In the first half of the twentieth century, the procedure of linear cataract extraction was proposed based on surgical principles of discission. During the surgery, pressure was exerted on the surface of the cornea with a surgical device after cataract discission. In the meantime, irrigation was performed to flush out lens materials from the anterior chamber through the corneal or scleral incision [4]. This surgical technique had undergone many modifications. The removal of lens substance with irrigation was sometimes performed at the same time as the discission/needling procedure (one-stage procedure) or after about a week later (two-stage procedure). Compared with discission/needling alone, linear cataract extraction was associated with lower incidences of postoperative inflammatory reaction, secondary membranes, and secondary glaucoma. However, most pediatric patients still ended up blind, and this technique was also abandoned.

In the early 1960s, cataract aspiration, a more effective approach to removing the lens material than anterior chamber irrigation, was adopted and continually modified by pediatric ophthalmologists [5]. This technique involved an anterior capsulotomy approximately 2 mm in diameter and aspiration of the lens material with a syringe through the capsulotomy, leaving most of the lens capsule intact. Limitations of cataract aspiration were as follows: (1) The cortex removal was usually incomplete; (2) the collapsed capsular bag and fibrous adhesion of anterior and posterior capsule provided a scaffold for lens fiber regeneration, often resulting in a thick secondary membrane. Although the procedure of cataract aspiration alone is no longer employed, it did lay the foundation for cataract irrigation and aspiration.

As the surgical approaches that preserve the lens capsule would inevitably lead to secondary opacification of the posterior capsule, intracapsular cataract extraction, previously performed only in adults, was also conducted in pediatric patients. However, because the zonule of pediatric patients was resilient and the surgery gave rise to multiple complications, this surgical approach did not find acceptance among pediatric ophthalmologists [5].

Restoring transparency of the visual axis was the principal purpose of pediatric cataract surgery. In the mid-1960s, a double-barreled cannula was introduced, which was a critical breakthrough in the development of cataract extraction. The dual irrigation and aspiration technique, especially after the introduction of phacoemulsification, enabled the ophthalmologists to maintain the anterior chamber depth during cataract aspiration, which made the removal of the lens material safer, more complete, and more effective. At present, cataract irrigation and aspiration are among the most favored surgical techniques for pediatric cataract extraction.

In the 1970s, the automated vitrector (Fig. 7.5a) was introduced into pediatric cataract surgery. The thick and gummy lens material found in children is more easily and efficiently aspired using this instrument as opposed to using a double-barreled cannula. Moreover, posterior capsulotomy and anterior vitrectomy (Fig. 7.5b) could also be performed at the same time, which lower the incidence of reopacification of the visual axis to some extent [6]. There are two approaches for LAV. One is through the pars plana, and it is a more efficient approach in removing the lens material. Since the operation is performed in the posterior chamber and the vitreous, it is associated with lower risks for endothelial loss of the iris and cornea. The other approach is through the limbus, and it is a more familiar surgical technique for anterior segment surgeons despite its lack of advantages compared to the pars plana approach. Apart from cataract irrigation and aspiration, LAV is another surgical technique that is still in use for pediatric cataract extraction.

In the 1970s, phacoemulsification was used in pediatric surgery for the first time [7]. Since a hard nucleus is seldom found in pediatric patients, the lens material can be eliminated merely by aspiration in most cases. If any hard material is encountered, ultrasound is available to help remove it. Moreover, the larger aspiration port of the phacoemulsification handpiece is more efficient than that of the irrigation/aspiration handpiece in aspirating the lens material. Phacoemulsification has become one of the routine options for pediatric cataract surgery due to its high efficiency and safety (Fig. 7.6).

For pediatric patients with cataract, clearing the visual axis is just the beginning for restoring visual function, and the postoperative correction of refractive errors of the aphakic eyes is equally important. Intraocular lens (IOL) implantation is an ideal approach for aphakic correction in pediatric patients, and the details of the implantation will be elaborated in Chap. 15 (Fig. 7.7).

To sum up, throughout the evolutionary history of pediatric cataract surgery, we have come to know more about the anatomy and physiological characteristics of pediatric eyes, the development of the eye and vision, and the mechanisms for the occurrence of surgical complications. Meanwhile, the surgical instruments and techniques have also improved. Now, pediatric cataract surgery is safer, less invasive, and associated with fewer complications than before.

In the 1960s, Chandler and some researchers found that the surgery for many pediatric patients with congenital cataract usually resulted in poorer visual acuity or even vision loss. Therefore, they proposed that cataract surgery should not be recommended unless preoperative vision was extremely poor [8, 9]. With the development of medical technology, a consensus has been reached among ophthalmologists that the surgical treatment for pediatric cataracts that greatly hinder the development of visual function should be conducted as soon as possible to clear the visual axis and restore visual function [10–12]. In children with cataracts that are not dense (e.g., lamellar cataract) or not on the visual axis, follow-up observations are advisable since it preserves accommodation and a series of problems like secondary opacification can be avoided. In children with unilateral cataract, anisometropia should also be taken into consideration apart from accommodation; therefore, the treatment should tend to be more conservative. Moreover, for premature infants and children with systemic dysplasia or disorders, general anesthesia poses a high risk. In these patients, systemic abnormalities should be treated before the elective cataract surgery.