START
If the rings are not symmetrical,
the probe does not point
perpendicularly to the center of
your eye. Correct the position of
the tonometer.
Keep both eyes
open. Covering
the eye not being
tested may help
you see the rings
more clearly.
START
5 mm
Shorten the supports by rotating them
clockwise two clicks at a time until you only
see a symmetrical green ring. The tonometer is
now at the correct distance from your eye.
11