M. Edward Wilson Jr., MD, and Suresh K. Pandey, MD Charleston, S.C.

Edited by Harold P. Koller, MD

Cataract surgery in children remains complex and challenging. Achieving a consistently good visual outcome from the treatment of childhood cataracts continues to be difficult even for the most talented and diligent ophthalmologist.¹
 A major reason for inconsistent visual outcomes is that, unlike the treatment of adult cataracts, the timing of cataract surgery in children is paramount. In a young child, a cataract does not merely blur the image received by the retina; it also disrupts the development of the visual pathways in the central nervous system.²
 For this reason, we cannot view cataract surgery in young children purely as a technical problem and an end in itself. Rather, it is an integrated component of the treatment of amblyopia.³


This article will outline the management options for pediatric cataracts and touch on many of the surgical considerations unique to the treatment of these young patients.

Background
Cataract remains one of the most important causes of blindness in children and represents the major preventable cause of lifelong visual handicap. According to a World Health Organization estimate, a child is born blind or acquires

Figure 1a. External photograph of the anterior segment showing a congenital fetal nuclear cataract.

All images: M. Edward Wilson Jr., MD

blindness every minute of the day, with most cases of blindness occurring in developing nations (See Figures 1a, b).

Approximately 45 percent of congenital cataracts are unilateral, and the rest are bilateral. The total incidence of cataracts in childhood is several times greater, however, due to the effects of trauma, metabolic disorders, radiation treatment and the need for corticosteroid medications in some children. Additionally, a seemingly expanding number of families manifest autosomal dominant transmission of acquired lamellar cataracts, which most frequently occur in the toddler and pre-school years.

The surgical management of cataracts in children is markedly different than in adults. The eyes are not only smaller because of age, but many are also microphthalmic. Decreased scleral rigidity and increased vitreous upthrust make surgical manipulations within these eyes more difficult. In addition, the anterior chamber is often unstable, the capsule management requires special considerations, and the propensity for postoperative inflammation is higher than in adults. Ocular growth, meanwhile, makes the selection of an intraocular lens power difficult.

Timing and Indications for Surgery
The timing of surgery is crucial. Researchers have demonstrated that the critical period for the surgical treatment of dense, unilateral congenital cataracts is from birth to age 6 weeks.⁴
 While they found no prognostic advantage when surgery was performed prior to 6 weeks, after this age the chances for good visual acuity (better than 20/80) decrease. When bilateral dense congenital cataracts are present, permanent sensory nystagmus occurs when surgery is delayed beyond 3 to 4 months of age. Partial cataracts and cataracts acquired after infancy present a greater dilemma as to the proper timing for surgery (See “Management of Pediatric Traumatic Cataracts” on p. 99).

When a child beyond infancy presents with dense, central opacity of uncertain duration and Snellen visual acuity cannot be accurately measured, surgery is indicated within a few weeks of detection. Partial cataracts, by contrast, are sometimes managed initially with non-surgical methods. A trial of patching may be indicated if the level of visual loss seems disproportionate to the density and size of the cataract. Pharmacologic dilation of the pupil can occasionally be helpful as an adjunctive or temporizing treatment.

The surgical removal of a partial or moderately dense cataract in a literate child is usually indicated when the cataract reduces the Snellen visual acuity to 20/50 or 20/60. This is a case-by-case decision, however, based on the documented progression of the cataract and on the child’s visual functioning, visual needs and expected best visual outcome.

Surgical Techniques
This section will provide a brief overview of the management options for childhood cataract, including our preferred technique.^5-7

 • Anesthetic technique. Young children require general anesthesia. If the level of anesthesia changes to a lighter plane during the surgery, the Bell’s phenomenon will become active. For this reason, we recommend a 4-0 silk traction suture beneath the superior rectus muscle. 

 • Wound construction. Wound configurations that are self-sealing in adults will often leak when used in children, because they have thinner and less rigid sclera. Even the corneal tissue is less likely to self-seal in children. Moreover, pediatric patients tend to traumatize their eyes more often than adults do in the early postoperative period. Synthetic absorbable 10-0 sutures help address this problem. Implanting a rigid IOL usually involves a scleral tunnel wound, while, for foldable IOL insertion, either a corneal tunnel or a scleral tunnel may be used. 

