Comparison of 2 laser instruments for measuring axial length

Kenneth J. Hoffer, H. John Shammas, Giacomo Savini

Research output: Contribution to journalArticlepeer-review


Purpose: To compare axial length (AL), anterior chamber depth (ACD), and keratometric (K) measurements of 2 laser biometers. Setting: Private practices, Lynwood and Santa Monica, California, USA. Methods: In this prospective comparative observational study of eyes with cataract and eyes with a clear lens, AL, ACD, and K measurements were performed using an IOLMaster biometer, which uses partial coherence interferometry (PCI), and a Lenstar LS 900 biometer, which uses optical low-coherence reflectometry (OLCR). Intraocular lens (IOL) power calculation was performed using the Haigis formula. The IOL prediction error was calculated for each eye. Results: The study evaluated 50 eyes with cataract and 50 eyes with a clear lens. There was a good correlation between AL, ACD, and K measurements in the cataractous eyes (r = 0.9993, 0.9667, and 0.9959, respectively) and in eyes with a clear lens (r = 0.9995, 0.8211, and 0.9959, respectively). The OLCR unit measured a slightly longer AL in the cataract group and clear lens group (mean difference 0.026 mm and 0.023 mm, respectively), a deeper ACD (0.128 mm and 0.146 mm, respectively), and a flatter K (-0.107 diopter [D] and -0.121 D, respectively). The differences were statistically significant (P.1). Conclusions: Measurements were comparable between the OLCR device and the PCI device. A slight decrease (0.050) in the a0 constant is recommended if the Haigis formula is used. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Original languageEnglish
Pages (from-to)644-648
Number of pages5
JournalJournal of Cataract and Refractive Surgery
Issue number4
Publication statusPublished - Apr 2010

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Surgery


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