Experts explore challenges of successful pediatric cataract surgery

Cataract surgery is more complex in children than in adults, and experts say that all aspects of the surgical process, not just the actual procedure, require great attention.

“The presurgical process is more involved, and certainly long-term follow-up may involve patching and drops, counseling parents, compliance, monitoring changes in eye growth, exchanges of implants, etc., all of which present a special set of extra challenges when dealing with children,” M. Edward Wilson, MD, OSN Pediatrics/Strabismus Board Member, said.

“The patient’s outcome is far better if you have involved, committed and educated parents. The more engaged, the better the outcomes,” he said.

An estimated 1.4 million children are blind worldwide, with 1 million living in Asia and 300,000 in Africa. Congenital cataracts are responsible for about 10% of all vision loss in children. Overall cumulative risk for cataract is one in 1,000 children, according to Dr. Wilson, the Pierre G. Jenkins Professor and Chair, Storm Eye Institute, Medical University of South Carolina.

M. Edward Wilson, MD, an OSN Pediatrics/Strabismus Board Member, said that there are additional challenges inherent in performing cataract surgery in children. Image: Chris & Cami Photography LLC

The treatment approach and challenges of pediatric cataracts vary for patients depending on their age and the morphology of the cataract.

Experts who spoke with Ocular Surgery News agreed that some of the major issues surrounding pediatric cataract surgery include compliance, eye growth and refractive change, capsular management, use of anesthesia, type and power of IOLs, sutured IOLs, and risk of subsequent glaucoma.

“Early diagnosis, appropriate timing of the surgery, if necessary, pre- and postoperative care, and proper treatment of amblyopia are all additional challenges that contribute to the success of surgery and the patients’ outcomes,” Robert S. Gold, MD, OSN Pediatrics/Strabismus Section Editor, said.

Pediatric vs. adult cataract surgery

Edward G. Buckley, MD, vice dean of medical education and professor of ophthalmology and pediatrics at Duke University School of Medicine, said the benefits of cataract surgery are more significant in children than in older adults because there is a lifetime effect in children.

“In a child, the vision system is still developing, so any visual disturbance can result in permanent loss,” he said. “But the benefits of this surgery are definitely clear. If you don’t take the lens out, the child will become essentially blind, but if you do take the lens out, you need to do the arduous tasks involved with follow-up.”

While there are many factors that distinguish pediatric cataract surgery from adult cataract surgery, perhaps the most obvious challenge is that the child is less likely to remain still when undergoing the examination and operation, so the risk for complications is much higher, according to Dr. Buckley.

Additionally, a child’s eye size is much smaller and the tissue is different. A child’s cataract tends to be more complicated, and there is significantly more inflammation requiring more postoperative medication to calm the eye, Dr. Buckley said. It is also common to see pre-existing plaques on the posterior capsule.

“Pediatric cataracts present a completely different set of decision-making and surgical challenges compared to adult cataracts,” David A. Plager, MD, professor of ophthalmology and director of the Section of Pediatric Ophthalmology and Adult Strabismus at Indiana University Medical Center, said.

Dr. Plager published an article in the March 2011 issue of the American Academy of Ophthalmology’s Focal Points to educate surgeons and pediatric ophthalmologists on issues they may find when presented with a child with a cataract.

For one, cataracts at a young age can have a devastating impact on the child’s visual development in one or both eyes. There is also the issue of having to work on a developing eye. As the eye grows front to back, the lens changes shape to offset the axial growth of the eye, according to Dr. Wilson.

“When we do cataract surgery, we are interrupting that growth and ultimately changing the refraction, so we have to plan on that, and it can be very difficult to predict,” he said.

Typically, surgery is more difficult in a child because the anterior capsule is more elastic and there is the challenge of dealing with a posterior capsule with a 100% rate of opacification if left in place, according to Dr. Wilson.

“Consequently, issues such as predicting the appropriate lens power for IOL implant are paramount,” Dr. Plager said.

Additionally, the healing response with pediatric cataract surgery is different, relying on the compliance of parents to properly care for their children.

Diagnosis, preop management

The first step of diagnosis is to determine the location and severity of the cataract. Pediatricians need to screen their patients for cataracts and any other eye complications with the utmost of care, using a direct ophthalmoscope to determine a normal or abnormal red reflex to ensure accurate diagnosis, Dr. Gold said.

Robert S. Gold

“This should be done on all visits to the pediatrician, multiple times if there is a family history of this,” he said. “Pediatricians look at every other body system to make sure the baby is reaching every milestone; this should be one of those milestones.”

Dr. Wilson said that when examining small children, the most valuable tool for diagnosis in the ophthalmology office is the retinoscope because it reveals the cataract shape, location and density and may show optical distortion for several more millimeters beyond the edge of the cataract. All of this can be done at an arm’s length before using a slit lamp.

“If the cataract completely blackens the central red reflex, that is a danger sign right there,” he said.

Once a diagnosis is established, the question turns to whether to perform the surgery. Scott R. Lambert, MD, R. Howard Dobbs professor of ophthalmology at Emory University in Atlanta, said a dense cataract larger than 3 mm is an indication that surgery is needed.