 • Viscoelastic substances. Viscoelastics are now often referred to as ophthalmic viscosurgical agents, since their intended surgical role is viscosurgery.⁸
 A visco-adaptive, such as Healon5 (Pharmacia Corp.), or a super viscous ophthalmic viscosurgical agent like Pharmacia’s Healon GV best facilitates the

Figure 1b. Slit-lamp photograph of the anterior segment showing total traumatic cataract secondary to blunt trauma. Note the self-sealed corneal laceration (arrow) and ruptured anterior lens capsule, with presence of flocculent lens material in the anterior chamber.

difficult intraocular manipulations that must be performed during pediatric cataract surgery. These agents are cohesive and help maintain anterior chamber stability, while helping to offset the low scleral rigidity and increased vitreous upthrust found in pediatric eyes. 
 
• Anterior capsule management. The anterior capsule is highly elastic in children and poses challenges in the creation of the capsulotomy. While a manual continuous curvilinear capsulorhexis is ideal for adults, it is more difficult to perform in young eyes. Here are some technical tips drawn from our experience for performing a manual CCC in a child.

1. Use a highly viscous ophthalmic viscosurgical agent to fill the anterior chamber and flatten the anterior capsule. A slack anterior capsule will be easier to tear in a controlled fashion. 

 2. Re-grasp the capsulorhexis edge frequently and begin with a smaller capsulotomy than desired. Because of the elasticity of the anterior capsule, the opening will be larger than it appears once the forceps release the capsule flap.

3. Be aware when tearing that force must often be directed toward the center of the pupil in order to control the turning of the CCC edge along a circular path.

4. Stop before the edge is out of sight under the iris if the capsule begins to extend peripherally. We recommend converting to a vitrector cut capsulotomy or a radio frequency diathermy capsulotomy when this occurs.

While a CCC is a reasonable option in patients aged over 2 years, it will be very difficult for even the experienced surgeon in an infant’s eye. Alternate anterior capsulotomy methods described below will be more consistently successful than manual CCC in these patients.

We’ve tested a mechanized circular anterior capsulectomy in both laboratory and clinical settings. This technique, now known as vitrectorhexis, has proved to be a very effective alternative for CCC for young children where the CCC may be difficult to control.⁹
 A third option for creating an anterior capsulotomy in a child involves the use of high-frequency endodiathermy (Kloti bipolar radio frequency capsulotomy instrument (Oertli Instrumente, Berneck, Switzerland)). The focused electromagnetic field of the recently introduced Fugo Blade (Medisurg Research and Management Co., Norristown, Pa.) can be used to perform an anterior capsulectomy.

 • Lens substance aspiration (phacoaspiration). Pediatric cataracts are soft but can be somewhat “gummy.” They don’t require phacoemulsification, and an irrigation-aspiration or vitrectomy handpiece usually aspirates lens cortex and nucleus easily. When using the vitrector, intermittent bursts of cutting can facilitate the aspiration of the more “gummy” cortex of young children. Hydrodissection, meanwhile, is not as consistently performed in children as it is in adults. Further study is needed in order to define accurately whether hydrodissection is as beneficial in pediatric eyes as it has proven to be in adult eyes. 

 • Primary IOL implantation. A consensus exists that IOL implantation is appropriate for most children undergoing cataract surgery beyond their second birthday.¹⁰
 By contrast, the advisability of IOL implantation in infancy is still in question. It is well-known that the majority of the eye’s axial growth occurs during the first two years of life, and this rapid change makes the selection of an IOL power for an infant difficult.

