Accuracy, repeatability, and reproducibility of Artemis very high-frequency digital ultrasound arc-scan lateral dimension measurements

Abstract

Purpose-To determine the accuracy, repeatability, and reproducibility of measurement of lateral dimensions using the Artemis (Ultralink LLC) very high-frequency (VHF) digital ultrasound (US) arc scanner. Setting-London Vision Clinic, London, United Kingdom.Methods-A test object was measured first with a micrometer and then with the Artemis arc scanner. Five sets of 10 consecutive B-scans of the test object were performed with the scanner. The test object was removed from the system between each scan set. One expert observer and one newly trained observer separately measured the lateral dimension of the test object. Two-factor analysis of variance was performed. The accuracy was calculated as the average bias of the scan set averages. The repeatability and reproducibility coefficients were calculated. The coefficient of variation (CV) was calculated for repeatability and reproducibility.Results-The test object was measured to be 10.80 mm wide. The mean lateral dimension bias was 0.00 mm. The repeatability coefficient was 0.114 mm. The reproducibility coefficient was 0.026 mm. The repeatability CV was 0.38%, and the reproducibility CV was 0.09%. There was no statistically significant variation between observers (P = .0965). There was a statistically significant variation between scan sets (P = .0036) attributed to minor vertical changes in the alignment of the test object between consecutive scan sets. Conclusion-TheArtemis VHF digital US arc scanner obtained accurate, repeatable, and reproducible measurements of lateral dimensions of the size commonly found in the anterior segment.Anterior segment dimensions such as angle-to-angle or sulcus-to-sulcus diameters apply directly to the sizing of intraocular lenses (IOLs). Accurate determination of these lateral anterior segment dimensions is a key factor in the safety of these devices.The sulcus-to-sulcus width has to date only been estimated from the horizontal corneal diameter (white-to-white) obtained externally. Some surgeons use the white-to-white measurement, and NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript others size the IOL by adding 0.5 to 1.0 mm to the white-to-white measurement. 1 However, published studies have not found a significant anatomical correlation between white-to-white and sulcus-to-sulcus measurements. 2-4 It appears, therefore, that estimating sulcus-to-sulcus from the white-to-white diameter could be responsible for the occasional sizing issues observed. 1The Artemis very high-frequency (VHF) digital ultrasound (US) arc scanner (Ultralink LLC) can image the anterior segment, providing measurement of intraocular dimensions such as the angle-to-angle width, sulcus-to-sulcus width, and anterior chamber depth. 1,2,5,6 The aim of this study was to determine the accuracy, repeatability, and reproducibility of lateral dimensions similar in magnitude to those found in the anterior segment with the Artemis VHF digital US arc scanner. Materials and MethodsThis prospective study was designed to quantify the accura...

Correlation of Anterior Chamber Angle and Ciliary Sulcus Diameters With White-to-White Corneal Diameter in High Myopes Using Artemis VHF Digital Ultrasound

“…The within-eye standard deviation for both angle diameter (0.13 mm) and sulcus diameter (0.23 mm) was higher than that which we reported when measuring an inanimate test object (0.04 mm) using the same scanner that was used for the present study 25. Although every effort was made to obtain scans in the same horizontal meridian, this variability is likely due to slight variation in the scan plane between scans and measurement error caused by observer judgment of the fiducial points.…”

“…The Artemis 1 VHF digital ultrasound arc-scanner has previously been shown to obtain measurements on a test object with lateral dimensions of the size commonly found in the anterior segment with accuracy of 0.00 mm, repeatability of 0.04 mm, and reproducibility of 0.01 mm 25. We set out to investigate the accuracy of estimating angle diameter and sulcus diameter from external measurements by analyzing the direct correlations between white-to-white, angle diameter, and sulcus diameter as well as multivariate correlations including other conventional external measurements—manifest refraction, ACD, corneal curvature, central corneal thickness (CCT), and age.…”

Meridional differences in internal dimensions of the anterior segment in human eyes evaluated with 2 imaging systems

“…Indeed, Characteristics such as accuracy, repeatability, reproducibility, and axial and lateral resolution of both technologies have been reported in previous studies. [14][15][16][17][18][19][20][21][22][23][24][25][26] We used the same basic study protocol in the autopsy eyes and clinical studies reported here and found that the internal dimensions of the anterior segment of the human eye varied significantly between the 4 meridians considered, regardless of the technology, observer, or eye series.…”

“…Very high frequency ultrasonography (VHF US), [14][15][16][17][18] and anterior segment optical coherence tomography (AS-OCT) [19][20][21][22][23][24][25][26] represent promising technologies for noninvasive imaging of the anterior segment of the eye. The aim of this study was to determine whether internal dimensions of the anterior segment of the human eye, such as angle-to-angle (A-A) and sulcus-to-sulcus (S-S) dimensions, are significantly different along 4 different meridians.…”

Repeatability of Layered Corneal Pachymetry with the Artemis Very High-Frequency Digital Ultrasound Arc-Scanner

“…The Artemis 1 has been used to measure flap thickness reproducibility 22,23 ; provide diagnoses for optical complications after corneal refractive surgery 24-26 ; demonstrate epithelial changes after myopic LASIK, 27 hyperopic LASIK, 28 and orthokeratology 29 ; investigate the sizing issues related to phakic intraocular lenses (IOLs) 30-33 ; measurement of stromal change to evaluate excimer laser ablation depth 34 ; describe the epithelial thickness 35 and stromal thickness 36 in a normal population; describe corneal, epithelial, and stromal thickness in a keratoconic population 37 ; and using epithelial thickness profiles to screen for keratoconus. 38,39 The Artemis 1 prototype was used for the present study.…”