Ray tracing optimization: a new method for intraocular lens power calculation in regular and irregular corneas
Pablo Pérez-Merino1, Jaime Aramberri2,3, Andrés Vásquez Quintero4
1Centre for Microsystems Technology, Ghent University and Imec, Technologiepark 126, 9052, Ghent, Belgium. pablo.perezmerino@ugent.be.
Scientific Reports
|March 21, 2023
Summary
A new ray tracing algorithm improves intraocular lens (IOL) power calculation accuracy, especially for eyes with higher-order aberrations (HOAs). This method optimizes visual performance by adjusting targets, outperforming traditional calculations in complex cases.
Area of Science:
- Ophthalmology
- Optical Engineering
- Computational Vision
Background:
- Accurate intraocular lens (IOL) power calculation is crucial for refractive outcomes after cataract surgery.
- Traditional methods may struggle with eyes exhibiting higher-order aberrations (HOAs) and astigmatism, potentially leading to suboptimal visual results.
- Keratoconus and other corneal irregularities significantly impact visual quality and necessitate advanced calculation approaches.
Purpose of the Study:
- To develop and validate a novel algorithm for precise IOL power calculation using ray tracing and simulated visual performance.
- To optimize through-focus visual targets by integrating natural corneal HOAs and sphero-cylindrical corrections.
- To compare the accuracy of the novel Ray Tracing Optimization (RTO) algorithm against the SRK/T formula in diverse eye models.
Main Methods:
- Custom algorithms for ray tracing optimization (RTO) were developed and applied to 210 statistical eye models simulating keratoconus progression.
- The study incorporated natural corneal HOAs and sphero-cylindrical corrections, analyzing defocus and astigmatism for maximum Visual Strehl.
- IOL power calculations from the RTO method were compared with the SRK/T formula, assessing agreement within ±0.50D.
Main Results:
- The RTO algorithm showed high agreement (91.66%) with SRK/T for eyes with low HOAs, achieving near-neutral defocus and astigmatism targets.
- For eyes with higher HOAs (24-120 months), RTO demonstrated significant visual improvement potential with optimized targets.
- Discrepancies exceeding ±0.50D occurred in 81.95% of high HOA cases, with power differences over 3D in 42.2% and cylinder adjustments over 3D in 18.4%.
Conclusions:
- The novel RTO algorithm offers enhanced accuracy for IOL power calculation, particularly in eyes with significant corneal HOAs.
- Optimizing the refractive target based on simulated visual performance and HOAs is critical for improving outcomes in complex eyes.
- Favorable interactions between lower and higher-order aberrations can influence visual performance, necessitating adaptive refractive targets for IOL power calculation.
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