The implantable collamer lens(ICL)is a widely popular option for the correction of refractive errors. ICL implantation brings a whole new dimension to the vision, from the anterior chamber phakic ICL to the posterior and central hole ICL. Even though there are fewer reported complications, ICL size selection remains challenging due to the differences in device measurements and ICL sizing formulas. With the widening comprehensiveness of ICL implantation and the ongoing development of ophthalmic devices and technologies, particularly the advent of artificial intelligence, more and more indicators such as sulcus-to-sulcus(STS), crystalline lens rise(CLR), angle-to-angle(ATA), the iris pigment end to the iris pigment end(PTP), anterior chamber width(ACW), and anterior chamber angle(ACA)are providing references in the selection of ICL size, this article provides a review of ICL size selection.