Akar Yusuf, Bozkurt Banu, Irkeç Murat, Orhan Mehmet, Karaăgaoglu Ergun
Department of Ophthalmology, Akdeniz University School of Medicine, Antalya, Turkey.
Clin Exp Ophthalmol. 2004 Apr;32(2):142-6. doi: 10.1111/j.1442-9071.2004.00799.x.
To determine the effect of scan repetition during a single visit for improved reproducibility of optic nerve head topographic measurements.
One randomly selected eye of 20 healthy subjects with no systemic or ocular disease was evaluated. Half of the subjects were under 30 years of age and the other half were older than 60 years. Five independent image series, each consisting of 10 newly recorded consecutive images, were obtained for each subject over a period of 10 weeks with a confocal scanning laser ophthalmoscope, the Top SS. Subjects were divided into two groups according to disc area being either smaller or larger than 2 mm2. Reproducibility of the measurements in three parameters (volume below, half depth area and the average depth) were calculated for each set of scans. The coefficient of variation (standard deviation divided by the mean) was taken as the measure of reproducibility. Repeated measures of analysis of variation and independent sample t-test were used for statistical analysis. Statistical significance was set as P < 0.05.
Both age groups were found to be equally distributed with respect to sex. There were no significant intergroup differences in keratometry, pupil diameter or refractive error. Increasing the scan repetition per visit up to five improved the reproducibility of the measurements. Further increases in scans per visit reduced the reproducibility. Subjects with larger discs and older age were found to have lower coefficients of variation for topographic measurements.
Normal subjects should be examined at least three to four times per visit to have significantly improved reliability of measurements of optic nerve head topography. Factors associated with decreased reproducibility included older age, smaller discs, and more than five scans per visit. Sex, refraction and pupil diameter were shown to have no effect on the reproducibility.
确定单次就诊期间扫描重复次数对提高视神经乳头地形图测量可重复性的影响。
对20名无全身或眼部疾病的健康受试者的一只随机选择的眼睛进行评估。一半受试者年龄在30岁以下，另一半年龄在60岁以上。使用共焦扫描激光眼科显微镜Top SS，在10周内为每个受试者获取5个独立的图像序列，每个序列由10张新记录的连续图像组成。根据视盘面积小于或大于2 mm²将受试者分为两组。计算每组扫描中三个参数（下方体积、半深度面积和平均深度）测量的可重复性。变异系数（标准差除以均值）作为可重复性的度量。采用重复测量方差分析和独立样本t检验进行统计分析。统计学显著性设定为P < 0.05。
两个年龄组在性别分布上均等。角膜曲率、瞳孔直径或屈光不正方面两组间无显著差异。将每次就诊的扫描重复次数增加至5次可提高测量的可重复性。每次就诊扫描次数的进一步增加会降低可重复性。发现视盘较大和年龄较大的受试者地形图测量的变异系数较低。
正常受试者每次就诊应至少检查三到四次，以显著提高视神经乳头地形图测量的可靠性。与可重复性降低相关的因素包括年龄较大、视盘较小以及每次就诊扫描超过5次。性别、屈光和瞳孔直径对可重复性无影响。
