Congenital microphthalmia is a developmental abnormal genetic disease with a prevalence of 0.008%~0.032% according to foreign epidemiological survey data. Microphthalmia is only 2/3 of the size of a normal eye, with an eye axis length of ≤20.5mm. It is usually combined with a variety of ocular developmental abnormalities, such as congenital cataract, closed-angle glaucoma, and uveal leakage. Congenital cataracts that are combined with small eyes are mostly nuclear, difficult to dilate, and very difficult to treat surgically, which can lead to permanent amblyopia or blindness without surgery. Due to the special anatomical structure of patients with small eyes, postoperative complications such as malignant glaucoma, eruptive choroidal hemorrhage, and retinal detachment often lead to surgical failure. If ultrasound emulsification technique is applied, due to the small surgical incision, good intraocular confinement can be maintained intraoperatively, which can avoid drastic changes in intraocular pressure and thus can effectively prevent the occurrence of complications. In addition, due to the short axis of the small eye and the high hyperopia, there is a large error in the calculation of the IOL degree, and the conventional lens degree cannot meet the implantation needs, so in 1993, Gayton innovatively implanted two posterior chamber IOLs (combined degree +46D) into the small eye at the same time, which is the earliest Piggyback technique, bringing a corrective effect to the majority of patients with short axis. This is the earliest Piggyback technique, which brings hope for correction to patients with short eye axis. Good preoperative communication between the doctor and patient is necessary to gain the understanding of the parents, and the doctor and patient should work together to share the risk, give reasonable surgical treatment, and provide active amblyopia training after surgery to maximize the visual function of the child, hoping that the child with small eyes can have a bright world!