Relationship Between Intraocular Lens Power and Ocular Refraction Variations.

Objective: To develop a theoretical method to predict the theoretical ratio between changes in intraocular lens (IOL) power (dP) and induced variations in ocular refraction (dR).

Setting: Rothschild Foundation Hospital, Paris, France.

Design: Theoretical study.

Methods: The theoretical changes in dP required for desired variations in dR and influencing variables were computed using a paraxial pseudophakic eye model. This formulation was subsequently validated against the Haigis formula, using half-diopter power increments for comparison. Various eye models, covering a range of axial lengths, keratometry readings, and effective implant positions, were analyzed. Additionally, the impact of keratometry and effective lens position on the IOL power-refraction change ratio was evaluated.

Results: The findings highlight the significant roles of keratometric power and effective lens position in determining the theoretical magnitude of IOL power increment required for a specific dioptric change in refraction. The study extended beyond standard keratometry values to include a wider range of clinical scenarios.

Conclusion: Our model provides theoretical trends for guiding clinicians in predicting the necessary IOL power adjustments for desired refractive changes in pseudophakic eyes.Our work also suggests potential applications in the fine-tuning of adjustable IOLs and more customized IOL power selection for a range of refractive surgeries.