Doctors Paez, Isenberg and Apt, in their study of torsion and elevation under surgical plane general anesthesia, and during voluntary Ud closure, provide useful baseline data in normal adults. Of particular interest is that the torsional position of the eye changes only minimally from the awake state to the surgical plane of general anesthesia, about 2 to 2Vfe degrees of extorsion, on the average.
I became interested in this several years ago when beginning to do Harada-Ito procedures under either general anesthesia or retrobulbar anesthesia in adults. In seeing little or no alteration in the torsional position of the fundus by either mode of anesthesia, I used the position of the fundus to judge how much torsional effect to produce by an intraoperative adjustment of the Harada-Ito sutures, with gratifying results. Although I now place these on adjustable sutures for adjustment postoperatively, I still use the indirect ophthalmoscope to judge the amount of torsional effect I am creating at the time of surgery.
I have had the disconcerting experience on several occasions, however, of seeing abnormal preoperative torsion disappear under anesthesia in children. There were usually cases of overacting inferior obliques showing significant extorsion by indirect ophthalmoscopy preoperatively, with no abnormal torsion under general anesthesia. I no longer trust, therefore, the absolute torsional position of the fundus under anesthesia, at least in children. I would encourage the authors, in extending their measurements to cases with ocular motility disorders, to include children as well as adults, and perhaps to use fundus photography to document the absolute torsional position of the fundi.
It is refreshing to see a systematic study being made of this problem, instead of the usual case-by-case clinical impressions which most of us tend to rely upon. I hope the authors will indeed continue this work.