This paper reports an iterative design project of a network control system to support ophthalmologic examination, for use in support of telemedicine. The project is a case study of development and deployment of a telemedicine system through human-centered design approaches. At the early stage of design, we carried out field research and paper prototyping on the network control system with ophthalmologists. Then, we developed working prototypes for conducting usability tests and field tests. We examine lessons learned from the design process and the designed product.