Every ophthalmologist knows his individual interpupillary distance (PD) and adjusts it lat­erally on the eyepieces so that a comfortable, edge-free, and double-image-free view is possi­ble in the surgical image. Usually, the adjustment range is between 55 and 85 mm. Additionally, both eyepieces can be adjusted separately with a fine scale in the plus and minus range. If there is “instrument myopia,” the surgeon will notice that the image on the monitor is not always sharp when focused by the surgeon in the operating area. In this case, it is necessary to gradually turn the eyepieces towards the minus direction and refocus until a sharp image is achieved for both the surgeon and on the monitor. It is also impor­tant to know from which optical path (right or left) the camera derives the image. If surgery is to be performed without glasses, the corresponding refraction must be taken into account. The adjust­ment range is usually between −5 and +8 diop­ters. Some microscopes are also equipped with variable eyecups made of rubber or hard plastic, ensuring an optimal distance from the eye or glasses while limiting the amount of light enter­ing from the side. In principle, one should be familiar with the working distance of the micro­scope, which is between 175 and 200 mm.