We don't usually bother with lights, but have had ferrets with numerous eye
exams, and sometimes run a flashlight for them.  Turns out that almost all
we've known over the last 18 or so years LOVE having lights shown in their
eyes.  Really ENJOY it BIG time
(Bill-the-ferrets'-demi-god-who-won't-admit-it pun intended).
 
Strange -- but then we are talking FERRETS!  :-)
[Posted in FML issue 3106]