Glaucoma can be a manifestation of a patient’s diabetes and the situation you describe would be coded as E11.39 and H42. (Remember that absent a specified diabetes type, the default is Type 2.) Although a lot of diabetics also have glaucoma, its connection to DM is extremely rare and generally established by the ophthalmologist. If your office has many patients whose glaucoma has been linked to diabetes, we suggest that you obtain a specialist’s confirmation for your records.