit to SWAP?

may be more sensitive to early glaucomatous field loss

Which type of perimetry should be used for glaucoma monitoring?

standard perimetry

What are the downsides to SWAP?

1. more fixation losses

2. longer test/slower reaction times

What is the only pattern available for SWAP?

24-2

What stimulus does frequency doubling use?

grating with low spatial frequency and high temporal frequency → wide bars that flicker fast

What retinal pathway does frequency doubling target?

magnocellular pathway → motion and flicker detection

Why was frequency doubling theorized to work in glaucoma?

thought that the largest ganglion cells (which are sensitive to fast flicker) have less overlap/redundancy → decreases in sensitivity to fast flicker may be a sensitive way to detect signs of early glaucomatous damage

What stimulus does the Humphrey matrix perimeter use?

same stimulus as FDT, but small squares for increased spatial resolution

what is the Humphrey Matrix Perimeter intended for?

more than just a screening instrument → monitor progression

what does Pulsar perimetry use as a stimulus?

bullseye pattern (alternating black and white pattern that flickers) → same as FDT

what is the rationale for SWAP, Flicker and Pulsar perimetry?

overcome redundancy of the visual system by selectively stimulating a subset of retinal cells

What is the Esterman VF test?

binocular version VF using bright stimulus and 120 points of peripheral and central visual field and records whether or not each stimulus has been seen

patient wears their habitual distance specs with no additional near refractive correction

Why does the Esterman VF test use such a bright stimulus?

so that any refractive blur will not affect test results since patients are not corrected for near

What is the Esterman VF test often used for?

measure functional vision → used as a driving test

What is a disadvantage to the Esterman VF test?

only one stimulus intensity (bright) so cannot quantify the depth of a defect

What are the potential advantages of VR based VF testing?

1. cheaper

2. takes up less space

3. patients can monitor at home