Nasolacrimal duct blockage surgery for adults, which doctor ENT or eye surgeon?

NLD blockage. Usually ENT, some oculoplastic surgeons.
Opthalmologist first. I would first contact your ophthalmologist if you have one. If you have an otolaryngologist with whom you are familiar, i would ask their advice as well. This should be a straightforward evaluation. Surgery can be extensive depending on the findings of the evaluation.