Tests

Question 0

frequency doubling technology (FDT) perimeter

Answer 0

• tests M (magnocellular) ganglion cell pathway
• cheaper and more portable vs 24-2 or 30-2

“frequency doubling technology”: uses a low spatial frequency (i.e. 0.25 cycles/degree) sinusoidal grating that is undergoing counterphased flickering at a high temporal frequency (i.e. 25 Hz). therefore, spatial frequency of the grating appears doubled

-screening test to detect early glaucomatous visual field defects.

Limits:
uses much larger and fewer stimuli (e.g. only 17 or 19 points tested in the central 30 degrees) compared to standard automated perimetry (SAP).

Question 1

fluorophotometry

Answer 1

used to measure the rate of aqueous humor formation. This procedure involves giving fluorescein either topically or systemically and measuring the decline of concentration of fluorescein in the anterior chamber by optical means.

Question 2

Last part of VF to be affected by end-stage glaucoma?

Answer 2

Central island and inferotemporal VF

Question 3

Equivalent stimulus on Goldmann?

Answer 3

III4e (4mm2)

Question 4

Humphrey Visual Field Degrees between spots?

Answer 4

6 degree grid