I suffer from the exact same thing with the inside corner of my eye driving me crazy at times it itches so bad. What has helped me
is Rx eye drops called
Pataday. It
is for itchy allergy eyes, and sometimes I put a drop or two on the end of a q-tip and dab it in that corner of my eye and sometimes I put the drop directly into the eye. Works wonders. Whether it is allergy or irritation of some sort, the drops take the itch away for me. I hope this works for you.