Fluctuation of AC depth occurs frequently in soft pediatric eyes. Techniques mentioned to avoid iris prolapse (tight fit wounds) also help to maintain a stable and deep AC. Bimanual irrigation/aspiration approaches help to avoid AC fluctuation. Some surgeons prefer to use an AC maintainer rather than holding both instruments as in bimanual surgery. An unstable AC usually results from too much leak around the instruments that are placed in the AC. Venturi pump machines often have a fluid pump that can be increased to offset the leak. Gravity-fed irrigation systems are not as effective. The surgeon must also learn to balance the aspiration with the irrigation in a way that does not repeatedly shallow the AC during surgery. Repeated shallowing or flattening and then deepening of the chamber during surgery acts like extensive iris manipulation. It releases inflammatory mediators and results in a marked increase in postoperative inflammation as well as intraoperative miosis.

It is no longer a secret that anterior capsulectomy is notoriously difficult in infants and young children because of the extreme elasticity of the anterior capsule, scleral collapse causing positive vitreous pressure, and, at times, poor dilatation of the pupil. Rarely, an anterior capsule tear may be observed as soon as the AC is opened, caused by the sharp tip of the entrance knife, especially when the AC is very shallow. The availability of better operating microscopes and microsurgical instruments combined with higher-viscosity OVDs are helpful; however, “runaway rhexis” or tear extending out toward the equator is still frequently encountered (Fig. 49.4). For manual continuous curvilinear capsulorhexis (CCC), it occurs mainly during anterior capsulectomy. Once a manual CCC is achieved, the edge is very strong and will withstand intraocular gymnastics very efficiently. When a tear occurs during manual CCC, the surgeon should stop tearing, place more OVD, regrasp close to the tear edge, and pull toward the center of the pupil. If this does not recover the capsulectomy easily, conversion to a vitrectorhexis or to a Kloti diathermy capsulectomy has been successful for us. For vitrectorhexis and Kloti diathermy, a tear is more likely to occur during IOL implantation or irrigation/aspiration or after OVD removal. Care should be taken to avoid right-angled edges, which is a weak point and likely to tear during intraoperative maneuvering. If a right-angled edge is seen during the capsulectomy, it should be rounded out using the vitrector before completion of the capsulectomy. The sudden flat AC that can occur after the OVD is removed before the wounds are sutured can cause the IOL to move anteriorly and place stress on the capsulectomy edge. Every effort should be made to sew the wounds prior to complete removal of the OVD if possible. A temporary air bubble can be used at the end of the procedure as another way to avoid shallowing of the chamber as the wound suture is being tied. Chapter 17 describes studies reporting the intraoperative tear rate using different techniques and other specific issues related to anterior capsule management.

Inappropriate size and shape are also complications of the anterior capsulectomy that are seen more often with children than with adults. Surgeons are urged to go slow and pay particular attention to size, shape, and centration each time the capsulectomy edge is released. If the capsulectomy opening is too small, it can be enlarged after the IOL is inserted. If it is too large or poorly shaped, take care to get the haptics of the IOL under the capsulorhexis edge and place the haptics where the capsulectomy edges can be most easily seen. Every attempt should be made to cover the edge of the IOL optic with the capsulorhexis edge when possible.

A high intraoperative vitreous pressure is produced as a result of scleral collapse due to low scleral rigidity, which results in forward movements of the iris-lens diaphragm. In pediatric eyes, the posterior capsule is often convex rather than concave from the surgeon’s viewpoint. We often remove the peripheral lens cortex first, leaving the central nucleus of the lens until last since it holds the posterior capsule back in a more flat or concave configuration. Use of a high-viscosity OVD (e.g., Healon GV) helps to maintain a deep AC and keep the iris-lens diaphragm back.

