3. Any professional activities contemplated in section 4 may only be performed in an ophtalmologist’s office or on behalf of an institution which operates a hospital centre within the meaning of the Act respecting health services and social services (chapter S-4.2) or the Act respecting health services and social services for Cree Native persons (chapter S-5). The patient must have an ophtalmological examination as a result of which he or she is referred to an orthoptist, except for the professional activities contemplated in the first to the sixth paragraphs of that section which may also be performed in the course of a screening program.