Foundation for Glaucoma Research, San Francisco; University of California at Davis, Davis; and Ophthalmic Imaging Systems, Sacramento, California, U.S.A.
J Glaucoma. 1994 Spring;3(1):17-27.
The Glaucoma-Scope is designed to measure the topography of the optic nerve head. Depth measurements are reported as a grid of cells where each value represents the average depth of an area 55 +/- 100 mum in size. The Glaucoma-Scope was tested on 10 normal and 18 glaucomatous subjects, >40 years of age. Two separate visits were simulated for each patient. To estimate measurement variability, depth values were analyzed in groups of 25 cells, comprising "areas of interest." A components of variance analysis was used to compare the variability of the difference between the depth of an area measured at the first and second visits. The analysis yields within visit standard deviation of the difference between depth measurements taken within the same visit (Sw), the standard deviation of the difference between depth measurements taken at separate visits (Sb), and the total standard deviation of the difference between depth measurements (Sd). For flat areas outside the optic nerve head, Sd = 11.68 mum. For flat areas within the optic nerve head, Sd = 17.91 mum. For areas at the bottom of the cup, which includes sloped areas, Sd = 32.01 mum. For sloped areas within the optic nerve head, Sd = 20.78 mum. For areas over a vessel, Sd = 34.76 mum. The mean standard deviation of a single pixel in the Glaucoma-Scope measurement is 15.42 mum. The Glaucoma-Scope measurements are highly reproducible for both healthy and glaucomatous subjects. Local variability in depth measurements should be considered when evaluating change in optic nerve head topography.
视野计用于测量视神经头的地形。深度测量以单元格网格报告，每个值代表大小为 55 +/- 100 微米的区域的平均深度。视野计在 10 名正常人和 18 名年龄大于 40 岁的青光眼患者中进行了测试。为每位患者模拟了两次单独的就诊。为了估计测量的可变性，将深度值按 25 个细胞的组进行分析，这些细胞组成“感兴趣的区域”。使用方差分量分析来比较在第一次和第二次就诊中测量的同一区域的深度之间的差异的可变性。该分析产生了在同一就诊中进行的深度测量之间的差异的测量内标准偏差（Sw）、在不同就诊中进行的深度测量之间的差异的标准偏差（Sb）以及深度测量之间的总标准偏差（Sd）。对于视神经头外部的平坦区域，Sd = 11.68 微米。对于视神经头内的平坦区域，Sd = 17.91 微米。对于杯底的区域，包括倾斜区域，Sd = 32.01 微米。对于视神经头内的倾斜区域，Sd = 20.78 微米。对于在血管上方的区域，Sd = 34.76 微米。Glaucoma-Scope 测量中的单个像素的平均标准偏差为 15.42 微米。视野计对健康和青光眼患者的测量都具有高度的可重复性。在评估视神经头地形的变化时，应考虑深度测量的局部可变性。
