Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2015 May;41(5):1018-29.
doi: 10.1016/j.jcrs.2014.08.040.

Comparison of dual rotating Scheimpflug-Placido, swept-source optical coherence tomography, and Placido-scanning-slit systems

Yong Woo Lee  1 , Chul Young Choi  2 , Geun Young Yoon  1
Affiliations
Comparative Study

Comparison of dual rotating Scheimpflug-Placido, swept-source optical coherence tomography, and Placido-scanning-slit systems

Yong Woo Lee et al. J Cataract Refract Surg. 2015 May.

Abstract

Purpose: To compare measurements of corneal indices using dual rotating Scheimpflug-Placido, swept-source optical coherence tomography (OCT), and Placido-scanning-slit systems.

Setting: Kangbuk Samsung Hospital, Seoul, South Korea.

Design: Prospective evaluation of diagnostic tests.

Methods: Corneal topography measurements were performed using dual rotating Scheimpflug-Placido (Galilei G2), swept-source OCT (Casia SS-1000), and Placido-scanning-slit (Orbscan IIz) systems. The intraclass correlation coefficients (ICCs) and Bland-Altman plots were used to evaluate the agreement between measurements.

Results: Fifty post-refractive surgery eyes and 50 normal eyes were evaluated. The agreement in anterior keratometry and pachymetry between the 3 devices was high in both groups (ICC > 0.9). In both groups, the ICC values for posterior keratometry and eccentricity were high between the dual rotating Scheimpflug-Placido and swept-source OCT systems (ICC > 0.9) but not between the Placido-scanning-slit system and the other 2 systems. The Placido-scanning-slit system yielded much steeper values for posterior keratometry in both groups (P < .05). The ICC values for posterior corneal elevation were lower than 0.9 between all 3 devices. The dual rotating Scheimpflug-Placido and swept-source OCT systems showed relatively higher ICC values than the Placido-scanning-slit system in both groups. Maximum posterior elevations were highest with the Placido-scanning-slit system followed by the swept-source OCT system and then the dual rotating Scheimpflug-Placido system.

Conclusions: Anterior keratometry obtained using 3 devices showed high degrees of agreement. Posterior keratometry and eccentricity showed greater agreement between the dual rotating Scheimpflug-Placido and swept-source OCT systems than with the Placido-scanning-slit system. The dual rotating Scheimpflug-Placido and swept-source OCT systems were equivalent in detecting the shape of the cornea and could be considered interchangeable.

PubMed Disclaimer