Repeatability and interobserver reproducibility of Artemis-2 high-frequency ultrasound in determination of human corneal thickness

Abstract

BackgroundThe purpose of this study was to assess the repeatability and limits of agreement of corneal thickness values measured by a high-frequency ultrasound (Artemis-2), hand-held ultrasound pachymeter (DGH-500) and a specular microscope (SP-3000P).MethodsCentral corneal thickness (CCT) was analyzed in this prospective randomized study that included 32 patients (18 men and 14 women) aged 21–24 years. Measurements were obtained in two sessions, one week apart, by two examiners with three devices in a randomized order. Nine measurements were taken (three with each device) on one randomly selected eye of each patient in each measurement session. The coefficient of repeatability and interobserver reproducibility for the values of each method were calculated. The limits of agreement between techniques were also evaluated.ResultsThere were no significant differences in CCT values between sessions for each of the three devices (P > 0.05). The repeatability coefficients for the Artemis-2 (±8 μm/±9 μm) were superior to those of the SP-3000P (±9 μm/±11 μm) and DGH 500 (±12 μm/±12 μm) in session 1/session 2 respectively, while the interobserver reproducibility index (differences between session 1 and session 2) was superior for the SP-3000P (±17 μm) with respect to DHG-500 (±29 μm) and the Artemis-2 (±31 μm). In session 1 and session 2, the limits of agreement between the techniques were 35 μm to −31 μm and 34 to −20 μm, respectively, for DGH-500 versus Artemis-2, 73 μm to 3 μm and 60 μm to 9 μm for Artemis-2 versus SP-3000P, and 58 μm to 22 μm and 72 μm to 10 μm for DGH-500 versus SP-3000P comparisons. The DGH-500 and Artemis-2 gave similar values (P > 0.05) in both sessions, but both (Artemis-2 and DGH-500) values were significantly greater than that of the SP-3000P (P < 0.05) in both sessions.ConclusionRepeatability was comparably good for the three techniques. However, interobserver reproducibility was approximately twice as good with the SP-3000P compared with the other two devices. The Artemis-2 CCT values consistently agreed with the DGH-500 and less so with the SP-3000P. The Artemis-2 provided CCT values that were, on average, 38 μm and 34 μm greater than that of the SP-3000P in session 1 and session 2, respectively.

Evaluation of the Endothelial Cell Density and the Central Corneal Thickness in Pseudoexfoliation Syndrome and Pseudoexfoliation Glaucoma

“…Modern specular microscopes use advanced computer software to analyze the size, shape, and density of the endothelial cells and allow for the measuring of the central corneal thickness (pachymetry). In many comparison studies specular microscopy, especially model Topcon SP-3000P, has been defined to be more accurate and more reliable than the more common ultrasound pachymetry (USP) [ 13 – 15 ].…”

Characterization of Native Honey Bee Subspecies in Republic of Benin Using Morphometric and Genetic Tools

“…In addition, two parameters were calculated; the total leg length per bee (TLL) equalled the sum of FL,TL and BL and the cubital index per bee was defined as CI = b/a. The repeatability of the measuring methods was obtained by using the same measuring tools (Microscopes, photo adapter, slides and adhesive cover) and the same operator who performed the operation during the same period of the day (British Standards Institution (1975); (Bland & Altman, 1986;Ogbuehi & Osuagwu, 2012). The repeatability was first tested and accepted (r%<0.01) by performing twice the different measurements on two groups of ten bees from one colony.…”

Cornea and anterior eye assessment with slit lamp biomicroscopy, specular microscopy, confocal microscopy, and ultrasound biomicroscopy

“…High-frequency digital UBM or very high-frequency digital UBM (Artemis [ArcScan Inc, Morrison, Colorado]) is a recent technology that allows in vivo corneal epithelium measurement,[ 46 47 48 ] stromal measurement,[ 49 ] flap and residual stromal bed measurement in LASIK procedures,[ 50 ] and in anterior or posterior lamellar keratoplasty,[ 51 52 53 54 ] for the whole cornea; providing valuable information in keratoconus screening. [ 55 56 57 ] Anterior and posterior chamber dimensions[ 58 ] or the assessment of different glaucomatous diseases (including pupillary block or plateau iris syndrome) are, also, possible with this technology.…”