H John Shammas1, Steven Chan. 1. Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA. jshammas@shammaseye.com
Abstract
PURPOSE: To evaluate the precision of the axial length (AL), keratometry (K), anterior chamber depth (ACD), astigmatism, and minus astigmatic cylinder axis measurements by a partial coherence interferometry (PCI)-keratometry device. SETTING: Private practice, Lynwood, California. METHODS: This prospective comparative observational study analyzed measurements in the second eye to have cataract surgery. Before surgery in the first eye, AL, K, ACD, astigmatism, and cylinder axis in both eyes were measured with an IOLMaster PCI device. The measurements were repeated approximately 1 month later, before second eye-surgery. The 2 sets of measurements were compared. RESULTS: The study evaluated 121 eyes of 121 patients. The interclass correlation coefficient (ICC) for AL was 0.999 in all 3 signal-to-noise ratio (SNR) categories; the highest difference range was with an SNR below 100. Astigmatism, K, and cylinder axis had a high correlation in flat corneas (K reading <42.0 diopters [D]) (ICC = 0.994, 0.978, and 0.918, respectively) and a poorer correlation with K readings between 42.0 D and 44.0 D (ICC = 0.905, 0.774, and 0.456, respectively) and K readings above 44.0 D (ICC = 0.988, 0.729 and 0.446, respectively). CONCLUSIONS: The precision of the PCI measurements was extremely high for AL with low fluctuations (95% limits of agreement [LoA], 0.06 mm) and was relatively high for K readings with higher fluctuations (95% LoA, 0.55 D) and for ACD (95% LoA, 0.2 mm). The precision of astigmatism and cylinder axis was high in flat corneas and relatively low in steeper corneas. Copyright (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
PURPOSE: To evaluate the precision of the axial length (AL), keratometry (K), anterior chamber depth (ACD), astigmatism, and minus astigmatic cylinder axis measurements by a partial coherence interferometry (PCI)-keratometry device. SETTING: Private practice, Lynwood, California. METHODS: This prospective comparative observational study analyzed measurements in the second eye to have cataract surgery. Before surgery in the first eye, AL, K, ACD, astigmatism, and cylinder axis in both eyes were measured with an IOLMaster PCI device. The measurements were repeated approximately 1 month later, before second eye-surgery. The 2 sets of measurements were compared. RESULTS: The study evaluated 121 eyes of 121 patients. The interclass correlation coefficient (ICC) for AL was 0.999 in all 3 signal-to-noise ratio (SNR) categories; the highest difference range was with an SNR below 100. Astigmatism, K, and cylinder axis had a high correlation in flat corneas (K reading <42.0 diopters [D]) (ICC = 0.994, 0.978, and 0.918, respectively) and a poorer correlation with K readings between 42.0 D and 44.0 D (ICC = 0.905, 0.774, and 0.456, respectively) and K readings above 44.0 D (ICC = 0.988, 0.729 and 0.446, respectively). CONCLUSIONS: The precision of the PCI measurements was extremely high for AL with low fluctuations (95% limits of agreement [LoA], 0.06 mm) and was relatively high for K readings with higher fluctuations (95% LoA, 0.55 D) and for ACD (95% LoA, 0.2 mm). The precision of astigmatism and cylinder axis was high in flat corneas and relatively low in steeper corneas. Copyright (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.
Authors: Alicia Galindo-Ferreiro; Julita De Miguel-Gutierrez; Manuel González-Sagrado; Alberto Galvez-Ruiz; Rajiv Khandekar; Silvana Schellini; Julio Galindo-Alonso Journal: Int J Ophthalmol Date: 2017-09-18 Impact factor: 1.779
Authors: Marcus Ang; Damien Gatinel; Dan Z Reinstein; Erik Mertens; Jorge L Alió Del Barrio; Jorge L Alió Journal: Eye (Lond) Date: 2020-07-24 Impact factor: 3.775