University teachers can publish academic papers after retirement, because academic papers do not have to be published while teachers are in office. You can publish them after leaving your job. As long as you have this ability and level, it is entirely possible. Academic papers published by teachers are also a summary of knowledge and clarification of opinions. So no matter whether you are in education or medical field, as long as you are competent, knowledgeable and able to express your opinions, such papers can be published at any time.