Capsule radial tear, or “runaway rhexis,” is a major complication encountered in pediatric cataract surgery. A radial tear of the anterior capsule may severely affect all the subsequent procedures and destroy the integrity of the capsule, which may contribute to the development of posterior capsule rupture, vitreous prolapse, and IOL dislocation.

Capsule tear often occurs when the capsulorhexis opening is too large and the surgeon fails to reverse the capsular flap in time, resulting in a “runaway rhexis” that tears out to the lens equator. Fortunately, an anterior capsule tear in pediatric patients rarely extends to the posterior capsule, and a continuous capsulorhexis can still be achieved if handled timely and properly. When an anterior capsule tear occurs, the surgeon should stop capsulorhexis immediately and check the extent of the tear. If the tear is small and has not extended to the equator, the surgeon may fill the chamber with OVD, flip the capsular flap, and pull the capsular toward the center of the pupil, which has always been successful in clinical practice. Alternatively, the surgeon may place more OVD, open the capsule opposite to the tear with capsulotomy scissors, and restart capsulorhexis in the reverse direction, after which two tears meet to form the CCC (Fig. 22.2). Besides, the technique of can-opener capsulotomy may also be used around the site of the tear to reduce tension on the anterior capsule, which may help to prevent further extension of the tear. Some researchers also recommend conversion to a radiofrequency diathermy capsulotomy when the surgeon feels uncertain about controlling the tear [2].

In order to prevent capsulorhexis-related complications and complete an intact CCC, the surgeon should use adequate high molecular weight OVD to maintain space, aim for a slightly smaller-than-desired capsulotomy, reverse the capsular flap and always pull the flap toward the center of the pupil, and also frequently adjust the grasp location or where the capsulorhexis needle engages the capsule. The capsulotomy edge generated by a radiofrequency diathermy device is not smooth, which may be associated with a higher incidence of secondary tear in subsequent procedures.

A small capsulorhexis opening poses additional operative difficulties in pediatric cataract surgery, especially for cortex removal beneath the incision. It would even cause complications such as radial tear of the capsulotomy and posterior capsule rupture.

Postoperative contraction of the small opening may affect the centration and stability of the IOL and increase the risk of capsule contraction syndrome or capsular block syndrome. But as the lens cortex in pediatric eyes is soft and easy to aspirate, a relatively small opening does not affect surgical maneuvers. When the capsulorhexis opening is found to be too small and/or poorly shaped during the surgery, a second capsulorhexis may be performed before or after removal of the lens material (Figs. 22.3, 22.4, and 22.5). If the opening is so large that the edge of capsulotomy fails to cover the edge of the IOL optic, decentration or tilting of the IOL may occur, as well as an increased risk of posterior capsule opacification (PCO). Injury to the zonular fibers and posterior capsule and radial tear of the anterior capsulotomy may also be induced.