Many years ago when I was thinking of getting it done I was told by the sales rep/doctor (I forget) the machines are limited in range. Women tend to have larger pupils than men apparently this wasn't thought of during the design phase. Kind of weird to go through all that trouble of designing and building a machine that needed just a few more millimeters of range. I passed on the procedure.
Tangentially - there was something I heard on the radio recently that drug testing was restricted by the FDA about 30 years ago to men only due to unforseen side effects possible in pregnant women, and medical companies took the shortcut of just limiting testing to men wherever possible and lifting that thought process is still an ongoing effort. It even impacts animal testing where they might test something mostly in male mice.
