Kish Kathleen E, Yuan Alex, Weiland James D
University of Michigan.
Cole Eye Institute, Cleveland Clinic Foundation.
Res Sq. 2023 Aug 2:rs.3.rs-3168193. doi: 10.21203/rs.3.rs-3168193/v1.
Retinal prostheses stimulate inner retinal neurons to create visual perception for blind patients. Implanted arrays have many small electrodes, which act as pixels. Not all electrodes induce perception at the same stimulus amplitude, requiring clinicians to manually establish a visual perception threshold for each one. Phosphenes created by single-electrode stimuli can also vary in shape, size, and brightness. Computational models provide a tool to predict inter-electrode variability and automate device programming. In this study, we created statistical and patient-specific field-cable models to investigate inter-electrode variability across seven epiretinal prosthesis users. Our statistical analysis revealed that retinal thickness beneath the electrode correlated with perceptual threshold, with a significant fixed effect across participants. Electrode-retina distance and electrode impedance also correlated with perceptual threshold for some participants, but these effects varied by individual. We developed a novel method to construct patient-specific field-cable models from optical coherence tomography images. Predictions with these models significantly correlated with perceptual threshold for 80% of participants. Additionally, we demonstrated that patient-specific field-cable models could predict retinal activity and phosphene size. These computational models could be beneficial for determining optimal stimulation settings , circumventing the trial-and-error testing of a large parameter space in clinic.
视网膜假体刺激视网膜内层神经元，为盲人患者创造视觉感知。植入阵列有许多小电极，这些电极充当像素。并非所有电极在相同刺激幅度下都会诱发感知，这就要求临床医生为每个电极手动建立视觉感知阈值。单电极刺激产生的光幻视在形状、大小和亮度上也会有所不同。计算模型提供了一种工具，可预测电极间的变异性并自动进行设备编程。在本研究中，我们创建了统计模型和针对患者的场线模型，以研究七名视网膜外假体使用者的电极间变异性。我们的统计分析表明，电极下方的视网膜厚度与感知阈值相关，在所有参与者中存在显著的固定效应。电极与视网膜的距离以及电极阻抗在一些参与者中也与感知阈值相关，但这些效应因个体而异。我们开发了一种从光学相干断层扫描图像构建针对患者的场线模型的新方法。这些模型的预测与80%的参与者的感知阈值显著相关。此外，我们证明了针对患者的场线模型可以预测视网膜活动和光幻视大小。这些计算模型可能有助于确定最佳刺激设置，避免在临床中对大参数空间进行反复试验测试。
