Aberration-guided Intraocular Lens Power Calculation in Keratoconus: Ray Tracing Optimization

Area of Science:

• Ophthalmology
• Optical Engineering
• Biomedical Engineering

Background:

• Keratoconus presents unique challenges for cataract surgery due to corneal irregularities.
• Accurate prediction of postoperative refractive error is crucial for visual outcomes in these patients.

Purpose of the Study:

• To evaluate the predictive accuracy of ray tracing optimization (RTO) for postoperative refractive error in eyes with both keratoconus and cataracts.
• To assess the impact of higher-order aberrations on RTO accuracy.

Main Methods:

• A case series involving 22 keratoconic eyes undergoing cataract surgery.
• Patient-specific eye models were created using corneal Zernike coefficients and IOL geometry.
• Ray tracing optimization (RTO) algorithms predicted refraction, compared with postoperative subjective refraction using power vectors (SEQ, J0, J45).

Main Results:

• Ray tracing optimization (RTO) demonstrated good agreement with postoperative subjective refraction.
• Prediction accuracy within ±0.5D was 68.2% for SEQ and J0, and 59.1% for J45.
• Accuracy was highest in eyes with predominant vertical coma (Z3-1) as a higher-order aberration.

Conclusions:

• Aberration-guided RTO offers accurate refractive predictions for keratoconic eyes undergoing cataract surgery.
• Incorporating measured higher-order aberrations, particularly vertical coma, enhances IOL power selection accuracy.