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Intraocular lenses for pediatric implantation: biomaterials, designs, and sizing
M E Wilson1, D J Apple, E C Bluestein
1N. Edgar Miles Center for Pediatric Ophthalmology, Storm Eye Institute, Medical University of South Carolina, Charleston 29425-2236.
Insights
Pediatric intraocular lenses (IOLs) require specific sizing for children under two years old. Downsized 10.0 mm IOLs are recommended for this age group, with standard sizes suitable for older children.
Area of Science:
- Ophthalmology
- Biomedical Engineering
- Pediatric Medicine
Background:
- Posterior chamber intraocular lenses (IOLs) are increasingly used in pediatric patients.
- Current IOLs are designed for adults, posing challenges for implantation in smaller pediatric eyes.
- Pediatric crystalline lens size and capsular bag dimensions differ significantly from adults.
Purpose of the Study:
- To determine appropriate biomaterials, designs, and sizes for pediatric intraocular lenses (IOLs).
- To establish a growth curve for the pediatric crystalline lens.
- To inform the development and clinical trials of specialized pediatric IOLs.
Main Methods:
- Postmortem analysis of 50 pediatric eyes to estimate crystalline lens growth.
- Miyake posterior view analysis of standard and prototype intraocular lenses (IOLs) implanted in pediatric eyes.
- Development of a crystalline lens growth curve from birth to 16 years.
Main Results:
- Ninety percent of crystalline lens growth occurs within the first two years of life.
- Downsized capsular IOLs (approx. 10.0 mm diameter) are suitable for children under two years.
- Standard 12.0 mm to 12.5 mm capsular IOLs are appropriate for children over two years old.
Conclusions:
- Clinical trials for downsized (10.0 mm) capsular IOLs are warranted for infants and toddlers.
- IOL downsizing is generally not necessary after age two, barring unusually small eye dimensions.
- Standard IOL sizes may be safely implanted in older children, potentially avoiding future lens exchange.
Abstract:
Posterior chamber intraocular lenses (IOLs) are being implanted in children with increasing frequency. However, with rare exceptions, only IOLs designed for adults are currently available. These lenses may be difficult to insert into small eyes. Since the pediatric crystalline lens is smaller than that of adults and because the capsular bag does not continue to grow after lensectomy, it is worthwhile to determine the biomaterials, designs, and sizes that may be appropriate for pediatric implantation. In a study of 50 pediatric eyes obtained postmortem, we have documented an estimated growth curve for the developing crystalline lens between birth and 16 years of age. Ninety percent of crystalline lens growth occurs during the first two years of life. Based on these data and this study using the Miyake posterior view analysis of implanted standard and prototype IOLs, we recommend the following: Clinical trials of capsular IOLs, downsized to approximately 10.0 mm diameter, are appropriate for children under two years of age. Capsular IOLs are defined as flexible open-loop, one-piece, all poly(methyl methacrylate), modified C-loop designs made specifically for in-the-bag placement. Because the rapid growth phase of the lens is complete by the age of two, we believe that downsizing the IOL is not necessary after this age unless axial length measurements indicate an unusually small eye. Standard flexible 12.0 mm to 12.5 mm diameter capsular IOLs can be safely implanted. Such lenses could be tolerated throughout life, obviating the need for later IOL exchange.