Repeatability of posterior and total corneal curvature measurements with a dual Scheimpflug-Placido tomographer

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• 作者：Eric J. Kim ; BSAuthor Vitae ; Ildamaris Montes de Oca ; MD ; Li Wang ; MD ; PhD ; Mitchell P. Weikert ; MD ; Douglas D. Koch ; MD ; Sumitra S. Khandelwal ; MD ; ^{sumitra.khandelwal@bcm.edu" class="auth_mail" title="E-mail the corresponding author}
• 刊名：Journal of Cataract & Refractive Surgery
• 出版年：2015
• 出版时间：December 2015
• 年：2015
• 卷：41
• 期：12
• 页码：2731-2738
• 全文大小：1222 K

文摘

To evaluate the repeatability of the Galilei G4 dual Scheimpflug analyzer in measuring simulated keratometric, total, and posterior corneal curvature in normal and post-refractive surgery eyes.

Setting

Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.

Design

Prospective evaluation of diagnostic technology.

Methods

A single observer performed 3 consecutive measurements in 1 eye of each subject. The following were evaluated in both eyes and in eyes that had previous myopic excimer-laser surgery: (1) simulated keratometric corneal power and astigmatism, (2) total corneal power and astigmatism, and (3) posterior corneal power and astigmatism. Repeatability was assessed by calculating the within-subject standard deviation (S_w), coefficient of variation (CoV), and intra-class correlation coefficient (ICC).

Results

The study evaluated 41 normal eyes and 36 post-refractive surgery eyes. In normal eyes, the S_w was 0.08 diopters (D), 0.10 D, and 0.03 D for simulated keratometric, total, and posterior corneal power, respectively. The CoV ranged from 0.16% to 0.40%, and the ICC was 0.992 or more (P < .001) for all corneal powers. In post-refractive surgery eyes, the S_w was 0.09 D, 0.09 D, and 0.02 D for simulated keratometric, total, and posterior corneal power, respectively. The CoV ranged from 0.19% to 0.32%, and the ICC was 0.990 or more (P < .001) for all corneal powers. For posterior corneal astigmatism, the ICC was 0.814 and 0.886 for normal and post-refractive surgery eyes, respectively.

Conclusions

In normal corneas and corneas that had undergone myopic excimer laser ablation, the dual Scheimpflug analyzer showed high intra-observer repeatability for simulated keratometric, total, and posterior corneal power measurements and moderate repeatability for posterior corneal astigmatism.

Financial Disclosure

Drs. Koch, Weikert, and Wang received research support from Ziemer USA, Inc. No other author has a financial or proprietary interest in any material or method mentioned.