Comparing the Zeiss Callisto Eye and the Alcon Verion Image Guided System Toric Lens Alignment Technologies.

ABSTRACT

PURPOSE: To compare the alignment meridian generated by the Zeiss Callisto Eye (Carl Zeiss AG, Dublin, CA) and the Alcon Verion Image Guided System (Alcon Laboratories, Inc., Fort Worth, TX). METHODS: In this retrospective comparative evaluation of technology, intraoperative images were captured at different steps in the same surgery, allowing the comparison of the guidance lines generated by the Verion system to the parallel guidance lines generated by the Callisto Eye system. Measurements of each hemi-meridian were quantified using Adobe Photoshop 2015 CC software (Adobe Systems, San Jose, CA). The numbers of degrees separating these alignment meridians were calculated, entered into a database, and analyzed. RESULTS: The authors found that of 98 captured images of 16 eyes, the two technologies were identical in 0 eyes (θ1 = θ2 = 0), similar by 3° in 52 (53%) captured images (θ1 ≠ θ2 ≠ 0), and different by at least 3° in 46 (47%) captured images (θ1 ≠ θ2 ≠ 0). The target meridians were superimposed, the target lines were minimally separated, and the target lines were dissimilar. It was noted that some intraoperative variation occurred from measurement to measurement. Within the small group of 16 cases of routine toric lens implantation in this study, the absolute average number of degrees of misalignment between the Verion and Callisto Eye systems was 3.355 for θ1 and 3.838 for θ2. On average, the intraoperative variation termed "drift" was noted to be 3.963° for θ1, and 4.557° for θ2. CONCLUSIONS: The authors found that small deviations were frequent when comparing two sophisticated technologies. Although deviations greater than 3° occurred in less than 47% of captured images from 16 eyes, smaller but significant variations of less than 3° occurred in 53% of captured images from 16 eyes. It was rare to identify a large deviation. However, the authors identified "drift" in the same eye when measurements were taken at different times. The results indicate that the two systems are not currently interchangeable. Superiority of one system over the other was not determined. [J Refract Surg. 2017;33(7)482-487.].