Hi Cathy,
Remember that low estrogen levels can cause occular problems.  If she hasn't
resumed menstruation, perhaps her prolactin levels are still high enough
that estrogen suppression is going on.  Also, I have so many perimenopausal
moms -- late comers to child bearing who are going right into early
menopause with all it's issues.  Among them, for me at least, was
considerable occular dryness and irritation.  If infant is nursing only a
few times a day, wonder if oral contraceptives with some low doses of
estrogen would help.
Barbara

PS I really liked the comments about the connection between the action of
the tongue and jaw during clamping.  I think you are absolutely on the money
on that.