Comparison of Anterior Segment Measurements with Optical Low-coherence Reflectometry and Rotating Dual Scheimpflug Analysis

Purpose: To compare the anterior segment measurements obtained with optical low-coherence reflectometry (OLCR) (Lenstar LS 900, version 2.1.1) and rotating dual Scheimpflug analysis (Galilei G1, version 3).

Setting: Private practice, Policlinic Lleida, Lleida, Spain.

Design: Prospective comparative observational study.

Methods: The following measurements were performed in patients requiring a preoperative study for a refractive procedure or cataract surgery and healthy volunteers from the clinic's staff: central corneal thickness (CCT), anterior chamber depth (ACD), horizontal limbal distance (white-to-white distance [WTW]), pupil diameter, keratometry (K) readings at the steepest meridian (steep K) and the flattest meridian (flat K), corneal astigmatism power, and plus astigmatic cylinder. Measurements were taken using the OLCR device and rotating dual Scheimpflug analyzer. The main outcome measure was the degree of agreement between steep K, flat K, astigmatism power, cylinder axis, CCT, ACD, WTW, and pupil diameter measurements.

Results: The study enrolled 100 eyes of 100 subjects. Steep K, flat K, corneal astigmatism power, cylinder axis, and WTW measurements with the OLCR device and Scheimpflug analyzer showed narrow 95% limits of agreement (LoA), which implies good agreement (P>.05, Bland-Altman plot analysis). In contrast, the range and 95% LoA for CCT, ACD, and pupil diameter values were statistically significantly different (P<.05, Bland-Altman plot analysis).

Conclusion: In clinical practice, the OLCR device and the rotating dual Scheimpflug analyzer system can be used interchangeably for WTW measurements and K readings but not for CCT, ACD, and pupil diameter values.

Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.