Anterior Segment Cataract
Figure 4: A Central Clear Visual Axis after Performing Optic Capture
Secondary Intraocular Lens Implantation Eyes that are left aphakic are likely to require a secondary IOL implantation. Even if the surgeon is not planning to implant an IOL primarily, it is important to leave behind sufficient anterior and posterior capsular support at the time of cataract surgery to facilitate in-the-bag or sulcus-fixated IOL implantation to allow ciliary sulcus or in-the-bag placement of an IOL once the child and eye grow.
Newer Approaches Optic Capture
Intraocular Lens Implantation
One of the most important pre-operative 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 a better visual outcome after pediatric cataract surgery. Use of IOL provides at least a partial optical correction at all times. As a consequence 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 VAO.28–37
At present, only adult-sized IOLs are available, which are often difficult to implant in infantile eyes and may cause complications in the long run.
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 is used, whereas if a pars plana vitrectorhexis is performed, it is done after the IOL is implanted. Furthermore, there is no agreement as to 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 polymethyl methacrylate and hydrophobic acrylic foldable IOLs have been widely used in pediatric eyes. However, several studies show that hydrophobic acrylic IOLs are preferable as they offer better uveal biocompatibility and a decreased incidence of VAO, with hydrophobic acrylic IOLs causing a delayed onset of posterior capsule opacification (PCO).38–42
For bilateral
cataract during the first year, aphakic glasses and/or CL 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 is currently underway to compare primary IOL implantation to CL correction in children undergoing unilateral cataract surgery in the first six months of life.
46
An alternative technique to stabilize the IOL was introduced with the concept of capturing an IOL optic through anterior capsulorhexis. The haptics were placed in the ciliary sulcus and the IOL optic was then placed through the anterior capsulorhexis to ‘capture’ the IOL for stable optic fixation. This concept has been used to develop the technique of posterior capsulorhexis with optic capture through posterior capsulorhexis (haptics in the bag) to prevent PCO.43–51
Conventional or posterior optic capture can be achieved by capturing the optic through anterior capsulorhexis (haptics in the ciliary sulcus, optic in the bag), both the rhexes (haptics in the ciliary sulcus, optic behind the posterior capsule), and posterior capsulorhexis (hepatics in the bag, optic behind the posterior capsule). The third concept is also known as optic buttonholing. The posterior capsule lies on top of the IOL optic and the LECs, which are deviated anteriorly, no longer have access to the retrolenticular space. The optic–haptic junction is the only place in which there is no opposition between the leaflets of the anterior and posterior capsules (Figure 4).
Sealed Capsule Irrigation
) that can help to irrigate the capsular bag selectively, which may help pediatric cataract surgeons to eliminate or delay VAO by using irrigation chemicals through this device.52–55
Maloof and co-workers designed a sealed capsule irrigation device (Perfect CapsuleTM
Manual Posterior Continuous Curvilinear Capsulorhexis via Pars Plana Approach
Vasavada and co-workers recently introduced a technique of performing manual PCCC via the pars plicata.56
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 is introduced and a flap generated. The edge of the flap is grasped and then re-grasped every two clock hours, fashioning the PCCC in a clockwise manner.
Bag-in-the-lens Implantation
Tassignon and colleagues reported the outcome of a surgical procedure in pediatric cataractous eyes that they called ‘bag-in-the-lens’.57,58
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, and thereby prevent any migration of proliferating lens epithelial cells.
US OPHTHALMIC REVIEW
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