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Christoph Lwowski1, Klemens Paul Kaiser2, Yaroslava Wenner2
1Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. lwowski@med.uni-frankfurt.de.
Insights
A new aphakic Contact Lens (aCL) formula accurately calculates contact lens power in infants. This formula is reliable and comparable to retinoscopy, outperforming other methods.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Biomedical Engineering
Background:
- Aphakia in infants presents unique challenges for refractive correction.
- Accurate contact lens power calculation is crucial for visual development in pediatric aphakia.
Purpose of the Study:
- To develop and validate the aphakic Contact Lens (aCL) formula for calculating contact lens power in aphakic infants.
- To assess the predictive performance of the aCL formula using preoperative data.
Main Methods:
- A retrospective, two-center study developed and optimized the aCL formula using a development cohort.
- The formula's predictive accuracy was validated against retinoscopy, the Trivedi and Wilson (TW) formula, and a +32.0 D contact lens.
- Performance metrics included prediction error (PE) and absolute prediction error (AE).
Main Results:
- The aCL formula showed comparable median absolute prediction errors to retinoscopy (0.53 D vs. 0.69 D).
- It significantly outperformed the TW formula (3.25 D) and the +32.0 D contact lens (2.63 D).
- The aCL formula achieved better accuracy within ±2.0 D compared to retinoscopy (83.3% vs. 72.2%).
Conclusions:
- The aCL formula is a reliable and accurate tool for contact lens power calculation in aphakic infants.
- It demonstrates superior performance compared to existing formula-based and default strategies.
- Further validation in larger cohorts is recommended.
Purpose:
To develop and test a formula for contact lens calculation in aphakic infants. This formula, termed the "aphakic Contact Lens" (aCL) formula, utilizes preoperative axial length and keratometry data.
Methods:
This retrospective, consecutive, two-center study used data derived from a development cohort (Freiburg, Germany) to create and optimize the aCL formula in aphakic eyes. A separate validation cohort (Frankfurt, Germany) was used to validate its predictive performance. The accuracy of the aCL formula was compared against: retinoscopy, a previously reported formula (Trivedi and Wilson, TW), and the use of a + 32.0 diopter (D) CL. Performance was evaluated using the prediction error (PE), absolute prediction error (AE) and the number of eyes within a certain range from retinoscopy (± 0.5D, ± 1.0D, ± 2.0D).
Results:
The aCL formula demonstrated comparable absolute prediction errors to retinoscopy (median AE 0.53D vs. 0.69D) and outperforms the TW formula or + 32D CL (median AE 3.25D and 2.63D). The number of eyes within ± 0.5D (38.3%) is lower compared to retinoscopy (50.0%), but comparable for ± 1.0D and better for ± 2.0D (61.7% vs. 66.7%, 83.3% vs. 72.2%). Both perform better than TW formula and + 32.0D (ranging from 0.0% for ± 0.5D to 33.3% for ± 2.0D).
Conclusions:
The aCL formula is a reliable and accurate tool for determining CL power in aphakic infants. It performed superior to other formula-based and default strategies and is comparable to a retinoscopy. Still, follow-up studies with larger cohorts are needed to validate this outcome.
