ABSTRACT

Purpose

To determine the limits of normal interocular symmetry and the repeatability of central corneal thickness (CCT) and endothelial cell morphology and density.

Methods

Two hundred and seventy-eight subjects (age: 10.9–80.7 years) with healthy eyes were studied. CCT as well as endothelial cell morphology and density were measured by non-contact specular microscopy. Three measurements were obtained per eye per participant. Upper and lower tolerance limits of normal interocular symmetry were defined as the 2.5th and 97.5th percentiles of the interocular differences in CCT, endothelial cell density (CECD), coefficient of variation (CoV), hexagonality, and cell size. Repeatability was determined using the intraclass coefficient correlation (ICC), the coefficient of variation (CV), and the test–retest variability standard deviation (TRTSD).

Results

The mean interocular differences were −1.05 ± 17.5 µm (p = .32) for CCT and 0.5 ± 90.8 cells/mm² (p = .76) for CECD. The 2.5th and 97.5th percentiles of the interocular differences were −13.9 and 15.4 µm for CCT and −177.4 cells/mm² to 182.0 cells/mm² for CECD. Only interocular difference in CoV correlated weakly with age (r = −0.22, P < .001). ICCs were 0.93 (95% CI: 0.89–0.96, P < .001) for CCT and 0.95 (0.94–0.96, P < .001) for CECD. CV and TRTSD were 1.2% ± 5.3% and 4.4 ± 3.4 µm for CCT and 2.4% ± 3.9% and 17.7 ± 7.7 cells/mm² for CECD, respectively.

Conclusions

CCT and CECD showed good repeatability and interocular symmetry in normal Congolese subjects. Absolute interocular differences in CCT and CECD exceeding 15.5 µm and 182 cells/mm², respectively, should be considered suspicious and investigated. When comparing two intrasession measurements from the same eye, a difference of approximately 4.5 µm in CCT and 18 cells/mm² or greater may be considered statistically significant.

中文翻译：

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刚果人健康眼睛中央角膜厚度和角膜内皮细胞形态和密度的眼间对称性和可重复性

摘要

目的

确定正常眼间对称性的限制以及中央角膜厚度（CCT）和内皮细胞形态和密度的可重复性。

方法

研究了 278 名眼睛健康的受试者（年龄：10.9-80.7 岁）。通过非接触镜面显微镜测量 CCT 以及内皮细胞形态和密度。每个参与者每只眼睛获得三个测量值。正常眼间对称性的上限和下限被定义为 CCT、内皮细胞密度 (CECD)、变异系数 (CoV)、六边形和细胞大小的眼间差异的第 2.5 和第 97.5 个百分位数。使用组内系数相关性 (ICC)、变异系数 (CV) 和重测变异性标准差 (TRTSD) 确定重复性。

结果

CCT的平均眼间差异为 -1.05 ± 17.5 µm ( p = .32)，CECD 为 0.5 ± 90.8 个细胞/mm ² ( p = .76)。CCT 眼间差异的第 2.5 和第 97.5 百分位数分别为 -13.9 和 15.4 µm，CECD 为 -177.4 个细胞/mm ²至 182.0 个细胞/mm ²。只有 CoV 的眼间差异与年龄相关性较弱（r = -0.22，P < .001）。CCT 的ICC 为 0.93（95% CI：0.89–0.96，P < .001），CECD 的 ICC 为 0.95（0.94–0.96，P < .001）。CCT 的 CV 和 TRTSD 分别为 1.2% ± 5.3% 和 4.4 ± 3.4 µm，CECD 的 CV 和 TRTSD 分别为 2.4% ± 3.9% 和 17.7 ± 7.7 个细胞/mm ²。

结论

CCT 和 CECD 在正常刚果受试者中表现出良好的可重复性和眼间对称性。CCT 和 CECD 的绝对眼间差异分别超过 15.5 µm 和 182 个细胞/mm ²，应被视为可疑和调查。^{当比较来自同一只眼睛的两个会话内测量值时，CCT 和 18 个细胞/mm 2}或更大的差异约为 4.5 µm可能被认为具有统计学意义。