Visual Fields

Question 1

How can visual field be measured?

Answer 1

Confrontation
Amsler - for central visual field
Static - target is stationary - Humphrey
Kinetic - target is moving - Goldmann
Flicker based fields

Question 2

What is the methodology for stating and kinetic tests

Answer 2

PAtietns need to detect stimulus of given size and intensity on a uniform b/g

Patients keep one eye fixed ona target directly forward while other eye is covered

Test object is presented to the test eye at various position

Patient signals when they see thses objects

Areas of perception deficits are idicative of VF defects

Question 3

How is the goldmann field test carried out?

Answer 3

A target of fixed size and luminance is moved from the periphery to the centre

Question 4

What is the goldmann test good for?

Answer 4

Good for detecting and monitoring neurological definitcis - covers a wider VF than static tests
Good for pts with poor fixation and patietns in whom malingering is suspected

Question 5

Disadvantages of golmann test

Answer 5

Staff members need ot be trained
LEss useful for producing reporducible fields
Takes longer

Question 6

What is the humphrey visual field?

Answer 6

Automated static perimetry

A static stimulus is presented at 25dB for 0.2seconds at random locations across central 30 degree VF
If the stimulus is seen the luminance is reduced in discrete steps until it is nolonger seen

Question 7

What are the advantages of the Humphrey VF

Answer 7

STandard conditions and reproducible
Automated
Analysis package
Results are reported in statistical terms compared to normal age matched sighted people

Question 8

What are disadvantages of Humphrey VF

Answer 8

Only central 30 degrees of VF examined