If you’re focusing on the right thing (your sights), the target will be slightly out of focus anyway.

One description I found said that the lens part of her glasses contains an adjustable “iris that can be adjusted to change the perceived depth of field” - which sounds to me like an adjustable aperture in photography. With a smaller aperture (larger f-number in photography) I believe she would potentially be able to have both the sights and the target in focus? Otherwise I’m not sure what the point would be.

Edit; Oh - and the elephant is her daughter’s. :-)