gms | German Medical Science

Pediatric cataract surgery is a complex issue best left to surgeons that are familiar with its long-term complications and lengthy follow-up. Treatment is often difficult and tedious and requires a dedicated team effort, the most important members being parents. At one point, lensectomy was the standard treatments used in such cases. However, in recent times, small incisions, anterior capsulorhexis, bimanual irrigation/aspiration, and primary posterior capsulectomy and vitrectomy have become acceptable treatment options for infantile cataract. Intraocular lens implantation has become the standard of care for the optical rehabilitation of children with cataract from the toddler age group and up.

Anterior Capsule Management: The anterior capsule in children is very elastic, and therefore it may be difficult to perform a controlled manual continuous curvilinear capsulorhexis (CCC). However, it remains a gold standard for resistance to tearing and should be accomplished whenever possible. Difficulties of performing manual CCC in infantile eye led researchers and surgeons to search for alternative methods to open the anterior capsule in children. Alternatives to manual CCC currently available include vitrectorhexis, radiofrequency diathermy with a Fugo plasma blade, the two incision push pull technique, and the four incision technique. Wilson analyzed pediatric anterior capsulotomy techniques using porcine model and found that manual capsulorhexis produced the most extensible capsulotomy with most regular and stable edge. In eyes with poor anterior capsule visibility, trypan blue (0.0125%) was used to stain the anterior capsule. The shape, size and edge integrity of anterior capsulotomy are very important for long-term centration of the IOL.

Management of the Posterior Capsule and Anterior Vitreous Face: The most frequent and significant problem following pediatric cataract surgery is VAO.Maintenance of a clear visual axis remains a high priority when planning management of the posterior capsule in the amblyogenic age range. An important question that remains is when should the posterior capsule be left intact? Primary posterior capsulectomy (with or without anterior vitrectomy) are considered “routine surgical steps”, especially in young children. A manual PCCC offer the advantage of a controlled size and strong edges but is more difficult to perform. Many investigators have observed that performing manual PCCC is technically difficult. A potential complication associated with this procedure is the disruption of the AVF. The signs of AVF disruption vary from subtle to obvious. 1) the presence of vitreous strands in the anterior chamber. 2) The attachment of the vitreous to the capsular flap. 3) Distortion of the capsulorhexis margin. Recently we described a technique to render the vitreous visible to the anterior segment surgeon. On completion of the PCCC, 0.1 ml of a suspension of preservative free triamcinolone acetonide (Aurocort, Aurolab India) was injected for visualizing the anterior vitreous face as well as the presence and extent of vitreous in the anterior chamber. After vitrectomy, if the surgeon hasn’t cleared the residual vitreous strands triamcinolone can now be used second time to clearly identify the superficial vitreous gel which may have otherwise gone unnoticed. After IOL implantation and removal of the residual OVD, the surgeon again injects 0.1 ml of the suspension into the anterior chamber. Additional anterior vitrectomy was performed if vitreous strands were identified in the anterior chamber.

Intraocular Lens (IOL) Implantation: One of the most important preoperative considerations is whether to implant an IOL or not. Surgeons should be prepared for the common question “Would you implant an IOL if this were your child?” The capability of the IOL to offer constant visual input is an important advantage for the better visual outcome after pediatric cataract surgery. Use of IOL provides at least a partial optical correction at all times. Because of the advantage it offers, primary IOL implantation has slowly gained acceptance for the management of childhood cataracts. However, as of 2007, use of IOL remains controversial for the management of infantile cataract.The important concerns about primary IOL implantation during infancy are the technical difficulties of implanting an IOL and selecting an IOL power, and the higher rate of visual axis opacification (VAO). At present, only adult sized IOLs are available, which are often difficult to implant in these small eyes and may cause complications over the long run. Currently available adult sized IOLs are slightly oversized and at times may not fit into small infantile eyes.

The size of the posterior capsulorhexis should be large enough to provide a clear central visual axis, but smaller than the IOL optic, so as to allow stable in-the-bag IOL fixation. Even if the surgeon is not planning to implant an IOL in a specific eye, it is important to leave behind sufficient anterior and posterior capsular support at the time of cataract surgery to facilitate subsequent IOL implantation. The common practice is to perform posterior capsulectomy and anterior vitrectomy before IOL implantation if the limbal approach has been used whereas, if a pars plana vitrectorhexis is performed, it is done after the IOL is implanted. Further there is no agreement on whether the IOL should be implanted before or after the primary posterior capsulectomy. Some surgeons perform a pars plicata capsulectomy and vitrectomy with the vitrectome after implanting the IOL in the bag. Both PMMA and hydrophobic acrylic foldable IOLs have been widely used in pediatric eyes. However, several studies have now shown that hydrophobic acrylic IOLs are preferable as they offer better uveal biocompatibility and decreased incidence of VAO, with hydrophobic acrylic IOLs causing a delayed onset of PCO.For bilateral cataract during first year, aphakic glasses and/or contact lens use may be a reasonable option; however, for unilateral cataract, we are truly equipoised between whether or not to offer primary IOL implantation at the time of infantile cataract surgery. A large randomized clinical trial – the Infant Aphakia Treatment Study (IATS) is currently underway to compare primary IOL implantation to contact lens correction in children undergoing unilateral cataract surgery in the first six months of life.

Sealed Capsule Irrigation: Maloof and associates have designed a sealed capsule irrigation device (Perfect CapsuleTM) that can help to selectively irrigate the capsular bag. This may help pediatric cataract surgeons to eliminate or delay VAO by using such chemicals through this device.

Manual PCCC via Pars plana approach: Vasavada and coauthors recently introduced a technique of performing manual PCCC via pars plicata. After implantation of the IOL in the capsular bag all the incisions are sutured with 10-0 nylon and residual Provisc is left in the anterior chamber. The pars plicata entry is made 1–1.5 mm behind the limbus and an initial puncture is made in the center of the posterior capsule and later a coaxial capsulorhexis forceps was introduced and a flap is generated .The edge of the flap is grasped and then re-grasped every 2 clock hours fashioning the PCCC in a clockwise manner.

Bag-in-the-lens implantation: Tassignon and colleagues reported the outcome of a surgical procedure they called ‘bag-in-the-lens’ in pediatric cataractous eyes In this technique, the anterior and posterior capsules are placed in the groove of a specially designed IOL after a capsulorhexis of the same size is created in both capsules The principle behind this IOL design is to ensure a clear visual axis by mechanically tucking the two capsules into the IOL, thereby preventing any migration of proliferating lens epithelial cells.

Heparin in irrigating solution: Heparin has been used in intraocular irrigating solutions to reduce inflammatory reactions after pediatric cataract surgery. It has been documented that infusion of enoxaparin, a low molecular weight heparin, during pediatric cataract surgery may minimize the postoperative inflammatory response.

Posterior capsulorhexis combined with optic buttonholing: Recently R. Menapace introduced Posterior optic buttonholing (POBH) a safe and effective technique which not only excludes retro-optical opacification, but also withholds capsular fibrosis by obviating direct contact between the anterior capsular leaf and the optic surface.

While dramatic advances have occurred in this field over the past 10 years, some technical aspects of surgery, changing refraction and functional outcome continue to pose significant problems. Primary management of the posterior capsule is mandatory depending on the age of the child at surgery. With refinements in surgical techniques, improvisation of IOLs and better understanding of growth of the pediatric eye, in the coming years IOL implantation is likely to become an established mode of treatment of children even in the youngest age group.