Measurement agreement between a new biometer based on partial coherence interferometry and a validated biometer based on optical low-coherence reflectometry

J Cataract Refract Surg. 2016 Jan;42(1):68-75. doi: 10.1016/j.jcrs.2015.05.042.


Purpose: To evaluate the agreement of ocular measurements obtained with a new optical biometer (AL-Scan) and a previously validated optical biometer (Lenstar).

Setting: Eye Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.

Design: Prospective observational cross-sectional study.

Methods: For a comprehensive comparison between the partial coherence interferometry (PCI) device and the optical low-coherence reflectometry (OLCR) device, the axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), aqueous depth, mean keratometry (K), astigmatism, white-to-white (WTW), and pupil diameter were measured 3 times per device in eyes with cataract. The sequence of the device was in random order. The mean values were compared and 95% limits of agreement (LoA) were assessed.

Results: Ninety-two eyes of 92 cataract patients were included. Bland-Altman analysis showed excellent agreement between the PCI device and the OLCR device for AL, CCT, ACD and aqueous depth measurements with narrow 95% LoA (-0.05 to 0.06 mm, -13.39 to 15.61 μm, -0.11 to 0.10 mm, and -0.12 to 0.10 mm, respectively), and the P values were more than 0.05. The mean K, astigmatism, and WTW values provided by the PCI device were in good agreement with the OLCR device, although statistically significant differences were detected. A major difference was observed in the pupil diameter measurement, with a 95% LoA of -0.73 to 1.21 mm.

Conclusions: The PCI device biometer provided ocular measurements similar to those provided by the OLCR device for most parameters, especially for AL, CCT, and ACD. The pupil diameter values obtained with the PCI device were in poor agreement with the OLCR device, and these measurements should be interpreted with necessary adjustment.

Financial disclosure: None of the authors has a proprietary or financial interest in any material or method mentioned.

Publication types

  • Comparative Study
  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Anterior Chamber / pathology*
  • Aqueous Humor
  • Axial Length, Eye / pathology*
  • Biometry / instrumentation*
  • Cataract / pathology
  • Cornea / pathology*
  • Cross-Sectional Studies
  • Female
  • Humans
  • Interferometry / instrumentation
  • Light
  • Male
  • Middle Aged
  • Prospective Studies
  • Reproducibility of Results