Charleston, SC-IOL insertion is the standard of care afteruncomplicated cataract surgery for children beyond infancy, despitethe fact that these implantations are still considered off-labelprocedures. Lens implantation is also an acceptable alternative forinfants, especially those without complex microphthalmia.
Charleston, SC-IOL insertion is the standard of care after uncomplicated cataract surgery for children beyond infancy, despite the fact that these implantations are still considered off-label procedures. Lens implantation is also an acceptable alternative for infants, especially those without complex microphthalmia.
"There are no absolute contraindications for IOL implantation in children, but there are some relative contraindications or some areas where further study is still needed, and this would include active uveitis, the absence of capsular support, complex microphthalmia, and even infancy," said M. Edward Wilson Jr., MD, professor and chairman of ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston.
Despite controversy about whether to implant IOLs in the first year of life, a survey conducted several years ago revealed that this procedure is being performed more than ever. Results of the 2001 worldwide survey of American Society of Cataract and Refractive Surgery members that was conducted by Dr. Wilson showed that 29% of respondents who offer pediatric surgery had implanted IOLs in children during the first year of life, as had 38% of respondents who belonged to the American Association for Pediatric Ophthalmology and Strabismus.
A randomized clinical trial, the Infant Aphakia Treatment Study (IATS), is under way in 12 centers throughout the United States. Funded by the National Eye Institute, the study is comparing primary implantation with primary aphakia for cataracts removed in the first 6 months of life. Infants born with a cataract in one eye and operated on at ages 4 weeks to 7 months are being randomly assigned to cataract removal and IOL implantation, with glasses for residual hyperopia, or cataract removal and a contact lens. The study began in December 2004, and approximately 30 children have been enrolled.
"The IATS will also collect some very informative data on amblyopia treatment and parental stress, so I think we will get some very important information from it, not just about IOLs," Dr. Wilson said.
The AcrySof Natural (Alcon Laboratories), a single-piece acrylic lens, is the IOL chosen for the IATS.
"We found that in small capsular bags, it really is a surgeon-friendly lens," Dr. Wilson said. "Although it is 13 mm in overall diameter, it fits well into the capsular bag. We have found that even in small capsular bags, it conforms well and does not end up being crimped by the capsular fibrosis."
The three-piece AcrySof IOL is also popular for implantation in infants, but stretching of the capsulorhexis and capsular bag can be a problem, Dr. Wilson said.
Among surgeons who perform congenital cataract surgery, the majority preferred acrylic IOLs, according to the same 2001 survey that asked about experience with lens implantation. Eighty-four percent of the respondents routinely used acrylic IOLs in children, 28% used PMMA lenses, and 5% used silicone IOLs (multiple responses were allowed). The surveyed surgeons also preferred hydrophobic acrylic lenses to hydrophilic acrylic IOLs by a margin of 38 to 1.
At the time of the survey, only 4% of the respondents reported using heparin-surfaced PMMA lenses despite the fact that they have been shown to be more biocompatible than unmodified PMMA lenses, Dr. Wilson said.
"There are many high-quality IOLs to choose from," he added, noting that most high-quality lenses used in adults will also perform well in children. The AcrySof series of IOLs, and other acrylic models such as the Tecnis and the Sensor, appear to be the most commonly used in children, although modern, third-generation silicone lenses also produce good results.
The AcrySof IOLs are available in both SA60 and SA30 series; the SA60, a single-piece acrylic with a 6-mm optic, is used most often, according to Dr. Wilson.
"This lens does not have any posterior angulation and should be used for capsule fixation only and not in the sulcus," Dr. Wilson said. The SN60 adds a blue-blocker lens.
The three-piece MA60 has an acrylic optic and PMMA haptics and is posterior angulated so it is acceptable for both capsule fixation and the sulcus.