Some patients may have cataracts that are small and not visually significant but may still develop anisometropia or amblyopia. If the visual inattentiveness seems out of proportion to the degree of cataract, amblyopia may need to be treated first to see how it improves, Dr. Lambert said.

Beyond diagnosis and management, a full systemic workup should be done to determine any possible root cause for the cataracts. A unilateral cataract in an otherwise healthy child may not require a workup. However, bilateral cataracts tend to be a marker of genetic disorders, metabolic diseases, type 1 diabetes or even congenital rubella in the developing world, according to Dr. Wilson. The experts agreed it is important to gather information to establish the progression before advancing to surgery.

Aspects of surgery

The majority of the effort in restoring vision after diagnosis requires careful monitoring and treatment of refractive error, amblyopia, and long-term complications and follow-up, according to Erin D. Stahl, MD, OSN Pediatrics/Strabismus Board Member and a pediatric ophthalmologist at Children’s Mercy Hospital in Kansas City, Mo.

Erin D. Stahl

The main goal of pediatric cataract surgery is to remove the opaque lens, which impedes visual development, Dr. Stahl said. If identified and removed promptly, and if amblyopia and refractive error are closely monitored and treated, the child can go on to develop functional vision.

However, she said there are some cases in which the patient may not benefit from cataract surgery. These cases depend on factors such as the age of the patient when the cataract presented and the size of the lens opacity; in addition, surgeons need to consider if the eye is maldeveloped and may have a poor visual outcome once the cataract is removed. Risks associated with all intraocular surgeries include infection, bleeding, retinal detachment, glaucoma and loss of the eye, according to Dr. Stahl.

“The surgeon must weigh the potential benefits vs. the surgical risks when removing a pediatric cataract,” she said.

While the benefits of surgery are not always clear-cut, Dr. Wilson said the long-term benefit is.

“If we can make the child’s vision normal, the number of blind years prevented per patient is so much greater in kids compared to adults. We’re talking 50 to 70 years,” he said. “Cataract surgery is the one way to prevent blindness in kids.”

However, timing of the surgery in this population is yet another challenge.

“With congenital cataracts, the question remains when this should be done,” Dr. Gold said. “The general consensus is somewhere around 8 to 10 weeks of age is enough time, in most cases, to perform this surgery on a child that has a congenital cataract.”

Regarding anesthesia use, children require general anesthesia for cataract surgery and possibly for biometry and postoperative exams depending on the cooperation of the child.

“Pediatric anesthesia is very safe and efficient these days with quick wake-up and rapid return home,” Dr. Wilson said.

IOL use in pediatric patients

Dr. Gold said that cataract surgery with unilateral and bilateral IOL implantation can provide a beneficial effect on final visual outcomes in children who are operated on before abnormal foveolar function develops.

Correct IOL selection is a hot topic, according to Dr. Buckley, because of the difficulties with biometry measurements and IOL calculations in this population.

The age at which to implant an IOL vs. leaving the child aphakic has been the subject of debate for many years. Dr. Lambert said his personal opinion is that children older than 6 months of age will do better with an IOL than a contact lens.

The Infant Aphakia Treatment Study (IATS), conducted by Drs. Wilson, Lambert, Buckley, Plager and colleagues, aims to answer questions about visual outcomes in 114 infants between 1 and 6 months of age who have a unilateral congenital cataract and are treated with primary IOL implantation vs. contact lens. Researchers evaluated visual acuity and adverse events; contact lenses were used to correct aphakia in those who did not receive IOLs.

Early results of 1-year primary outcome data, presented at Kiawah Eye 2010, showed no statistically significant difference in visual acuity in the contact lens vs. non-contact lens group at 1 year, according to Dr. Wilson.

However, complications were higher in the IOL group, with patients returning for a second operation more frequently after primary implantation (63% vs. 12%; P < .001). Most of these additional operations were to clear lens reproliferation and pupillary membranes, according to the study published in the July 2010 issue of Archives of Ophthalmology.

Based on these preliminary results, Dr. Wilson said to be “cautious when using IOLs in patients in the first 6 months of life until this study is followed for a longer time. Every child with cataracts will need an IOL, but the question is, when should that happen?”

“Based on these findings and the fact that refractive power prediction is inaccurate in very young children, I recommend IOL placement to parents with children 1 year or older,” Dr. Stahl said. “Most older children are candidates for IOL except in some cases of microphthalmia, trauma, lens dislocation or uncontrolled uveitis.”

Results of the IATS are ongoing, and the researchers will follow patients to 5 years of age. Secondary outcomes will include parental stress associated with managing the child’s condition and patient adherence to the discretionary patching protocol.

Multifocal IOLs and sutured lenses

Another issue with IOLs is selecting what power of lens to implant, Dr. Buckley said. Because the child’s eye is still growing and will continue to do so until the child is in his or her late teens, whatever lens is inserted will not be correct years later.

