Abstract
This paper discusses a characteristic of stereoscopic ophthalmological surgery images including ROI (Region of Interest). These images including ROI are divided into the ROI region of high resolution, and the non-ROI region of low resolution. When doctors supporting the surgery observe these images, an unnatural depth is perceived between two regions, and an appropriate medical support may be obstructed. The result of the subjective evaluation experiment using the random dot stereogram on the relation between the perceived depth and the degradation of a non-ROI region is shown.