I am pleased with my bit of photoshop finagling. There is the problem of glasses glare - we were well aware of this during the shoot. Having achieved the Elimination of Blinking trick (as described in a previous post) I thought I'd try the photo merging technique on glare elimination.
The two original photos, to the right: Glasses On and Glasses Off, were taken in rapid succession. Stay absolutely still and take glasses off, I instructed. As it turned out, she moved slightly, but no problem. I cut out each eye separately from the Glasses Off pic (Using rectangular selection tool, I grabbed each eye along with enough face to fill in each lens).
I layered the Glasses On pic Over each of these Glasses Off eye layers. Reduced the opacity of Glasses On layer to 70%, and moved the individual Glasses Off eyes around so tear ducts/ eye corner lined up with what I could see of the Glasses On photo. Turned Glasses On opacity back to 100%, then used eraser (with fuzzy edges) to remove the Glasses On lens area suffering from glare, revealing beneath, the Glasses Off, Glare Free eyes.
It's way simpler than it sounds.