It has generally been assumed that the eye rotates
upward during eye blinks, thus generating a potential
analogous to a vertical eye movement.6-8 However,
Matsuo and his colleagues were unable to see eye
movement or record an eye blink potential from a
patient with unilateral total facial nerve palsy. The
blink potential from the non-paralysed side was
normal.3 Unfortunately the data in this report do not
aid in resolving this controversy. It is of some interest,
however, that our blind subject generated a larger
response when looking down than when looking up.
When asked to look up as far as possible he generated
a response only 20% larger than those shown in Fig.
4. In comparison with our normal subjects his eye
blink response amplitude was also much smaller. This
suggests, although it does not prove, that eye movement
does occur during the blink response. If, as
Matsuo et al. suggest, the response is produced by a
wiping action of the eyelid over a stationary cornea,
one would assume that the absolute magnitude in this
subject would have been larger and similar to the
amplitude of response from combined upward and
downward movement.