We strongly recommend in-the-bag implantation when placing an IOL in a child’s eye, although it entails carefully avoiding asymmetrical fixation with one

Figure 2a. Implantation of a rigid PMMA intraocular lens following removal of a traumatic cataract. Some Elschnig’s pearls may be seen at the periphery (arrow), but the central visual axis is clear. The traumatic anterior capsule rupture served as a capsulorhexis in this case without needing to be enlarged.

haptic in the capsular bag and the other in the ciliary sulcus, which can lead to decentration of the IOL. Unlike with adults, the dialing of an IOL into the capsular bag can be difficult in children. Often the IOL will dial out of the capsular bag rather than into it. This tendency can be blunted somewhat by the use of highly viscous ophthalmic viscosurgical agents.

Foldable acrylic IOLs are used commonly in children. We’ve found Alcon’s AcrySof acrylic IOL to be very biocompatible for the child’s eye.¹¹
 The newer one-piece AcrySof lens is especially suited for small, soft eyes and can be inserted into the capsular bag with ease. While silicone IOLs are used infrequently in children, the second-generation silicone biomaterial appears to be an acceptable alternative for older pediatric patients. When capsular fixation is not possible, the ciliary sulcus placement of an IOL in a child is acceptable. To avoid decentration, we recommend rigid polymethylmethacrylate IOLs instead of foldable IOLs in cases likely to require ciliary sulcus fixation.

• Secondary IOL implantation. The vast majority of children undergoing secondary IOL implantation have had a primary posterior capsulectomy and anterior vitrectomy. If adequate peripheral capsular support is present, we place the IOL into the ciliary sulcus or in the re-opened capsular bag. Viscodissection and meticulous clearing of all posterior synechiae between the iris and the residual capsule is mandatory.

We recommend PMMA heparin surface modified (HSM) IOLs, rather than a foldable acrylic lens, for sulcus placement. HSM IOLs are more biocompatible for pediatric eyes than unmodified PMMA IOLs, and they develop fewer inflammatory cell deposits.¹²
 While we use foldable IOLs almost exclusively for in-the-bag placement, more rigid PMMA lenses have become preferable for ciliary sulcus placement after several cases in which soft, foldable IOLs became decentered in the child’s ciliary sulcus.

We’ve found prolapsing the IOL optic through the fused anterior and posterior capsule remnants to be useful in preventing pupillary capture and ensuring lens centration.  This maneuver is easier in a very soft vitrectomized eye if a PMMA IOL is used. When inadequate capsular support is present for sulcus fixation in a child, we do not implant an IOL unless every contact lens and spectacle option has been explored fully. When necessary, we use the Alcon C270BD lens for scleral fixation using 10-0 Prolene via an ab externo approach.

 • IOL power selection. Selecting the best IOL power to implant in a growing child presents unique challenges. While investigators have documented the axial growth pattern of normal eyes in children,¹³  controversy still exists about whether the pseudophakic eye grows predictably along that same curve.
In the normal phakic child, there is little change in refraction (0.9 D from birth through adulthood on average), because the power of the natural lens decreases dramatically as the eye grows axially. An IOL placed in a child’s eye cannot change in power to match the growth of the eye, however. One chosen for emmetropia in early childhood is likely to leave the patient highly myopic as he grows older.

Studies are available to help the surgeon predict the growth of the eye on average in children beyond 2 years of age.¹⁴  When operating on children between the ages of 2 and 8 years, many surgeons have advised selecting an IOL power that will leave mild to moderate hyperopia, milder with increasing age. Other authors have advocated aiming for emmetropia regardless of age when operating beyond age 2 years. This approach avoids potentially amblyogenic residual hyperopia but is likely to lead to the development of significant myopia later.

