Ogbuehi Kelechi C, Osuagwu Uchechukwu L
Outpatient Clinic, Department of Optometry, King Saud University, Riyadh, Kingdom of Saudi Arabia.
Clin Ophthalmol. 2012;6:761-9. doi: 10.2147/OPTH.S31690. Epub 2012 May 21.
The 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).
Central 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.
There 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.
Repeatability 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.
本研究旨在评估高频超声（Artemis - 2）、手持式超声角膜厚度仪（DGH - 500）和镜面显微镜（SP - 3000P）测量角膜厚度值的可重复性及一致性界限。
在这项前瞻性随机研究中，对32例年龄在21 - 24岁的患者（18名男性和14名女性）的中央角膜厚度（CCT）进行分析。在两个时间段进行测量，间隔一周，由两名检查者使用三种仪器以随机顺序进行。在每个测量时间段，对每位患者一只随机选择的眼睛进行九次测量（每种仪器测量三次）。计算每种方法测量值的重复性系数和观察者间的再现性。同时评估不同技术之间的一致性界限。
三种仪器在不同时间段的CCT值之间均无显著差异（P > 0.05）。在第一个时间段/第二个时间段，Artemis - 2的重复性系数（±8μm/±9μm）分别优于SP - 3000P（±9μm/±11μm）和DGH 500（±12μm/±12μm），而观察者间再现性指数（第一个时间段和第二个时间段之间的差异）方面，SP - 3000P（±17μm）优于DHG - 500（±29μm）和Artemis - 2（±31μm）。在第一个时间段和第二个时间段，DGH - 500与Artemis - 2之间技术的一致性界限分别为35μm至 - 31μm和34μm至 - 20μm，Artemis - 2与SP - 3000P之间为73μm至3μm和60μm至9μm，DGH - 500与SP - 3000P之间为58μm至22μm和72μm至10μm。在两个时间段中，DGH - 500和Artemis - 2给出的数值相似（P > 0.05），但两者（Artemis - 2和DGH - 500）的数值在两个时间段均显著高于SP - 3000P（P < 0.05）。
这三种技术的可重复性都相当好。然而，与其他两种设备相比，SP - 3000P的观察者间再现性约为其他两种设备的两倍。Artemis - 2的CCT值与DGH - 500始终一致，与SP - 3000P的一致性则较差。在第一个时间段和第二个时间段，Artemis - 2提供的CCT值分别比SP - 3000P平均高38μm和34μm。
