Ah, please forgive me. I get used to looking at many things and forget that it was reading the words in the book that was often my first question too. Forgive me. I completely forgot that was part of the icon when I was trying to understand what you meant.
My reading in Byzantine script is just awful, lol. They use a kind of shorthand, and non-standard writing. I can get the sense of it, slowly and with effort, but directly translated it doesn't work out perfectly. And TBH, it would take time I don't have at the moment to work out the rest of it. I've got about 3/4 though.
It's one of the I Am statements - often in the books Christ holds.
This one says ... unless I mistake .... I Am the Shepherd, .... Good Shepherd (reverse order - Shepherd good) ... life ... ... to (for) sheep.
I think proper translation would probably work out to - I Am the Shepherd - the Good Shepherd lays down His life for the (insert another word/s?) sheep.
So sorry. I'm afraid I'm used to standard typography when reading, and Byzantine gives me fits.
And so sorry I misunderstand your question.
(Also now I'm curious myself about that extra word, so I will ask around, if you're interested.)