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Although some surgeons will venture into premium lens implantation, most continue to prefer monofocal lenses for the youngest patients

Congenital nuclear cataract

Above infant, before surgery (Insert is opposite, normal eye)
Source: JL Derner, Jules Stein Eye Institute

One year after surgey, infant with IOL
Source: M. Edward Wilson, M.D.

Gone are the days of thinking IOL implantation in a pediatric population is ineffective. The debate is now centered on two main areas: How early in a child’s life is it appropriate to implant a lens, and what types of lenses are appropriate for eyes that are not yet fully developed?
The degree of amblyopia coupled with the age of the patient are the critical factors regarding lens implantation, experts say.
“In general, in pediatric ophthalmology—especially in the amblyopic age group—we’ll implant monofocal lenses,” said David B. Granet, M.D., director of pediatric ophthalmology and adult ocular realignment services, Ratner Children’s Eye Center and Shiley Eye Center, University of California, San Diego. Dr. Granet said he has implanted a multifocal—just once—in a 9-year-old, but concerns about amblyopia were minimized and the patient “showed a good potential outcome.”
“In the pediatric population, we use monofocal lenses most often, and the preferred implant is hydrophobic acrylic,” said M. Edward Wilson, M.D., director, Albert Florens Storm Eye Institute, Medical University of South Carolina, Charleston, S.C. Dr. Wilson will typically implant the AcrySof SN60 wavefront (Alcon, Fort Worth, Texas), an aspheric optic that includes blue light-filtering chromophore technology.
“In reality, there are very few multifocal implantations in this population,” he said. “The technology used to make multifocal implants works well if the biometry and predictability are good. But the eye is still growing in children, so the main issue becomes this: The best use of multifocal technology is dependent and precise with which lens to implant, and the eye cannot change. Once the eye starts to change, any ability to be spectacle-free goes away.”
Children can “all accommodate before they undergo cataract surgery,” he said. “So we really are taking something away. Blur has to be significant enough to justify taking away the smooth accommodation they have naturally. As cataract gets worse, it’s worth the tradeoff. While 20/40 may be acceptable in an adult, it’s not for a child. Before surgery, we have to ensure the blur is of significant impact to daily activity. It gives us, as surgeons, more pause to err on the side of caution.”
Samuel Masket, M.D., clinical professor of ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, University of California, Los Angeles, said the concept of the presbyopia-correcting lenses is spectacle independence.
“With most pediatric cataract cases, they will undergo a refractive change over time. There’s no advantage to implanting a presbyopia-correcting lens if there remains a need for spectacles,” he said. “Those lenses will reduce contrast sensitivity. When I do implant them, I reserve them for children age 7 or older.”
Dr. Masket has used the presbyopia-correcting lenses in cases of uniocular cataract, he said. In that setting, “in the few I’ve implanted, the patients have done really well, as long as there was no large degree of astigmatism or amblyopia. I think they can be successfully used in limited numbers, in specific situations,” he said.
Dr. Granet disagrees. “In a developing visual system where the goal is perfect vision, a multifocal lens is not going to achieve that goal,” he said. “It’s up to us as physicians to be careful about which scenarios may be appropriate.”
In some instances where a pediatric patient was implanted with a multifocal lens, Dr. Wilson said the child became more myopic and “ironically, more spectacle dependent with the multifocal than they would have been with a monofocal lens. In children, the mild-to-moderate myope is not unhappy with monofocality. It’s a really different situation than with an adult population.”
His concern about implanting presbyopia-correcting lenses in very young children is that “we’re worried about amblyopia, we don’t want to induce glare or halo or reduce contrast sensitivity, and it’s unknown if these lenses would decrease our ability to improve amblyopia,” Dr. Wilson said.
The conundrum, Dr. Wilson said, is that post-surgery, children will be forced to wear spectacles. “Do we leave them hyperopic on purpose and weaken the spectacles over time as the eye grows, or do we resolve their refraction early on, leaving them initially spectacle-free but becoming more myopic as they age?”
Because multifocal lenses are not focused on the retina, “it’s hard to make claims about what extra they’re giving the patient,” Dr. Wilson said. “I discuss the premium lens options for children as they approach full growth. There are teenagers with good vision potential with developmental-acquired cataract—sometimes those kids are almost fully grown and (understandably for a teenager) don’t want to have to pull out ‘granny glasses’ on a date,” he said. A paper his group is publishing shows that a 4 D change in power is needed between ages 10 and 20.
“We are continually surprised at how much refraction changes after the initial IOL implantation,” Dr. Wilson said.