“Even if you try to predict what the refraction would be, we have a hard time determining what the final outcome will be,” he said. “The question becomes, should we implant multifocal IOLs in children because of this?”

Dr. Stahl said that advocates of multifocal IOLs in children argue that they can lead to improved stereopsis in unilateral cases and avoid the need for bifocals and glasses, while critics have concern about making amblyopia treatment more difficult due to loss of contrast sensitivity. Spectacle independence may not be achieved because eye growth becomes an unpredictable target.

Additionally, Dr. Buckley said sutured IOLs are more controversial because there is no guarantee of how long the sutures will last. Data show that sutured materials may break over time, after about 5 to 7 years. Dr. Wilson said there is a trend shying away from sutured lenses in pediatric patients to provide safer lenses with less frequent dislodging.

Challenges of postop management

“Once the surgery is done, it is not completely done,” Dr. Gold said. “There is a tremendous amount of due diligence and effort that needs to be put forward by the surgeon or the referring physician postoperatively so that parents understand the treatments and the fact that compliance is essential.”

According to Dr. Stahl, one of the biggest challenges is vigilant management of amblyopia with the goal of rehabilitating vision in the operated eye, which may include occlusion therapy and refractive correction after surgery. Additionally, there may be an increased risk for glaucoma postoperatively.

“Probably as many as 30% of children who have surgery who are less than 2 months of age will develop glaucoma when they are older,” Dr. Lambert said.

Physicians should carefully monitor corneal size and clarity, changes in refractive error, optic nerve cupping and IOP to help to identify glaucoma early and prevent vision loss with treatment, Dr. Stahl suggested.

In addition, children tend to have an aggressive healing response, leading to a risk of postoperative inflammation. The surgeon needs to monitor the patient carefully and titrate steroid doses accordingly. Dr. Stahl said that it is not unusual to use oral steroids in addition to topical steroids in a child after cataract surgery. – by Tara Grassia

Lindstrom's Perspective
Evaluations continue in many areas of pediatric cataract surgery

Taking into consideration the increased risk for development of glaucoma after early extraction of congenital cataracts, do you recommend performing this surgery before 4 weeks of life or after?

References:

• Dave H, Phoenix V, Becker ER, Lambert SR. Simultaneous vs. sequential bilateral cataract surgery for infants with congenital cataracts: Visual outcomes, adverse events, and economic costs. Arch Ophthalmol. 2010;128(8):1050-1054.
• Infant Aphakia Treatment Study Group. A randomized clinical trial comparing contact lens with intraocular lens correction of monocular aphakia during infancy: grating acuity and adverse events at age 1 year. Arch Ophthalmol. 2010;128(7):810-818.
• Infant Aphakia Treatment Study Group. The infant aphakia treatment study: design and clinical measures at enrollment. Arch Ophthalmol. 2010;128(1):21-27.
• Kushner BJ. Simultaneous cataract surgery for bilateral congenital cataracts: are the cost savings worth the risk? Arch Ophthalmol. 2010;128(8):1073-1074.
• Lin AA, Buckley EG. Update on pediatric cataract surgery and intraocular lens implantation. Curr Opin Ophthalmol. 2010;21(1):55-59.
• Plager DA, Carter BC. Pediatric cataracts. Focal Points. 2011;29(2).

• Edward G. Buckley, MD, can be reached at Duke University School of Medicine, P.O. Box 3802, Duke University Eye Center, Durham, NC 27710; 919-684-3957; fax: 919-684-6096; e-mail: buckl002@mc.duke.edu.
• Robert S. Gold, MD, can be reached at Adult Eye Muscle Disorders Eye Physicians of Central Florida, 225 W. State Road 434, Suite 111, Longwood, FL 32750; 407-767-6411; fax: 407-767-8160; e-mail: RSGEye@aol.com.
• Scott R. Lambert, MD, can be reached at Emory University, 1365-B Clifton Road, Atlanta, GA 30322; 404-778-4417; fax 404-778-5203; e-mail: scott.lambert@emory.edu.
• David A. Plager, MD, can be reached at Indiana University Medical Center, 702 Rotary Circle Indianapolis, IN 46202; 317-274-1214; e-mail: dplager@iupui.edu.
• Erin D. Stahl, MD, can be reached at Children’s Mercy Hospital, 2401 Gillham Road, Kansas City, MO 64108; 816-234-3046; fax: 816-855-1793; e-mail: edstahl@cmh.edu.
• M. Edward Wilson, MD, can be reached at Albert Florens Storm Eye Institute at the Medical University of South Carolina, 167 Ashley Ave., Charleston, SC 29425; 843-792-7622; fax: 843-792-1166; e-mail: wilsonme@musc.edu.
• Disclosures: Drs. Buckley, Gold, Plager and Stahl have no relevant financial disclosures. Dr. Lambert has a grant from the NIH, is a consultant for Bausch + Lomb, is a participant in a clinical trial with Alcon, and is on the advisory board for Lions International. Dr. Wilson is a consultant for Bausch + Lomb and Alcon. He receives book royalties from Springer.