光 - 也称为一个operating lightor外科灯头– is a医疗装置旨在帮助医务人员surgical procedure通过照亮局部区域或腔patient。几种手术灯的组合通常被称为“手术光系统”。

In the mid-1850s,手术室在天花板上的窗户朝向东南部建造，可以尽可能地受益于自然阳光。最大的问题是照明的依赖性以及是否程序could be done on the time of day and weather conditions. Furthermore, a doctor, nurse or medical equipment easily blocked the light. The use of mirrors on the four corners of the ceiling to reflect sunlight towards the operating table only slightly alleviated these problems.

尝试使用光学冷凝器in an indirect light to reduce the加热，但没有成功。入口电灯在1880年代的手术室里伴随着问题。随着早期电气技术控制发出的光很差。电光仍在移动和弥漫，很棒热辐射。

发光二极管随着光源消除了热辐射的问题并降低了能量要求。

The distance between the points of 20% illumination intensity above and below the center point. From the point of maximum illumination, which is the center of the light field 1 meter from the light-emitting surface, the photometer is moved toward the light until the light intensity measured falls to 20% of the maximum value. The distance between the center and this point is defined as L1. The similarly measured distance in the direction away from the light is L2. The depth of illumination without needing to refocus is the sum of the two distances L1 and L2. In the second edition of the IEC standard, published in 2009, the threshold value was revised from 20% to 60%