The application of machine learning in technical fields is developing in an increasingly large way. It offers significant benefits with notable results. In the field of diagnosis, machine learning is also widely used. Many studies have been proposed and successfully implemented. Recently, the iris has been used as a major instrument in personal identification. In the identification direction, numerous successful studies on the application of iris recognition have been commercialized for both civilian and military purposes. In addition, the iris also reflects the health status of the body, so many studies on the application of iris images in disease diagnosis have also been introduced. In this study, we examine recent results up to 2025 on the application of machine learning on iris images in disease diagnosis to provide a basic, multi-dimensional perspective. And we also discuss the challenges, opportunities, and potentials we are leveraging from this approach.