Pupil size can be an indicator of autonomic balance.  Smaller means more parasympathetic tone.  In this study they look at electromagnetic acupuncture (EMA) on B15, a point traditionally associated with the heart, and find that there is an increase in parasympathetic activity with this point with EMA, but not with manual acupuncture. I’m pretty surprised at this actually.  I haven’t noticed a difference in autonomic response with varying stimulation (smaller needles, electroacupuncture versus manual).  Have my studies been scientific?  No.  But I’m surprised at their lack of response with manual acupuncture.  I’ll try to get the paper.

J Acupunct Meridian Stud. 2014 Jun;7(3):122-32.

Use of pupil size to determine the effect of electromagnetic acupuncture on activation level of the autonomic nervous system.

Kim SB1, Choi WH2, Liu WX2, Lee NR3, Shin TM2, Lee YH4.

Magnetic fields are widely considered as a method of treatment to increase the therapeutic effect when applied to acupoints. Hence, this study proposes a new method which creates significant stimulation of acupoints by using weak magnetic fields. We conducted this experiment in order to confirm the effect on the activation level of the autonomic nervous system by measuring pupil sizes in cases of stimulation by using manual acupuncture and electromagnetic acupuncture (EMA) at BL15. We selected 30 Hz of biphasic wave form with 570.1 Gauss. To confirm the biopotential by the magnetic flux density occurring in EMA that affected the activation of the autonomic nervous system, we observed the biopotential induced at the upper and the mid left and right trapezius. We observed a significant decrease in pupil size only in the EMA group (p < 0.05), thus confirming that EMA decreased the pupil size through activation of the parasympathetic nerve in the autonomic nervous system. Moreover, we confirmed that the amplitude of the biopotential which was caused by 570.1 Gauss was higher than ±20 μA. Thus, we can conclude that EMA treatment successfully activates the parasympathetic nerve in the autonomic nervous system by inducing a biotransformation by the induced biopotential.