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首页> 外文期刊>Optometry and vision science: official publication of the American Academy of Optometry >Contributions of optical and non-optical blur to variation in visual acuity.
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Contributions of optical and non-optical blur to variation in visual acuity.

机译：光学和非光学模糊对视敏度变化的贡献。

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PURPOSE: To determine the relative contributions of optical and non-optical sources of intrinsic blur to variations in visual acuity (VA) among normally sighted subjects. METHODS: Best-corrected VA of 16 normally sighted subjects was measured using briefly presented (59 ms) tumbling E optotypes that were either unblurred or blurred through convolution with Gaussian functions of different widths. A standard model of intrinsic blur was used to estimate each subject's equivalent intrinsic blur (sigmaint) and VA for the unblurred tumbling E (MAR0). For 14 subjects, a radially averaged optical point spread function due to higher-order aberrations was derived by Shack-Hartmann aberrometry and fit with a Gaussian function. The standard deviation of the best-fit Gaussian function defined optical blur (sigmaopt). An index of non-optical blur (eta) was defined as 1 - sigmaopt/sigmaint. A control experiment was conducted on five subjects to evaluate the effect of stimulus duration on MAR0 and sigmaint. RESULTS.: The logarithm of the minimum angle of resolution (logMAR) for the briefly presented E was correlated significantly with log sigmaint (r = 0.95, p < 0.01), consistent with previous work. However, logMAR was not correlated significantly with log sigmaopt (r = 0.46, p = 0.11). For subjects with logMAR equivalent to ~20/20 or better, logMAR was independent of log eta, whereas for subjects with larger logMAR values, logMAR was proportional to log eta. The control experiment showed a statistically significant effect of stimulus duration on logMAR (p < 0.01) but a non-significant effect on sigmaint (p = 0.13). CONCLUSIONS: The relative contributions of optical and non-optical blur to VA varied among the subjects and were related to the subject's VA. Evaluating optical and non-optical blur may be useful for predicting changes in VA following procedures that improve the optics of the eye in patients with both optical and non-optical sources of VA loss.
机译：目的：确定内在模糊的光学和非光学光源对正常视力对象视力（VA）变化的相对贡献。方法：采用短暂呈现（59毫秒）的翻滚E视力测量最佳矫正的VA，该视力通过不同宽度的高斯函数卷积而变得不模糊或模糊。使用内在模糊的标准模型来估计每个对象的等效内在模糊（sigmaint）和未模糊翻转E（MAR0）的VA。对于14位受试者，通过Shack-Hartmann像差法得出了由于高阶像差引起的径向平均光学点扩展函数，并与高斯函数拟合。最佳拟合高斯函数的标准偏差定义了光学模糊（sigmaopt）。非光学模糊指数（eta）定义为1-sigmaopt / sigmaint。在五个对象上进行了对照实验，以评估刺激持续时间对MAR0和sigmaint的影响。结果：简要介绍的E的最小分辨角（logMAR）的对数与log sigmaint显着相关（r = 0.95，p <0.01），与先前的工作一致。但是，logMAR与log sigmaopt没有显着相关（r = 0.46，p = 0.11）。对于logMAR等于〜20/20或更高的受试者，logMAR与log eta独立，而对于具有较大logMAR值的受试者，logMAR与log eta成正比。对照实验显示，刺激持续时间对logMAR具有统计学意义（p <0.01），对sigmaint的影响无统计学意义（p = 0.13）。结论：光学模糊和非光学模糊对VA的相对贡献因受试者而异，并且与受试者的VA有关。评估光学和非光学模糊对于遵循VA损失的光学和非光学来源的患者改善眼睛视力的程序，可能有助于预测VA的变化。

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