Correcting astigmatism

Performing cataract surgery in children is “very different from performing it in an adult patient,” said Dr. Masket, who has extensive experience with the latter as well.
“In children, if you operate from a temporal incision, you’ll have significant with-the-rule astigmatic change, but if you operate superiorly, the eye will be astigmatically neutral,” Dr. Masket said. “Virtually every child has with-the-rule astigmatism; we are absolutely incapable of changing childhood astigmatism with limbal relaxing incisions.” He cites cases of his own where he has created limbal relaxing incisions (LRIs) as much as 8 mm long “and haven’t changed the astigmatism by more than half a diopter.”
He advised other surgeons to use a toric lens in cases with a high degree of cylinder.
Astigmatic correction “raises a whole series of questions in this population,” Dr. Granet said. “There is usually significant higher order aberrations as well … I fully expect in my career to see increased data that will warrant our use of refractive surgery in very isolated, proper cases.”
Likewise, “a pure accommodating lens might be appropriate in the future for the pediatric contingent,” he said. “Some residents are so comfortable with implanting the newer technology, it trickles down. As our training for adult cataract has shifted, so will the training for pediatric cataract.”
The dilemma over how to resolve astigmatism is that “there doesn’t seem to be enough data to know for certain—there is anecdotal evidence that undercorrection of a child is preferred. LRIs don’t seem to be overly successful,” Dr. Wilson said. He has performed LRIs in conjunction with multifocal implants in older children, but usually “does that under the watchful eye of a corneal specialist.”
Children—and their parents—are expecting to wear spectacles after surgery, “which means we don’t fuss as much about astigmatism,” Dr. Wilson said.
He added that with any child over the age of 8 or 10, “we make sure the parents understand that options like the multifocal lenses exist, but we don’t necessarily recommend them. We discuss a little about why there isn’t much of an advantage for a child in using multifocal lenses. We reiterate that we use the smallest incisions, best implant material, etc. We’re confident—and they need to be confident—that the lens material will be intact 70 years later,” Dr. Wilson said.
Because almost 40% of the pediatric cataract market is Medicaid, with 60% having private insurance, most parents are not in a position to pay additional monies for the premium lenses “if there’s no guarantee there would be ‘perfect’ vision,” Dr. Wilson said.

The parent factor

Any time a child presents for surgery, “there are extended discussions that have to occur with the parents,” Dr. Granet said. “That discussion has to include follow-up like patching, drops, etc., as well as the limitations of current technology.”
As surgeons, “we’re mandating glasses for the child; unilateral-sided glasses are sometimes awkward for children,” he said. When to implant is still open for discussion, although results from the Infant Aphakia Treatment Study indicate IOL implantation in children as young as 2 years old can be successful.
“Still, this is an inherently less compliant population, with an inherently changing visual system and growing eye. The less compliant the parent is about patching, etc., the greater the likelihood the child will develop amblyopia,” Dr. Granet said.
In his opinion, a “vibrant, healthy, active ciliary body that can compress a lens and can make it accommodate may mean children would be better off with an accommodating lens instead of a monofocal one,” Dr. Granet said.
Parents are often more difficult than the typical premium lens patient, upon occasion not wanting their child to be beholden to spectacles, and that insistence may alter the treatment, he said.
“If you have multiple refractive powers in a lens, they can develop meridional amblyopia,” he said. “If we give them plano distance at 4 years old, when they’re 10 they’ll lose that. However, if we provide them the best possible vision at age 4, and at 12 or 15 they undergo refractive surgery to fix the refraction, that’s not a crazy concept, even if it’s not the way we would typically start the discussion about treatment options.”

Surgical (and other) pearls

The axial lengths and K readings can continue to change until someone reaches age 20; in cases with unilateral cataract, that eye will grow a “bit more than the ‘OK’ eye in the second decade of life,” Dr. Wilson said.
Most pediatric cataract surgeries are done under general anesthesia, Dr. Wilson said. “I tend to leave a bit of hyperopia to minimize the refractive errors when they’re grown,” he said. “I do a primary opening in the posterior capsule up to about age 7 or 8.” He advises in older children to have careful follow-up when there’s an intact posterior capsule and to perform YAG early.
“Most surgeons who are used to performing cataract surgery on an adult population will be surprised if they see just how thick the capsule is in a pediatric patient,” he said. “In my experience, even with a good opening, capsulotomy will close and will need to be redone. We advise doing more primary posterior capsulorhexis openings in children. As they get older, you can do it in more adult-like ways—wait for the first signs of a drop in vision and do YAG then. With square-edged AcrySof lenses in older children, our YAG rate is still about 50%. If we didn’t have the quality of the implants now available, the YAG rate would be much higher.”
Regardless of initial outcomes, Dr. Wilson recommends performing a YAG laser capsulotomy 18 months after surgery.
“If the cells are going to grow, it will start around 18 months post-operatively. But if you leave a clear capsule, we haven’t found a need to YAG in the early post-op period.” Dr. Granet highly recommends that cataract surgeons partner with a pediatric ophthalmologist so the difficult issue of obtaining the Ks and A scans is more easily managed.
“Symmetry in pediatric eyes may not be likely, the posterior capsule may be torn, etc.,” Dr. Granet said. “Be prepared. Children’s eyes are completely different in softness vs. firmness. Their eyes are much more giving as you push. The fluid dynamics feel different. Anterior capsules are elastic. If you’re tearing the capsulorhexis, it may circle outwardly.”
Further, pediatric surgeons need to determine if they will give the child great vision immediately after the initial surgery, or if the child will grow into the lens power chosen, Dr. Granet said.
Parents are making the decision for their child, and “that’s a difficult thing to do,” Dr. Masket said. “There’s a significant onus on them. They need to understand the benefits of the different approaches for their child; finances come into play. It’s a third-party decision, so it’s a little strange when compared to an adult cataract patient.”
Additionally, most IOLs will necessitate a compassionate device exemption for implantation into a pediatric patient, Dr. Masket said.
“We had to write a special pediatric assent so the child can understand it,” he said.
If the child has unilateral cataract, “never advise a multifocal implant. The multifocality of the lens is never going to be able to compete with normal youthful accommodation, so you don’t need it,” Dr. Wilson said. “If it’s an older child and you’re going to the trouble of using a multifocal lens in that child, you have to limit the accommodation.”

Editors’ note: Drs. Granet, Wilson, and Masked have no financial interest related to their comments.