Finn Kathleen E, Zander Hans J, Graham Robert D, Lempka Scott F, Weiland James D
Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA and are associated with the Biointerfaces Institute.
IEEE Open J Eng Med Biol. 2020;1:190-196. doi: 10.1109/ojemb.2020.3001563. Epub 2020 Jun 11.
Retinal prosthesis performance is limited by the variability of elicited phosphenes. The stimulating electrode's position with respect to retinal ganglion cells (RGCs) affects both perceptual threshold and phosphene shape. We created a modeling framework incorporating patient-specific anatomy and electrode location to investigate RGC activation and predict inter-electrode differences for one Argus II user.
We used ocular imaging to build a three-dimensional finite element model characterizing retinal morphology and implant placement. To predict the neural response to stimulation, we coupled electric fields with multi-compartment cable models of RGCs. We evaluated our model predictions by comparing them to patient-reported perceptual threshold measurements.
Our model was validated by the ability to replicate clinical impedance and threshold values, along with known neurophysiological trends. Inter-electrode threshold differences correlated with results.
We developed a patient-specific retinal stimulation framework to quantitatively predict RGC activation and better explain phosphene variations.
视网膜假体的性能受到诱发光幻视变异性的限制。刺激电极相对于视网膜神经节细胞（RGC）的位置会影响感知阈值和光幻视形状。我们创建了一个结合患者特定解剖结构和电极位置的建模框架，以研究RGC激活并预测一名阿格斯II型用户的电极间差异。
我们使用眼部成像构建了一个表征视网膜形态和植入物位置的三维有限元模型。为了预测对刺激的神经反应，我们将电场与RGC的多室电缆模型相结合。我们通过将模型预测结果与患者报告的感知阈值测量结果进行比较来评估模型预测。
我们的模型通过复制临床阻抗和阈值以及已知神经生理趋势的能力得到验证。电极间阈值差异与结果相关。
我们开发了一个患者特定的视网膜刺激框架，以定量预测RGC激活并更好地解释光幻视变化。
