中国画理论中有“远人无目”、“远山无树”、“远水无波”之说。这是把人眼视物的现象运用到绘画中:远距离的东西,人眼无法看清,故没有细节。其实,这只说到问题的一半。依我对视觉焦点的理解,另外一种视觉现象也是存在,即“近人无目”。因为固然远景不能在眼中形成清晰影像,是距离太远视觉焦点不能达到,可是近景虽然在视觉焦点可达范围,却若不是焦点所在,也不能在眼中形成清晰影像。一方面,从人眼生理功能看,“远人无目”是毋庸置疑的;另一方面,从视觉焦点规律看,“近人无目”也是可能的。从根本上说,某样东西清楚与否,取决于视觉焦点所在与否。焦点所及则清楚,,反之则模糊。我曾经觉得当我双眼看去,能同时看清一片范围包括一定宽度和深度。其实并非这样,我们眼的视觉焦点是一个点,而不是一块面或 Chinese painting theory has “no man in the distance”, “distant mountains without tree”, “no water away from waves,” said. This is the use of the phenomenon of the human eye as a visualization: long-distance things, the human eye can not see, so there is no detail. In fact, this only speaks of half of the problem. According to my understanding of the visual focus, there is also another visual phenomenon, that is, “no one in sight”. Although the vision can not form a clear image in the eye, it is too far from the visual focus can not be achieved, but close range although the focus of the visual range, but if it is not the focus, it can not form a clear image in the eyes. On the one hand, from the physiological function of the human eye, there is no doubt that “distant people without eyes” are indisputable; on the other hand, from the point of view of visual focus, it is also possible that “near humanlessness” is possible. Fundamentally, whether something is clear or not depends on where the visual focus is. The focus is clear, and vice versa. I used to think that when I looked in my eyes, I could at the same time see a range including a certain width and depth. In fact, this is not the case, the visual focus of our eyes is a point, not a face or