Complex sentence: Established in 1989, the Opticians Association of Canada is a national organization includes all provincial Opticianry Associations in Canada and looks after the various interests of opticians on a national basis.
Split into simpler sentences: Established in 1989, the Opticians Association of Canada is a national organization whose membership is comprised of all provincial Opticianry Associations in Canada. The role of the OAC is to advocate for the various interests of opticians on a national basis.