A posterior capsule tear is not as devastating to a pediatric cataract surgeon as it is to an adult cataract surgeon, because pediatric cataract removal often includes posterior capsulectomy and vitrectomy. However, an uncontrolled posterior capsule tear may still compromise the ability of the surgeon to safely place an IOL into the capsule. Posterior capsule tears may occur due to preexisting posterior capsule defects (Fig. 49.5). The surgeon can recognize a torn posterior capsule during lens aspiration by signs such as a sudden deepening of the AC. This occurs instantaneously as a rent appears in the capsule. As this occurs, the pupil will dilate in response to the deepening AC. Finally, during aspiration, lenticular particles/residual cortical matter falls away from, and will not come toward, the tip of the aspirator. This occurs because the tear in the posterior capsule alters the flow dynamics in the AC. Sometimes the presence of vitreous in the AC may also indicate a torn posterior capsule. The posterior capsule can tear during hydrodissection, irrigation and aspiration, capsular polishing, lens insertion, and OVD removal. Posterior capsule tear can also occur during incision enlargement with the sharp tip of the keratome.

In all cases, if the posterior capsular tear is entirely within view, a posterior capsulorhexis can be attempted. If the vitreous face is intact, this is done by placing OVD above and below the tear, pushing the vitreous face back, and allowing room to grasp the torn capsule. If the vitreous face is already broken, OVD is necessary only to stabilize the AC and make room for the forceps. Using a capsulorhexis forceps, the capsule is then gently torn to create a 360-degree posterior capsulorhexis. Failed attempts may result in extension of the tear and, if not already present, vitreous loss.

Alternatively, the vitrector handpiece can be used to round out the posterior capsule tear, remove residual cortex, and remove prolapsed vitreous. Pediatric surgeons are more likely to use this approach since the use of the vitrector is often more familiar than the use of a capsulorhexis forceps on the posterior capsule. Care should be taken to begin with a low flow so that the AC dynamics are not changed drastically when the instruments are placed in the eye. This could lead to an extension of the posterior capsule tear. Once rounded out, the posterior vitrectorhexis can be quite stable and resistant to further tearing. The advantage of the vitrector handpiece is that it can safely remove cortex when it is mixed with vitreous. It can also cut the capsule and vitreous simultaneously without undue traction of the vitreous base or retina. A Venturi pump-driven vitrector handpiece works best when used in this way.

Anterior vitreous face (AVF) disturbance during posterior capsule rupture is well recognized in adult cataract surgery. However, in children, this is less of a problem because anterior vitrectomy has become an integral part of the surgical strategy. However, some surgeons prefer to err on the conservative side and avoid anterior vitrectomy in children 2 to 8 years of age. When performing a posterior continuous curvilinear capsulorhexis (PCCC) without vitrectomy, surgeons should watch for signs for AVF disturbance, and if seen, a vitrectomy should be performed. The subtle signs are a vitreous strand in the AC, vitreous strands attached to the capsule flap, and distortion of the anterior and posterior capsulorhexis. The later is considered a pathognomonic sign of AVF disturbance.⁶ Signs of an intact AVF include its bulging structure and its characteristic triamcinolone staining patterns recently documented by Sudhalkar et al.⁷ These include the homogenous staining pattern of three buttonholes, giving the impression of a tabletop configuration with three subramifications.

Vitreous strands can remain in the AC. When this occurs, it should be removed using vitrector. A second instrument may be needed, through a paracentesis, to sweep the
vitreous strand away from the wound so that the vitrector handpiece can remove it. A taut strand of vitreous will not easily enter the vitreous cutter until its connection to the wound is broken. A pars plana approach to the anterior vitrectomy avoids this possible complication. Some surgeons use triamcinolone to identify any residual vitreous, while some choose to use miotics to look for peaking of the pupil.

Intraoperative hyphema may occur and may or may not need to be cleared before wound closure.⁸ A small hyphema will clear spontaneously. Hyphema was noted in approximately 5% of eyes in the IATS.¹ Vascularized plaques (Fig. 49.6) or patent hyaloid artery remnants may lead to intraoperative vitreous hemorrhage.