Management of Pediatric Traumatic Cataracts Trauma is a common cause of unilateral cataract in children (See Figure 1 b). At the time of presentation after the trauma to the eye, the primary repair of a corneal or scleral wound may be needed, along with a complete evaluation of damage to the intraocular structures (e.g., posterior capsule rupture, vitreous hemorrhage and retinal detachment). We prefer to defer cataract surgery and IOL implantation in traumatic cataract patients, even when the anterior lens capsule has been ruptured. A delay of one to four weeks may help by allowing corneal healing and reducing the inflammatory response.1  We avoid longer delays in children within the amblyopic ages of 0-8 years, however. In cases of traumatic cataracts with corneal injuries, we prefer to implant an IOL, because contact lenses may be difficult to fit, and we try to place the lens in the capsular bag when capsular support is available. Ciliary sulcus fixation of the IOL may be done in the absence of capsule support but with a greater incidence of uveitis, pupillary capture, etc.2 1. Peterseim ME, Pandey SK, Wilson ME, Elliot L, Saunders R. Outcome of traumatic cataract surgery and intraocular lens implantation in children. J Cataract Refract Surg 2001 (submitted). 2. Pandey SK, Ram J, Werner L, Jain AK, Gupta A, Apple DJ. Visual results and postoperative complications of capsular bag and ciliary sulcus fixation of posterior chamber intraocular lenses in children with traumatic cataracts. J Cataract Refract Surg 1999;25:12:1576-84.

 • Management of the posterior capsule. The advent of vitreous suction cutting devices for removing the center of the posterior capsule and a portion of the anterior vitreous during the initial surgery in young children undergoing cataract surgery dramatically decreased the need for secondary surgery. In our experience, a primary posterior capsulotomy and anterior vitrectomy is mandatory during IOL implantation in the pediatric cataract case for maintaining a long-term clear axis (See Figures 2a, b). Children usually need Nd:YAG laser posterior capsulotomies when the posterior capsule is left intact. These often require larger amounts of laser energy as compared to cataract procedures in adults, and the posterior capsule opening may close, requiring repeated laser treatments or a secondary pars plana membranectomy.

Postoperative Care
When performing pediatric cataract surgery under general anesthesia, we usually place a patch and shield over the eye for the first postoperative night. Immediately at the end of surgery, we instill a drop of dilute (5%) povidone iodine in the operative eye. Next, we place an antibiotic steroid ointment and atropine ointment on the eye prior to the patch and shield. We examine the eye on the first postoperative day.

We prescribe the use of topical atropine (0.5% in children less than 1 year of age, and 1% thereafter) q.d. for two to four weeks, and topical prednisolone

Figure 2b. Slit-lamp photograph showing a well-centered, single-piece Alcon AcrySof IOL. Note the clear visual axis at the last follow-up visit. The anterior capsulorhexis (arrow) and posterior capsulorhexis (arrowhead) are also clearly visible.

acetate six times per day for two weeks, then t.i.d. to q.i.d. for an additional two weeks. The patient uses an antibiotic drop for one week only, and we rarely prescribe oral steroids. Any residual refractive error we correct after the wound stabilizes and the synthetic absorbable sutures dissolve.

The eye patch and shield come off on the first postoperative day. We recommend the use of glasses or the shield during the day and the shield at night for at least one week after surgery. Postoperative examinations are scheduled at two weeks, four weeks, three months and six months postoperatively. Consider yearly examinations under anesthesia in children undergoing cataract surgery in order to measure intraocular pressure, examine the peripheral retina, monitor eye growth using A-scan ultrasound, and examine the position of the IOL and detect any secondary membrane or after cataract formation. Once children become old enough and cooperative enough to undergo these examinations awake, the serial examinations under anesthesia become unnecessary.

These special patients are uniquely challenging. Children do not always comply with postoperative instructions, and examinations of the eye after surgery are also often incomplete. In addition, the long expected life span after surgery for children deserves consideration during surgical decision making.
The best surgical techniques for children will evolve most efficiently with optimal cooperation and collaboration between pediatric ophthalmologists and adult cataract surgeons. 

Supported in part by an unrestricted grant to the Storm Eye Institute from Research to Prevent Blindness Inc. The authors have no financial or proprietary interest in any product mentioned in this article.

Dr. Wilson is the Pierre G. Jenkins Professor and chairman, Department of Ophthalmology, Storm Eye Institute, Medical University of South Carolina. He practices pediatric ophthalmology with a special emphasis on pediatric cataracts, and he may be reached via e-mail at wilsonme@musc.edu.


Dr. Pandey is a postdoctoral fellow at Storm Eye Institute, Department of Ophthalmology. His research interests include adult and pediatric cataracts, pathology and complications of intraocular lenses.

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