Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA.
Vision Res. 2021 Jul;184:23-29. doi: 10.1016/j.visres.2021.02.009. Epub 2021 Mar 26.
To date, retinal implants are the only available treatment for blind individuals with retinal degenerations such as retinitis pigmentosa. Argus II is the only visual implant with FDA approval, with more than 300 users worldwide. Argus II stimulation is based on a grayscale image coming from a head-mounted visible-light camera. Normally, the 11×19 field of view of the Argus II user is full of objects that may elicit similar phosphenes. The prosthesis cannot meaningfully convey so much visual information, and the percept is reduced to an ambiguous impression of light. This study is aimed at investigating the efficacy of simplifying the video input in real-time using a heat-sensitive camera. Data were acquired from four Argus II users in 5 stationary tasks with either hot objects or human targets as stimuli. All tasks were of m-alternative forced choice design where precisely one of the m≥2 response alternatives was defined to be "correct" by the experimenter. To compare performance with heat-sensitive and normal cameras across all tasks, regardless of m, we used an extension of signal detection theory to latent variables, estimating person ability and item difficulty in d' units. Results demonstrate that subject performance was significantly better across all tasks with the thermal camera compared to the regular Argus II camera. The future addition of thermal imaging to devices with very poor spatial resolution may have significant real-life benefits for orientation, personal safety, and social interactions, thereby improving quality of life.
迄今为止，视网膜植入物是唯一可用于治疗视网膜变性（如色素性视网膜炎）导致失明的方法。Argus II 是唯一获得 FDA 批准的视觉植入物，全球有 300 多名使用者。Argus II 的刺激基于来自头戴式可见光摄像机的灰度图像。通常，Argus II 用户的 11×19 视野充满了可能产生类似光幻视的物体。该假体无法有效地传达如此多的视觉信息，感知结果简化为对光的模糊印象。本研究旨在调查使用热敏相机实时简化视频输入的效果。从四名 Argus II 用户在 5 个固定任务中获取数据，刺激物为热物体或人体目标。所有任务均采用 m 个替代的强制选择设计，其中 m≥2 个响应选项中的一个由实验者精确定义为“正确”。为了比较所有任务中热敏相机和普通相机的性能，无论 m 如何，我们使用信号检测理论的扩展到潜在变量，以 d' 单位估计人的能力和项目难度。结果表明，与常规 Argus II 相机相比，在所有任务中，热敏相机的受试者表现明显更好。未来在空间分辨率非常低的设备中添加热成像可能会对定向、个人安全和社交互动产生重大的现实生活效益，从而提高生活质量。
