observation by naked eye肉眼观察
identifying by naked eye肉眼鉴别
by the eye以目估计
hint by the eye用眼示意
observed by naked eye肉眼观
counting by naked eye目视计数法
by Midnight Eye大友克洋
Start By Making Eye Contact以进行眼神交流开始
visible material by bare eye肉眼可见物