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Haptic flexibility affected capsular bag stretch in pediatric cadaver eye study
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Rigid and foldable IOLs designed for adults produce variable degrees of capsulorrhexis ovaling and capsular bag stretch when implanted in pediatric eyes, a study in postmortem eyes found. A one-piece hydrophobic acrylic IOL caused the least capsule stretching in a comparison of six IOL types, researchers said.
Suresh K. Pandey, MD, and colleagues at the Moran Eye Center in Salt Lake City implanted the six types of posterior chamber IOLs into postmortem eyes in two groups: eyes obtained from children less than 2 years of age and eyes obtained from children more than 2 years of age.
The IOL styles included one-piece PMMA, one- and three-piece silicone and one- and three-piece hydrophobic acrylic. The capsulorrhexis and capsular bag diameters were measured before IOL implantation and after in-the-bag IOL fixation with the haptics in the 3-o’clock-to-9-o’clock meridian. The percentage of ovaling of the capsulorrhexis opening was calculated by noting the difference in the opening’s horizontal diameter before and after IOL implantation.
All IOLs produced ovaling of the capsulorrhexis opening and stretching of the capsular bag parallel to the IOL haptics. Significant differences were seen in the amount of capsulorrhexis ovaling and capsular bag stretch between all the IOL types in each group (P < .001).
The difference was only significant between the one-piece hydrophobic acrylic IOL (the Alcon Single-Piece AcrySof) and all other IOLs. This IOL was associated with significantly less capsulorrhexis ovaling and capsular bag stretch in both the younger and older eye groups.
The authors noted that the Single-Piece AcrySof is “easier to insert in a small eye, and the square edge of the three-piece and the single-piece AcrySof IOL optic designs results in delayed posterior capsule opacification … in young eyes.”
There are potential negative consequences when implanting an adult-sized IOL in a pediatric eye, the authors said. These include difficulty in dialing the IOL haptics into the capsular bag and marked capsular bag stretching that can result in posterior capsule folds and striae.
The authors said limitations of the study included minor variations in the IOL optic diameters, which ranged from 5 mm to 6 mm, and in the overall diameters of the IOLs, which ranged from 10.5 mm to 13 mm.
“The sequence of implantation of the six types of IOLs in the same eye may also alter the elasticity of the capsular bag as well as the capsulorrhexis ovaling and capsular bag stretch,” the authors said.
Finally, they said, the long-term consequences after cataract removal and IOL implantation in this population warrants further study.
The study is published in the October issue of Journal of Cataract & Refractive Surgery.