6 Device Description
Instruction Manual Mesotest II (G/62800/0715/en) 13 / 86
The ambient light and the glare light are illuminated separately by one
light emitting diode each.
A stand-by function switches off the illumination after a certain time if
no entries are made by the operator.
Fixation aid
A projection device for a fixation aid is located over the test field. Two red
dots can be projected onto the test field with this device, if necessary.
If the patient looks directly into the glare light when the switch-over to
mesopic vision is made, he will no longer be able to see the optotypes, to
begin with. This can lead to a delay in the examination procedure, as he
needs some time (approx. 10-30 seconds) to readapt.
Test procedure
Control Pad: The contrast levels are each presented with and without
glare. As such, a total of eight consecutive tests are conducted.
The visual requirement is deemed to be met when the patient has
recognised at least 3 of 5 positions of the Landolt ring (60% criterion).
Mark this accordingly on the test sheet.
Fig. 6-4: Fixation aid
Test no. 1 2 3 4 5 6 7 8
Contrast 1:23 1:5 1:2.7 1:2 1:23 1:5 1:2.7 1:2
Glare light off off off off on on on on
Prespecified position of
the Landolt ring
TL TR T B BR B BL T
Function Test mesopic vision Test mesopic vision with glare
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