A study comparing methods of optical correction after surgery for congenital cataract shows no difference in visual outcomes or myopic shift between children left aphakic and those who received piggyback IOL implantation.
Reviewed by Mohammad Soleimani, MD
Tehran, Iran-Piggyback IOL implantation is an optically acceptable option for refractive correction after cataract surgery in infants.
However, the approach does not result in better visual outcomes compared with leaving the eye primarily aphakic and using other methods for optical correction.
Furthermore, when the cataract surgery is performed during the first six months of life, piggyback IOL implantation exposes the child to a higher incidence of reoperations for complication management, according to the results of a study conducted by Mohammad Soleimani, MD, assistant professor, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran.
“Optical correction after surgery for congenital cataract remains controversial. The sample size in our study was small and so it was not adequately powered to rule out a difference in visual outcomes between groups if it does exist,” Dr. Soleimani said. “Therefore, studies including a larger population are needed to confirm or reject our findings.”
Dr. Soleimani and colleagues at the Farabi Eye Hospital, Tehran University of Medical Sciences, undertook a comparative study to evaluate the long-term efficacy and safety of piggyback IOL implantation versus aphakia for infantile cataract.
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It included infants operated on between 1998 and 2007. There were 23 eyes of 14 infants that received a piggyback IOL and 32 eyes of 20 infants left aphakic after the cataract surgery.
“The findings of our study do favor leaving the eye aphakic,” he said. “In practice, however, it is important to individualize the decision by taking into account parental compliance with contact lens wear or spectacles that is critical for a good visual outcome.”
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In the piggyback IOL group, a permanent posterior IOL was implanted in the capsular bag at the time of cataract surgery and a second temporary IOL was placed in the ciliary sulcus with the plan to explant the sulcus IOL later in life to compensate for changing refraction. In the aphakic group, optical correction was provided with contact lenses, spectacles, or secondary IOL implantation.
The mean age at the time of cataract surgery was seven and a half months for the piggyback IOL group and six months for the aphakic group. The difference between groups was not statistically significant.
Mean follow-up in the piggyback IOL and aphakic groups was 6.2 years and 5.8 years, respectively, and at last follow-up median logMAR visual acuity in the piggyback IOL and aphakia groups was 0.85 and 0.89, respectively (p > 0.05).
“In further analyses we found a positive relationship between age at the time of surgery and visual acuity at last follow-up in the aphakic group but not in the piggyback IOL group,” Dr. Soleimani reported.
Mean myopic shift at one year after surgery was also similar in the piggyback IOL and aphakic groups with -5.28 and -5.10 D, respectively.
“Previous studies report a significantly greater myopic shift in pseudophakic versus aphakic eyes,” Dr. Soleimani said. “The lack of difference between groups in our study may be explained by the effect of the piggyback IOL pushing on the posterior lens.”
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The safety review showed that the rate of reoperations due to complications was three-fold and significantly higher in the eyes that received a piggyback IOL than in the aphakic group (48% versus 16%).
However, when the analysis was restricted to children who underwent cataract surgery when they were older than six months, the rate of reoperations for complications was lower in both groups and no longer significantly different between groups.
Mohammad Soleimani, MD
This article was adapted from Dr. Soleimani’s presentation at the 2015 meeting of the American Society of Cataract and Refractive Surgery. An article reporting on the study is in press in the Middle East African Journal of Ophthalmology. Dr. Soleimani has no relevant financial interests to disclose.