"Advancement in instrumentation has made pediatric cataract surgery safer and more reliable," said Dr. Park, assistant professor of ophthalmology, Johns Hopkins University School of Medicine, Wilmer Eye Institute, Baltimore.
"Addressing the needs of pediatric cataract patients worldwide, we need [to develop] better IOL technology for pediatric eyes that will allow for smaller incisions during surgery, and prevent complications and the need for further surgery."
Pediatric cataract surgery differs from adult cataract surgery in a number of ways.
"One of the reasons pediatric cataract surgery is so much more challenging is the size of the eye," she said. "We are dealing with an axial length of 16.4 mm instead of 24 Maintenance medications on average, and the anterior chamber is only about 2 mm deep."
Also, the low scleral rigidity makes it difficult to maintain the chamber during surgery.
"It's about four times more pliable and has only half the tensile strength of the adult sclera," Dr. Park said.
In children, surgeons must also deal with wide-ranging pathology, including fibrous membrane, calcification, and iris-lens adhesion.
"You have to be ready for surprises when you . . . operate on these eyes," she said. "Even after successful cataract surgery, surgeons will be faced with vigorous inflammatory response, posterior capsular opacification, and secondary membrane formation."
The advent of vitreous suction-cutting devices has revolutionized pediatric cataract surgery, making it safer and more reliable, according to Dr. Park. This technology allows surgeons to perform anterior capsulotomy by means of vitrectorhexis, removal of lens, posterior capsulotomy, and limited anterior vitrectomy—all with the same device through a small incision. The latter steps reduce the development of secondary membrane formation, and thus, reduce the number of surgeries.
"We've also gone down in size from 20 gauge to 25 gauge, and perhaps in the future, even to 27 gauge," Dr. Park said.
Other helpful surgical tools include operating microscopes, viscoelastic materials with high molecular weight, intraocular scissors, endgrasping forceps, and capsulorhexis forceps.
"Most importantly, advances in IOL material and design now allow insertion of a lens through a small incision, which makes it possible for us to think about inserting a lens into an infant's eye," she said.
Although surgery has become more refined and safer, there remain extra concerns when it comes to pediatric cataract surgery, Dr. Park continued. One of the most important factors to consider is the timing of surgery.
The incidence of aphakic glaucoma after cataract surgery in children ranges from 15% to 21% at 5 years. The rate of aphakic glaucoma is higher if surgery is performed within 4 weeks after birth. Visual outcomes decline, however, if cataract surgery is performed after 6 weeks of age.
"This gives us an optimal window of time between 4 to 6 weeks of age to perform the cataract surgery, and this is what I recommend for my patients," she said.
Successful cataract surgery is only a small stepping stone to visual correction in young children, according to Dr. Park. Surgeons then must figure out how best to correct the refractive error. IOL implantation and contact lenses are two choices to consider.