Wang Wei, Qiao Qingli, Gao Weiping, Wu Jun
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2014 Dec;31(6):1255-9, 1271.
We studied the influence of electrode array parameters on temperature distribution to the retina during the use of retinal prosthesis in order to avoid thermal damage to retina caused by long-term electrical stimulation. Based on real epiretinal prosthesis, a three-dimensional model of electrical stimulation for retina with 4 X 4 microelectrode array had been established using the finite element software (COMSOL Multiphysics). The steady-state temperature field of electrical stimulation of the retina was calculated, and the effects of the electrode parameters such as the distance between the electrode contacts, the materials and area of the electrode contact on temperature field were considered. The maximum increase in the retina steady temperature was about 0. 004 degrees C with practical stimulation current. When the distance between the electrode contacts was changed from 130 microm to 520 microm, the temperature was reduced by about 0.006 microC. When the contact radius was doubled from 130 microm to 260 microm, the temperature decrease was about 0.005 degrees C. It was shown that there were little temperature changes in the retina with a 4 x 4 epiretinal microelectrode array, reflecting the safety of electrical stimulation. It was also shown that the maximum temperature in the retina decreased with increasing the distance between the electrode contacts, as well as increasing the area of electrode contact. However, the change of the maximum temperature was very small when the distance became larger than the diameter of electrode contact. There was no significant difference in the effects of temperature increase among the different electrode materials. Rational selection of the distance between the electrode contacts and their area in electrode design can reduce the temperature rise induced by electrical stimulation.
我们研究了视网膜假体使用过程中电极阵列参数对视网膜温度分布的影响，以避免长期电刺激对视网膜造成热损伤。基于实际的视网膜外假体，使用有限元软件（COMSOL Multiphysics）建立了具有4×4微电极阵列的视网膜电刺激三维模型。计算了视网膜电刺激的稳态温度场，并考虑了电极参数如电极触点间距、电极触点材料和面积对温度场的影响。在实际刺激电流下，视网膜稳态温度的最大升高约为0.004摄氏度。当电极触点间距从130微米变为520微米时，温度降低约0.006微摄氏度。当接触半径从130微米加倍至260微米时，温度降低约0.005摄氏度。结果表明，4×4视网膜外微电极阵列对视网膜温度变化影响很小，反映了电刺激的安全性。还表明，视网膜中的最高温度随着电极触点间距的增加以及电极接触面积的增加而降低。然而，当距离大于电极触点直径时，最高温度的变化非常小。不同电极材料之间温度升高的影响没有显著差异。在电极设计中合理选择电极触点间距及其面积可以降低电刺激引起的温度升高。
