Elektron Technology HENSON 8000, User Manual, Page: 43 / 159

43 Visual field tests
© 2017 Elektron Technology
3 .2 .2
Fo ve a me a s u re me n t
In the ZATA threshold tests it is possible to measure the sensitivity of the eye
at the fovea. For this measurement the patient fixates the centre of a four-
point pattern of fixation lights positioned below the normal central fixation light.
The softw are uses a 4-2 staircase algorithm to obtain three measurements of
the foveal threshold, and then takes the average of these three readings to
give the final estimate. The 3 measurements are intertw ined to avoid any
obvious sequences.
1. Click and then Yes in the follow ing pop up w indow .
2. Instruct the patient to look at the centre of the four lights, and to press
their response key w hen they see a light flash at the centre of the
pattern. Emphasize that many of the presentations w ill be too dim. If
they are not sure they should not press their key.
3. Click Go to start testing.