Guo C, et al. - The outcome of delay of surgery and preoperative speed of progression (SP) underwent investigative analysis, on the surgical outcomes in primary congenital glaucoma (PCG) patients. A correlation was brought to light between lower preoperative SP index (SPI) with better short-term IOP control and success rate, in PCG patients. The analysis of preoperative SPI could assist with the surgical decision. Early detection and treatment were significant due to the same SPI.