Recently, there has been much progress in wearable computing. Input/output interface and security are important research areas in wearable computing. In this paper, we describe considerations which should be taken into account in designing a wearable interface and iris recognition system. One of the most important issues in designing a wearable iris recognition system is the radial lens distortion. We suggest a radial distortion elimination method which is simple but accurate. Experimental results show that the quality of the image captured by our system is good enough for iris recognition and we can achieve 0.18% of the EER by applying our proposed radial distortion elimination method.