Thompson A M, Li T, Peck L B, Howland H C, Counts R, Bobier W R
Section of Neurobiology and Behavior, Comeli University, Ithaca, New York, USA.
Optom Vis Sci. 1996 Oct;73(10):644-52. doi: 10.1097/00006324-199610000-00003.
The Fortune Optical (Tomey ViVA) VRB-100 video refractor was tested to determine its accuracy and precision in measuring manifest refractions of human eyes with and without cycloplegia. The specific issues addressed included its accuracy in measuring spherical and cylindrical refractive errors and its precision in refracting near emmetropia.
To determine its ability to measure moderate to high (> 4.00 D) myopia, we compared the VIVA's refractions to those taken by a Canon Autorefractor R1 and a retinoscopist. A spherical lens series from -7.00 to + 7.00 D at 1.00 D intervals, or -5.00 to + 5.00 at 0.50 D intervals, was placed over a subject's eye, which was then covered by an infrared (IR) filter, refracted, and analyzed to determine the VIVA's ability to measure spheres. Subjects with refractive errors of -2.00 to + 2.00 DS (diopters sphere) and 0 to 1.00 DC (diopters cylinder) were refracted 7 to 15 times during 1 sitting to determine the VIVA's precision. The instrument's accuracy in measuring cylinders was tested by placing + 3.00 to -3.00 D cylinders (at 0.50 D intervals) over the eyes of subjects at 0 degree, 45 degrees, 60 degrees, 75 degrees, 90 degrees, 105 degrees, 120 degrees, and 135 degrees.
The VIVA measured spheres of +/- 3.00 D with a root mean squared (rms) error of 0.5 +/- 0.1 D. Beyond this power, its accuracy progressively worsened. In some subjects, irregular intensity profiles compromised the VIVA's accuracy even with low spherical refractive errors. The VIVA was very precise in measuring spheres from + 2.00 to -2.00 D and cylinders from 0 to 1.00 D. Although the ViVA adequately measured all cylinder powers at 0 degree and 90 degrees, the accuracy of cylindrical power measurement decreased with obliquity; only cylinders < or = 1.00 D magnitude were accurately measured at 45 degrees and 135 degrees.
We conclude that, although the ViVA offers many attractive features for vision screening, it is seriously limited by its inability to property detect and measure oblique astigmatic errors.
对富士伦光学（托米维瓦）VRB - 100视频验光仪进行测试，以确定其在测量有无睫状肌麻痹情况下人眼的显验光度数时的准确性和精确性。所涉及的具体问题包括其在测量球镜和柱镜屈光不正时的准确性以及在验光接近正视眼时的精确性。
为确定其测量中度至高度（> 4.00 D）近视的能力，我们将维瓦验光仪的验光结果与佳能自动验光仪R1及检影验光师的验光结果进行比较。以1.00 D的间隔设置从 - 7.00至 + 7.00 D的球镜系列，或以0.50 D的间隔设置从 - 5.00至 + 5.00 D的球镜系列，放置在受试者眼睛上，然后用红外（IR）滤光片覆盖眼睛，进行验光并分析，以确定维瓦验光仪测量球镜的能力。对球镜屈光不正为 - 2.00至 + 2.00 DS（球镜屈光度）且柱镜屈光不正为0至1.00 DC（柱镜屈光度）的受试者在一次检查中进行7至15次验光，以确定维瓦验光仪的精确性。通过将 + 3.00至 - 3.00 D的柱镜（以0.50 D的间隔）放置在0度、45度、60度、75度、90度、105度、120度和135度的受试者眼睛上来测试该仪器测量柱镜的准确性。
维瓦验光仪测量 +/- 3.00 D球镜时的均方根（rms）误差为0.5 +/- 0.1 D。超过此度数，其准确性逐渐变差。在一些受试者中，即使球镜屈光不正度数较低，不规则的强度分布也会影响维瓦验光仪的准确性。维瓦验光仪在测量 + 2.00至 - 2.00 D的球镜和0至1.00 D的柱镜时非常精确。尽管维瓦验光仪能够充分测量0度和90度时所有柱镜度数，但柱镜度数测量的准确性随倾斜度增加而降低；在45度和135度时，仅能准确测量<或 = 1.00 D度数的柱镜。
我们得出结论，尽管维瓦验光仪在视力筛查方面具有许多吸引人的特性，但它因无法准确检测和测量斜向散光误差而受到严重限制。
