This article is more than 5 years old. Information may no longer be current.
Pediatric cataract surgery with IOL implantation remains a challenge
A surgeon explains various surgical and management techniques and the accompanying complications and issues.
Click Here to Manage Email Alerts
Pediatric cataract surgery remains a surgical challenge, even for the well-experienced surgeon, and demands a composite group approach that includes committed and educated parents, an experienced pediatric cataract surgeon, and a pre- and postoperative pediatric eye care team that addresses all the demands of a growing eye. With 1.5 million blind children globally, of whom 1.3 million are located in Asia, pediatric cataract poses a challenge to ophthalmologists worldwide.
A shift from lensectomy to modern-day surgical approaches, including small incisions, anterior capsulorrhexis, bimanual irrigation and aspiration, primary posterior capsulectomy and vitrectomy, has paved the way to better outcomes in infantile cataracts.
In this column, Dr. Vasavada describes the various aspects of pediatric cataract surgery techniques and the decision-making process in these challenging cataracts in children.
Thomas “TJ” John, MD
OSN Surgical Maneuvers Editor
Abhay R. Vasavada
Visually significant cataracts in children call for prompt surgical intervention to clear the ocular media and provide a focused retinal image. IOL implantation has become the standard of care for the optical rehabilitation of children with cataract from the toddler age group and up. The timing of treatment is crucial to the visual development and successful rehabilitation of children. Unilateral congenital cataract surgery within 6 weeks of birth produces the best visual outcomes. The equivalent “latent” period for bilateral visual deprivation may be longer, at around 10 weeks. It is important to keep the time interval to a minimum between the two eye surgeries.
Surgical technique
Pediatric cataracts need a special surgical strategy because these eyes have greater elasticity of the capsule, lower scleral rigidity, higher incidence of posterior capsular opacification, thick vitreous gel, and a miniature but growing eye. Adhering to the principles of a closed-chamber technique, such as creation of an incision, injection of viscoelastic before removing any instrument from the eye, bimanual I&A and anterior vitrectomy, remains a pivotal issue.
Anterior capsule management
The anterior capsule in children is very elastic, adding to the difficulty of performing a controlled, manual continuous curvilinear capsulorrhexis (CCC), which remains a gold standard and should be accomplished whenever possible. Current alternatives to manual CCC include vitrectorhexis, radiofrequency diathermy with a Fugo plasma blade, two-incision push-pull technique, and four-incision technique. In eyes with poor anterior capsule visibility, trypan blue 0.0125% may be used to stain the anterior capsule.
Management of posterior capsule, anterior vitreous face
Visual axis obscuration (Figure 1) remains the most frequent and significant problem. In the amblyogenic age range, maintenance of a clear visual axis remains a high priority. An important question is when should the posterior capsule be left intact. Primary posterior capsulectomy, with or without anterior vitrectomy, is considered a routine surgical step, especially in young children. A manual posterior continuous curvilinear capsulorrhexis (PCCC) offers the advantage of a controlled size and strong edges but is more difficult to perform (Figure 2) and carries a potential complication of anterior vitreous face disruption. However, anterior vitreous face disruption often goes unnoticed because anterior vitrectomy is a part of the surgical strategy in younger children. The signs of anterior vitreous face disruption include vitreous strands in the anterior chamber, vitreous attachment to the capsular flap and capsulorrhexis margin distortion.
Figure 1. Proliferative PCO in an 8-year-old child with a single-piece AcrySof (Alcon) at 1.5 years of follow-up.
Images: Vasavada AB
Figure 2. Primary manual anterior and posterior CCC showing a smooth and regular edge.
We have described a technique using preservative-free triamcinolone acetonide (Figure 3) to render the vitreous visible and ensure a complete anterior vitrectomy after a manual PCCC, with or without IOL implantation. PCCC alone may delay the onset of PCO but cannot eliminate it. The inflammatory response in small children is severe, and fibrous membranes may form on the intact anterior vitreous face, resulting in visual axis obscuration. Hence, anterior vitrectomy and posterior capsulotomy are advocated in infants and young children (Figure 4). PCCC with vitrectomy acts as a scaffold and therefore prevents obscuration of the central visual axis.
Most pediatric cataract surgeons prefer bimanual anterior limbal vitrectomy over pars plana vitrectomy. Some surgeons prefer pars plicata vitrectorhexis after in-the-bag IOL implantation. When a pars plicata approach is chosen, the IOL should be inserted into the capsular bag using an ophthalmic viscosurgical device while the posterior capsule is still intact. While the irrigation cannula remains in the anterior chamber, an MVR blade is used to enter pars plana 2 mm to 3 mm posterior to the limbus. This can vary, depending on the patient’s age: 1.5 mm to 2 mm in patients younger than 1 year, 2.5 mm in patients between 1 year and 4 years, and 3 mm in patients older than 4 years. The vitrector is then inserted through this incision and used to open the center of the posterior capsule. However, considering the implications of vitrectomy, especially in children with a family history of myopia or diabetes mellitus, and due to the possibility of cystoid macular edema, posterior capsule management has been stratified according to the age of the child. Children younger than 3 years are subjected to PCCC and anterior vitrectomy, children between 3 years and 6 years are subjected to PCCC without vitrectomy, and children older than 6 years do not receive PCCC.
Figure 3. Vitreous strands extending toward the incision clearly seen with triamcinolone staining.
Figure 4. Primary anterior limbal vitrectomy being performed in a 1-year-old child.
IOL implantation
The capability of an IOL to offer constant visual input is an important advantage for a better visual outcome after pediatric cataract surgery. Use of an 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. 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.
Posterior capsulorrhexis size should be large enough to provide a clear, central visual axis but smaller than the IOL optic to allow stable in-the-bag IOL fixation. Even if the surgeon is not planning to implant an IOL during the primary surgery, it is important to leave behind sufficient anterior and posterior capsular support to facilitate subsequent IOL implantation. Hydrophobic acrylic IOLs are preferable because they offer better uveal biocompatibility, decreased incidence of visual axis obscuration and delayed onset of PCO. For bilateral cataracts during the first year, aphakic glasses and/or contact lenses may be a reasonable option; however, for unilateral cataract, we do not have a clear answer as to whether or not to offer primary IOL implantation at the time of infantile cataract surgery.
Summary
In pediatric cataract surgery, some technical aspects of surgery, changing refractions and functional outcomes continue to pose significant problems. Primary management of the posterior capsule is mandatory depending on the age of the child at the time of surgery. With refined surgical techniques, improved IOLs, and better understanding of eye growth, IOL implantation is likely to become an established mode of treatment in children, even in the youngest.