JCAHPO's three core levels of certification offer a progressive career ladder for ophthalmic medical personnel who seek growth in their profession. Certified Ophthalmic Assistant (COA) is the Entry Level certification. Each level of core certification has prerequisite eligibility requirements and an examination process. OMP may progress from one level of certification to the next. Formal training or work experience and examination can also serve as an entry point to certification at any level of the core levels.