Rubin A, Harris W F
Department of Optometry, Rand Afrikaans University, South Africa.
Optom Vis Sci. 2001 Oct;78(10):744-53. doi: 10.1097/00006324-200110000-00014.
This paper demonstrates a multivariate approach to understanding the complicated relations of visual acuity to refractive state or ametropia. Other approaches, as previously used, included graphical representations of lines or profiles of iso-oxyopia (Peters, 1961). But one limitation of Peters' method is that cylinder axis was ignored. However, here the relationship between visual acuity and refractive power will be represented by estimated closed surfaces of constant visual acuity in symmetric dioptric power space. At or near the common center (of several closed surfaces, for example) is the refractive compensation. Coming outwards from such a center, the visual acuity drops in all directions in the space. The primary purpose of this paper was to present estimated closed surfaces of constant visual acuity for several eyes. Various procedures were performed on several subjects including measurement of iris aperture diameter, subjective refraction, and autorefraction. Thereafter, an automated phoropter and either Jackson cross-cylinders or spheres were used to influence dioptric blur or defocus in the subjects. The visual stimulus was a computer-generated nondirectional or meridionally independent letter O. Ovoidal surfaces fit the measurements obtained (with Jackson cross-cylinders and spheres) better than ellipsoidal surfaces. The cross-section, in symmetric dioptric power space, at powers with the same nearest equivalent sphere as the refractive compensation is elliptical in many cases and reflects a dependence of visual acuity on cylinder axis. The surfaces differ when powers are changed so that one is moving away from (decompensation surfaces) or toward (accompensation surfaces) the refractive compensation. The multivariate and graphical methods used in this paper probably have implications for the direction of future research in a number of areas involving measures of vision function such as autorefraction, retinoscopy, subjective refraction, and visual acuity.
本文展示了一种多变量方法，用于理解视力与屈光状态或屈光不正之间的复杂关系。以前使用的其他方法包括等视力线或轮廓的图形表示（彼得斯，1961年）。但彼得斯方法的一个局限性是忽略了柱镜轴。然而，在这里，视力与屈光力之间的关系将由对称屈光力空间中恒定视力的估计封闭曲面来表示。在（例如几个封闭曲面的）共同中心处或其附近是屈光补偿。从这样一个中心向外，空间中各个方向的视力都会下降。本文的主要目的是呈现几只眼睛的恒定视力估计封闭曲面。对几名受试者进行了各种程序，包括测量虹膜孔径直径、主观验光和自动验光。此后，使用自动验光仪和杰克逊交叉柱镜或球镜来影响受试者的屈光性模糊或散焦。视觉刺激是计算机生成的无方向性或子午线独立的字母O。卵形曲面比椭圆形曲面更符合（使用杰克逊交叉柱镜和球镜）获得的测量结果。在对称屈光力空间中，与屈光补偿具有相同最近等效球镜度的屈光力处的横截面在许多情况下是椭圆形的，反映了视力对柱镜轴的依赖性。当屈光力改变时，这些曲面会有所不同，即当一个人远离（去补偿曲面）或朝向（再补偿曲面）屈光补偿时。本文中使用的多变量和图形方法可能对未来一些涉及视力功能测量的领域的研究方向有影响，如自动验光、视网膜检影、主观验光和视力。
