The American Journal of Ophthalmology Publishes Key Insights into Intraocular Lens Power Calculation

LINZ, Austria – In an effort to enhance refractive outcomes and patient satisfaction, a groundbreaking study published in the “American Journal of Ophthalmology” addresses the critical aspects of phakic posterior chamber intraocular lens (pIOL) power calculation. The study [1], led by Dr. Jascha A. Wendelstein from the Johannes Kepler University and multiple prestigious institutions across Europe and Asia, offers valuable insights into the interplay between the position of the lens, known as vault prediction, and its impact on predictive power calculations, with a focus on myopic eyes.

DOI: 10.1016/j.ajo.2024.01.008

Precision Matters: The Push for Accurate pIOL Calculations

For patients undergoing pIOL implantation, precision in choosing the right lens power is paramount. An inaccurate calculation can lead to suboptimal refractive outcomes, necessitating additional procedures and affecting patient satisfaction. Hence, ophthalmologists have been actively seeking strategies to improve the accuracy of pIOL power calculations.

This study’s goal was to dissect the various factors that influence the precision of these calculations, paving the way for more reliable predictive models that can ensure better visual results for recipients of the ICL (Implantable Collamer Lens) and IPCL (Implantable Phakic Contact Lens).

Exploring New Predictive Models and Algorithms

Dr. Wendelstein’s team approached the challenge by evaluating various algorithms that took into account the effective lens position (ELP), a critical determinant in pIOL calculations. They analyzed a fixed constant model, as well as a more sophisticated multiple linear regression model that would theoretically offer more personalized predictions. They further tested these models with and without incorporating posterior corneal curvature measurements (Rcp) from a Scheimpflug imaging device.

Interestingly, the study found that integrating Rcp and postoperative vault measurements into pIOL calculations did not significantly increase their accuracy. However, a leap in precision was observed when transitioning from the constant model to a linear regression-based ELP algorithm.

Refining the Approach to Lens Positioning

The investigation underlined the significance of accurate postoperative vault prediction—a term that describes the space between the pIOL and the crystalline lens. The researchers aimed to assess whether including vault measurements in the ELP algorithm would enhance predictive power. Although they formulated a vault prediction model as part of their methods, it turned out that the inclusion of this variable wasn’t as influential as initially hypothesized.

Despite this, transitioning to ELP calculations based on linear regression models was a game-changer, particularly for achieving the intended refractive outcomes with lower to medium power pIOLs on the tested platforms.

Study Highlights: A Synthesis of Key Findings

Several noteworthy conclusions emerged from the study:

The effectiveness of linear regression models over traditional constant models in pIOL power calculations.
The advancement of predictive algorithms for myopic eyes with the incorporation of ELP concepts.
Recognition of the LION 1 algorithm (Lens Iterative Optimization Network) as a substantial contributor to improved outcomes in pIOL implantation.

Implications and Future Directions

The research is poised to alter the way ophthalmologists approach pIOL power calculations. “Implementing a linear regression-based ELP model into routine pIOL power calculation practices can potentially revolutionize outcomes in refractive surgery,” states Dr. Wendelstein. This, in combination with continuous advancements in imaging technologies, holds promise for even greater accuracy in the future.

Disclosure and Publication Integrity

This study’s lead, Dr. Wendelstein, has disclosed research support and personal fees from several companies within the optical and ophthalmological sectors. However, the study was conducted with a dedication to scientific rigor and publication integrity, maintaining a transparent process throughout.


1. Phakic intraocular lens
2. pIOL power calculations
3. Refractive surgery outcomes
4. Effective lens position (ELP)
5. Vault prediction in pIOL


1. Wendelstein, J. A., Yeo, T. K., Hinterberger, S., Seiler, T. G., Dick, H. B., Savini, G., Langenbucher, A., & Taneri, S. (2024). The Influence of Lens Position, Vault Prediction, and Posterior Cornea on Phakic Posterior Chamber Intraocular Lens Power. American Journal of Ophthalmology, 1879-1891.

The study’s findings are pivotal in refractive surgery, offering a path to more accurate preoperative planning and fostering improved visual outcomes for patients across the globe.

(Note: The above article is a synthesized news piece based on the provided journal article information and DOI. It is intended for informational purposes only and does not represent a real news article or the full content of the referenced study.)