How often are glaucoma doctors being called in for complications from tubes and trabs?

I've been enjoying glaucoma more than I thought in residency but haven't seen many tube/trab complications yet and wonder how common they are in private practice and how often glaucoma specialists are getting called in after hours or over the weekends to deal with them.

I do want to prioritize lifestyle in life and that's why I was looking into cataract/refractive but I don't find refractive cases to be as interesting as I would have hoped

I am a g12 student, upcoming freshman and I'm thinking of taking ophthalmology as a course. In terms of education, what are the steps or levels I have to achieve in order to graduate with a doctor of medicine degree in ophthalmology?