Comparison of an image-guided system with four other devices for planning precise toric intraocular lens power calculation and axis alignment.

PURPOSE: To compare astigmatism and other keratometric parameters obtained with IOLMaster 500/700, Pentacam HR/AXL, and the VERION Image-Guided System.

SETTING

Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany.

DESIGN

Retrospective, comparative clinical study.

METHODS

1107 eyes of 654 patients were examined. The outcome parameters analyzed included the horizontal corneal diameter (white-to-white [WTW]), flattest (K1) and steepest keratometry (K2), axis values (K1 and K2 axis), astigmatism, and axis of astigmatism (axis). These parameters were compared between devices using the Bland-Altman method.

RESULTS

There was no significant difference between the VERION and the IOLMaster 500/700 in corneal astigmatism measurements ( P > .05). The astigmatism measurements with the Pentacam HR/AXL showed a statistically significant difference compared with the VERION Image-Guided System. The astigmatism measured with the VERION Image-Guided System was -0.04 ± 0.38 mm smaller ( P = .037) when compared with the Pentacam HR and -0.07 ± 0.37 mm smaller ( P < .001) than with the Pentacam AXL. The measurements of the astigmatic axis, as well as the K1 axis and the K2 axis showed a high agreement for all devices ( P > .05). However, significant differences were found between the devices for the WTW, K1, and K2 measurements ( P < .05).

CONCLUSIONS

The astigmatism measured by the VERION Image-Guided System is comparable with the measurements obtained by IOLMaster 500/700 and Pentacam HR/AXL, allowing the devices to be used interchangeably when planning astigmatism correction during cataract and refractive surgery. By limiting the use to measurements in clinic with "green" quality rating, a high agreement for all variables between the VERION Image-Guided System and IOLMaster 500/700 can be achieved.