Background:In low vision patients, the assessment of contrast sensitivity is an essential tool to determine the stage of visual impairment. However, traditional contrast sensitivity tests rely on verbal feedback, and the expertise of the examiner. Objective:In the current study, a fast, OKN-based virtual diagnosis tool was developed estimating contrast sensitivity automatically without active cooperation of the patient as well as the practitioner within 3.5 minutes. Methods:In a HTC Vive headset with an SMI-eye tracker, a virtual rotating drum was implemented, and an algorithm was developed, evaluating the occurrence of an OKN. The tool was evaluated in healthy subjects as well as under low vision simulation for two spatial frequencies and four contrasts. It was then compared to two contrast sensitivity estimates based on manual report on the orientation of static gratings as well as the movement direction of translating gratings. Results:An algorithm was developed, which matched ground truth ratings of occurrence of OKN with an accuracy of 88 %. Furthermore, known differences in contrast sensitivity between healthy and low vision conditions as well as a decrease in contrast sensitivity for lower spatial frequencies was successfully reproduced in the developed tool. Conclusions:The developed OKN-based sensitivity test represents a reliable proof of concept for technology readiness of virtual reality-based screening tools of visual function in practice, specifically in patients with difficulties to report perception verbally, or under conditions, where no experienced examiner is present.

中文翻译：

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VR 中基于独立无合作 OKN 的低视力对比敏感度估计 - 一项试点研究。

背景：在低视力患者中，对比敏感度的评估是确定视力障碍阶段的重要工具。然而，传统的对比敏感度测试依赖于口头反馈和检查者的专业知识。目标：在当前的研究中，开发了一种基于 OKN 的快速虚拟诊断工具，可在 3.5 分钟内自动估计对比敏感度，而无需患者和医生的积极配合。方法：在带有 SMI 眼动仪的 HTC Vive 耳机中，实现了虚拟转鼓，并开发了一种算法，评估 OKN 的发生。该工具在健康受试者以及低视力模拟下针对两个空间频率和四个对比进行了评估。然后将其与基于静态光栅方向以及平移光栅移动方向的手动报告的两个对比敏感度估计值进行比较。结果：开发了一种算法，该算法以 88% 的准确率匹配 OKN 发生的真实评级。此外，在开发的工具中成功再现了健康和低视力条件之间对比敏感度的已知差异以及较低空间频率对比敏感度的降低。结论：开发的基于 OKN 的敏感性测试代表了基于虚拟现实的视觉功能筛查工具在实践中的技术准备的可靠概念证明，特别是在难以口头报告感知的患者中，或在没有经验丰富的检查员的情况下当下。