Topography-Guided Refractive Astigmatism Outcomes: Predictions Comparing Three Different Programming Methods

Area of Science:

• Ophthalmology
• Refractive Surgery
• Laser Vision Correction

Background:

• Discrepancies between manifest refraction and topographic measurements of astigmatism can complicate LASIK outcomes.
• Topography-guided LASIK aims to improve refractive accuracy by utilizing detailed corneal mapping.

Purpose of the Study:

• To determine the optimal laser programming strategy for topography-guided LASIK when manifest and topographic astigmatism measurements differ.
• To compare refractive outcomes based on different preoperative data inputs for laser ablation.

Main Methods:

• Retrospective analysis of 52 eyes undergoing topography-guided LASIK with the WaveLight Contoura Vision excimer laser.
• Eyes with significant differences between manifest and topographic cylinder (>0.50D or >10 degrees) were included.
• Vector analysis compared outcomes using manifest refraction, topographic cylinder, and the Phorcides Analytic Engine for laser programming.

Main Results:

• Phorcides provided the best theoretical outcomes (mean error vector: 0.39 ± 0.28 D), followed by topographic cylinder (0.47 ± 0.33 D), and manifest refraction (0.56 ± 0.42 D).
• In cases with low cylinder differences, Phorcides significantly outperformed manifest and topographic cylinder inputs.
• For high cylinder differences, Phorcides showed comparable results to topographic cylinder and outperformed manifest refraction.

Conclusions:

• Topographic measurements or Phorcides-assisted programming lead to more favorable refractive outcomes in topography-guided LASIK compared to manifest refraction.
• These findings support the use of advanced topographic data for optimizing astigmatism correction in LASIK.