The product has 22mm inter-optical path distances. As a general rule, the longer the distance between the two optical paths, the better the stereoscopic view, but the narrower the binocular field of view in fundus examination. In reverse, the shorter the distance between the optical paths, the poorer the stereoscopic view, but the wider the binocular field of view in fundus examination. With this in mind, we have achieved optics suitable for fundus examination by choosing the optimal 22mm as the inter-optical path distance. It has converging binocular tubes. The binocular tubes with a 6-degree convergence provide easy binocular fusion, ensuring stress-free observation. Advanced multi-coating is applied to all lenses used in the microscope for excellent optical performance. As a result bright images free from flare and ghost are obtained, improving the quality of examination and treatment. With the 5-step drum magnification changer (3-step for the SM-2N) that offers a wide range, from low to high, the optimal magnification is obtainable in clinical use. Also with the smoothly-rotating knob, this magnification mechanism provides a stress-free environment.