Abstract: 【Abstract】With the continuous development of refractive surgeries, measurement of scotopic pupil diameter becomes increasingly important. This article aims to introduce three methods of scotopic pupil diameter measurement: the traditional pupil diameter measurement tools, pupil measurement functions built in the anterior segment detectors, and infrared  method. The traditional pupil diameter measurement tools are inexpensive and simple to operate, but there are many deficiencies in scotopic situation. Pupil measurement functions built in the anterior segment detectors are domestic mainstream methods, the accuracy and repeatability of that are between the traditional method and infrared  method. Infrared measurement is the most reliable and widely used in foreign research and clinic, but seldom used in the domestic because of its high price. (Int Rev Ophthalmol, 2012, 36: 314317)