Laceration of the equator of the capsular bag with the microvitreoretinal (MVR) blade is a possible complication of a pars plana incision. The entry with the MVR blade should be aimed toward the center of the vitreous cavity to avoid hitting the capsular bag. The capsule may still be distended with an OVD or irrigation fluid. Surgeons like to see the tip of the MVR blade in the pupillary space through the operating microscope before withdrawing it. The tendency is to advance the MVR blade too anteriorly. In very young infants, the entry is even closer to the limbus. In these cases, the MVR blade must be aimed at the optic nerve to avoid hitting the capsular bag. Another less commonly encountered complication is bleeding into the vitreous cavity. The vitrector cutter must be turned off before the handpiece is withdrawn. If not, the cutter may engage the tip on a ciliary process during handpiece withdrawal, causing profuse bleeding. If this occurs, intraocular cautery will likely not be needed but a full core vitrectomy will be needed to clear the blood. A retinal specialist will need to be consulted unless the surgeon is experienced in core vitrectomy techniques.

It should be noted that zonular dialysis greatly increases the risk of both vitreous loss and lenticular material sinking into the vitreous. Obviously, IOL implantation may be more difficult. The surgeon needs to evaluate the number of clock hours involved with the zonular dialysis and the surgeon’s ability to perform lens aspiration in this setting. When inserted into the capsular sac, an endocapsular ring provides a circumferential expansile force to the capsular equator. However, the endocapsular ring does not always stabilize the lens position and often entraps the lens cortex between itself and the lens capsule. Removal of the trapped cortex can be difficult, and in fact, attempts to do so can cause further zonule dehiscence. Nonetheless, expansion of the capsular sac is often desirable either during or after lens removal, and these devices enhance implant centration and reduce postoperative pseudophakodonesis. Intracapsular rings (e.g., Cionni ring and capsular tension ring segments) are available and are used frequently in adult cataract surgery.

The relatively short length of the iris retractor hook and the single-plane design may cause them to slip off the capsule easily during manipulation of the nucleus. In addition, short iris retractors do not extend into the capsular fornix and, therefore, do not offer support to this region. Because of some of these disadvantages, Mackool designed capsule retraction devices specifically shaped for the purpose of retracting the anterior capsule. According to experience during adult cataract surgery, multiple retractors can be placed at 45-degree intervals to provide reliable support to the capsule and the enclosed lens. The elongated return of the retractor extends into the capsular fornix and therefore functions to prevent attraction of the equatorial capsule to the tip of the aspiration handpiece. After lenticular material removal is complete, an endocapsular ring (standard or Cionni design) can be inserted prior to removal of the retractors and insertion of an IOL.

Visual axis opacification (VAO) has been discussed elsewhere in this book. PCO or VAO is most common complication after cataract surgery in children (Figs. 49.8, 49.9, 49.10, 49.11, 49.12, 49.13, 49.14, 49.15). It is important to note that VAO may occur as closure of a posterior capsule opening, PCO in eyes with intact posterior capsule, lens reproliferation into the visual axis, pupillary membrane, reticular fibrosis of the AVF, or corneal edema/opacity. VAO may occur anytime after cataract surgery. For example, a case of soft lens matter recurrence causing VAO 17 years after the
surgical removal of congenital cataract was reported.¹⁰ As discussed throughout the book, primary posterior capsulectomy and vitrectomy are considered essential steps to prevent VAO in the management of pediatric cataract. Researchers are working on other options to prevent this complication (e.g., sealed capsule irrigation, see Chapter 50) (Fig. 49.16).

Glaucoma can occur during the early or late postoperative period. Although open-angle glaucoma is more common, angle-closure glaucoma is rarely observed (Fig. 49.17) (see Chapter 51).

Toxic anterior segment syndrome (TASS) is a rare inflammatory condition usually observed within the first 2 days after anterior segment surgery.¹¹

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