Post cataract surgery ou during which pt was set up for monovision, comes in with outside Rx from her (older age) DO (not OD) which will be her first pair of specs since surgery:

OD Plano -0.75 x 075 Add 2.50
OS -3.00 -0.25 x 105 Add 2.25

I did not work with the patient initially. She was sold poly FT28 in a fairly appropriate-size frame (I can look at the records again tomorrow for exact dimensions and measurements, and I’ll see if the lab can tell me what the BCs and thicknesses were). While I was doing an adjustment for a different pt, I overheard the dispense during which the pt FREAKED. All she could say was that she “can’t see”, throws the glasses down, tries again, “can’t see anything”, glasses down, back on, “I just can’t” which sounds like aniseikonia to me? Would just vertical imbalance cause this sort of nonspecific complaint and intolerance, or would it be diplopia if it were the VI issue? It’s probably pertinent to note that she was fine while closing either eye.

I was able to at least glean the above info re: her history while I finished my adjustment (of course none of this info was obtained by the optician during the initial encounter), but I wasn’t able to sit and troubleshoot like I wanted to. The pt was po’d and just stormed out saying she is going straight back to her doctor, and the optician working with her didn’t ask any questions at all to try to get more info about what she was experiencing or why her dr is neutralizing the monovision, etc. And I wasn’t able to pay enough attention to see if it was the near only or both near and far.

Anyway, my questions are these:
1) How do/would I know if it was both aniseikonia AND VI?
2) If it’s both, would our only option (besides contacts) be SV? Are there any multifocals at all that could be iseikonic and also account for vertical imbalance? If so how do you calculate magnification of the seg and/or slab off?
3) If it’s only VI, would slab off suffice?
4) What is the typical threshold for magnification difference causing aniseikonia in this type of situation (sudden change d/t cataract surgery)?
5) What is the lower add power OS supposed to accomplish? Was that an attempt at compensating for VI?? I spoke to the DO’s office to get more info but they had no idea what I was talking about; all they could tell me was the different add powers OD/OS were correct, and that they had no record of any previous glasses, and that “maybe she had amblyopia”. Ugh.
6) Is it normal to set one up with monovision with an extra 3.00 D plus power in the near eye? If with the monovision her near focal distance is just too short for her, is there any chance that using the above Rx except change OS sphere power to -0.50 would work? (Hypothetically of course! I know that’s not up to me. Just wondering about the concept.)

Can someone wise explain all this to me?

Thank you sooooooooo ridiculously much!!

P.s. Can someone also explain to me why VI is a thing for FT28s when the lens has a distance OC AND a seg OC? My brain is just all over the place and it won’t rest until I have a good grasp on these concepts! Also, If I’m wrong on anything I’ve written, please tell me! :)