What does it mean to have peeling ilm?

See below. The internal limiting membrane is the most superficial layer of the retina that is peeled during vitrectomy surgery to better treat conditions like macular hole (better chance of closing it) and macular pucker (lesser chance of it regrowing in the future). You don't need this layer for good vision.
A retinal procedure. The internal limiting membrane is the natural layer of the retina that lies closest to the center of the eye (the interior). When someone has swelling of the macula, or a macular hole, an ilm peel is the surgery required to fix the problem. The ilm doesn't peel by itself, it's only done as part of a surgery.
A retinal procedure. The ilm is a layer of the retina that can sometimes get wrinkled. When you peel the retina it flatens the retina and can sometimes improve vision.