The images in each eyepiece of the ophthalmic operating microscope should be identical. Among them, it is mainly a binocular solid microscope, and the coincidence of the images seen by the two eyes of the operator is better. Detection method: Use any one of a pair of eyepieces in the microscope, adjust its diopter to 0, and observe with one eye. On the position of the object, put a piece of white paper marked with a "cross line", and make the "cross line" clear after adjustment. Move the white paper to place the intersection of the "crosshairs" in the eyepiece field of view. Draw 4 lines at the 4 junctions between the "cross line" and the edge of the field of view, and then observe that the other eyepiece should be in the same position. When both eyes are observed at the same time, they should be completely coincident.
 
There are two types of illumination for ophthalmic surgical microscopes:
 
①Internal light source - the light source is combined in the microscope, and the irradiation direction is coaxial with the microscope, which is suitable for the illumination of deep tissue.
 
②External light source - the light source is located outside the microscope, and it is divided into two types: coaxial and non-axial illumination systems. In order to make the object surface have sufficient illumination, most of the light sources are halogen lamps or optical fibers are introduced into the microscope, and are directed to the surgical field through the objective lens. Some surgical microscopes have both internal and external illumination systems, as well as illumination systems with slit lamp microscopes. High-quality ophthalmic surgical microscopes have a fully coaxial light source.
 
The ophthalmic operating microscope requires that the shallower or deeper parts can be clearly observed during the operation, and the three-dimensional sense is strong. Operates with a small range of shades and does not need to adjust the focus. Therefore, there should be a certain range of depth of field requirements for the operating microscope. The primary mirror is at 45° to the microscope body, while the assistant mirror is at 30° to the microscope body. When adjusting the focal length of the microscope, the field of view of the eyepiece should be clear.