Lecture 3b- PERG (The pattern ERG)

Question 1

How is the PERG recorded

Answer 1

using a counter-phasing (reversing) chequerboard stimulus

Question 2

What is the mean luminance of the PERG

Answer 2

The mean luminance remains constant at all times and is typically 50 cd/m-2

Question 3

What is the most important parameter of the PERG

Answer 3

Contrast

It is highly dependent on good focus

Question 4

Are pupils dilated for the PERG

Answer 4

No because they need to be reactive and able to focus

Question 5

More on pupils and PERG

Answer 5

contrast-reducing optic opacities e.g.
cataracts should be characterised for
potential impact).

Question 6

What area does the PERG stimulus cover

Answer 6

The whole macular region

Question 7

How does the PERG compare to the mfERG

Answer 7

its not as spacially selective

Question 8

Whats a pro of the PERG

Answer 8

quick and easy to record

Question 9

What size is the PERG retinal response

Answer 9

tiny and ~5 µV in amplitude

Question 10

What can the PERG differentiate between

Answer 10

It differentiates macular / optic nerve
disease

Question 11

What are the components of the PERG

Answer 11

P50= macular function
N95= retinal ganglion cell function

Question 12

What types of patients is the PERG unsuitable for

Answer 12

Nystagmus and under 6 year olds

Question 13

What is the N95 amplitude dependent on

Answer 13

the p50 amplitude

Question 14

What PERG results are seen in maculopathy

Answer 14

reduced P50 and N95

Question 15

What PERG results are seen in optic neuropathy

Answer 15

Attenuated N95