It sounds like you have done an excellent job of trying to find the answer. Perhaps her eyes
are bothering her for some reason (allergies
, atopic conjuctivitis, headache due to viral illness or strep throat, dry air from heater in house, other???? As she gets older, eventually the ophthalmologist will be able to get a better exam and possibly discover some problem causing eye irritaton. Sometimes children blink a lot for no good reason or some reason that you can never discover.