Visual Performance Using a Retinal Prosthesis in Three Subjects With Retinitis Pigmentosa

Yanai, D.; Weiland, James D.; Mahadevappa, Manjunatha; Greenberg, Robert J.; Fine, Ione; Humayun, Mark S.

doi:10.1016/j.ajo.2007.01.027

Cited by 218 publications

(151 citation statements)

References 18 publications

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“…Damaged photoreceptors can be bypassed by electrically stimulating the surviving inner retinal neurons through a device implanted on the retinal surface. The development of such retinal prosthetics has progressed steadily during the past decade (Zrenner, 2002;Loewenstein et al, 2004;Veraart et al, 2004;Weiland et al, 2005;Javaheri et al, 2006): long-term low-resolution implants in human patients have recently been shown to restore rudimentary perception of light and simple pattern recognition (Yanai et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

High-Resolution Electrical Stimulation of Primate Retina for Epiretinal Implant Design

Sekirnjak¹,

Hottowy²,

Sher³

et al. 2008

J. Neurosci.

188

223

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The development of retinal implants for the blind depends crucially on understanding how neurons in the retina respond to electrical stimulation. This study used multielectrode arrays to stimulate ganglion cells in the peripheral macaque retina, which is very similar to the human retina. Analysis was restricted to parasol cells, which form one of the major high-resolution visual pathways in primates. Individual cells were characterized using visual stimuli, and subsequently targeted for electrical stimulation using electrodes 9 -15 m in diameter.

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Section: Introductionmentioning

confidence: 99%

High-Resolution Electrical Stimulation of Primate Retina for Epiretinal Implant Design

Sekirnjak¹,

Hottowy²,

Sher³

et al. 2008

J. Neurosci.

188

223

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“…A main system of the prototypes is to generate electric currents to stimulate the remaining retinal neurons in the degenerated retina: digital camera-captured images are transferred to electric signals which are outputted as electric currents from a multi-electrode array placed around the neurosensory retina. [1][2][3][4][5] The multi-electrode array would be placed on the surface of the retina in the vitreous, 4 in the subretinal space between the retina and the retinal pigment epithelium, 2 or in the subchoroidal space between the sclera and choroid. 5 Another system for the retinal prosthesis is to use photodiodes.…”

Section: Introductionmentioning

confidence: 99%

Behavior tests and immunohistochemical retinal response analyses in RCS rats with subretinal implantation of Okayama-University-type retinal prosthesis

et al. 2013

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We have developed a photoelectric dye-coupled polyethylene film as a prototype of retinal prosthesis, named "Okayama University-type retinal prosthesis. The purposes of this study are to conduct behavior tests to assess vision in Royal College of Surgeons (RCS) rats which underwent subretinal implantation of the dye-coupled film, and are also to reveal the retinal response to the dye-coupled film by immunohistochemistry.Polyethylene films were made of polyethylene powder at refined purity, and photoelectric dyes were coupled to the film surface at higher density, compared with the prototype. The dye-coupled film or the dye-uncoupled plain film, as a control, was implanted subretinally from a scleral incision in both eyes of a RCS rat at 6 weeks of the age. Behavior tests, 2, 4, 6, and 8 weeks after the implantation, were conducted by observing head-turning or body-turning in the direction, consistent with clockwise or anticlockwise rotation of a black-and-white-striped drum around a transparent cage, housed with a rat. After the behavior tests at 8 weeks, rats' eyes were enucleated to confirm the subretinal implantation of the films and were processed for immunohistochemistry. In the behavior tests, the number of head-turning, consistent with the direction of the drum rotation, was significantly larger in RCS rats with dye-coupled film implantation, compared with rats with plain film implantation (P<0.05, 3 repeated-measure ANOVA). The number of apoptotic neurons was significantly smaller in the eyes with the dye-coupled film implantation, compared to the eyes with the plain film (P<0.05, Mann-Whitney U-test). In conclusion, subretinal implantation of the photoelectric dye-coupled films restored the vision in RCS rats and prevented the remaining retinal neurons from apoptosis.

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“…Klinik denemelerde elde edilen fosfen algısı yuvarlak, oval olarak tanımlandığı gibi düzensiz şekillerde de raporlanmıştır [25,26]. Düzenli fosfen oluşumu için lokalize uyartım ile yalnızca uyartım yapılan elektrot etrafında alan oluşturmak gerekir [27].…”

Section: Sonuçlar Ve Tartişmalar (Results and Discussion)unclassified

Elektrot Etkileşimi ve Uyartım Eşiğinin Azaltılmasına Yönelik Sonlu Elemanlar Yöntemi Tabanlı Yeni Bir Retina Uyartım Stratejisi

Celik

Karagöz

2017

Gazi Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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Dejeneratif göz hastalıkları retinanın dış katmanına zarar vererek fonksiyonelliğini yitirmesine ve görsel algı kaybına neden olmaktadır. Görsel protezler, işlevselliğini kaybetmiş bölgelerin bypass edilerek zarar görmemiş bölgelerin yerleştirilen elektrot dizisi vasıtasıyla elektriksel olarak uyartılarak görsel algının yeniden kazanılmasını sağlayan cihazlardır. Görsel protezler hedeflenen yüksek uzaysal çözünürlükten oldukça uzaktır. Temel problem elektrot etkileşimi nedeniyle elektrot sayısının artırılamamasıdır. Bu çalışmada, elde edilen görsel algının çözünürlüğünü artırılması, uyartım için gerekli güç tüketiminin ve uyartım sonucu dokuda oluşan sıcaklığın azaltılması amacıyla Sonlu Elemanlar Yöntemi kullanılarak geliştirilen retinanın elektriksel uyartımında Merkez-Ağırlıklı Zaman Kaymalı Uyartım Stratejisi önerilmiştir. Bu strateji, yarı-koni biçimli elektrot tasarımı ve konfigürasyonu ile zamanda kaydırılmış ve konuma göre ağırlıklandırılmış elektriksel uyartım yaklaşımını kullanmaktadır. Önerilen stratejinin üstünlüğü konvansiyonel elektrot dizilimi ve uyartım yöntemiyle karşılaştırılmış, daha lokalize uyartım sağlanarak ayırt edilebilir elektrik alan ve akım yoğunluğu dağılımları elde edilmiştir. Konvansiyonel yöntemle uyartım akım eşiği 10 µA seviyesinde iken önerilen stratejide bu değer 0,5-2 µA aralığında elde edilmiştir. Ayrıca, konvansiyonel yöntemle uyartım için harcanan güç 4,19 mW/mm3 ve dokudaki sıcaklık artışı 1,38°C iken sunulan yöntemle bu değerler sırayla 0,239 mW/mm3, 0,4°C olarak bulunmuştur. Önerilen stratejinin yüksek çözünürlüklü retina implant sisteminin geliştirilmesine, çözünürlük, güç tüketimi ve dokudaki sıcaklık artışının sınırlanması çalışmalarına katkı sağlayacağı sonucuna varılmıştır. Degenerative eye diseases damage outer layer of the retina and cause to lost the vision. Visual prostheses are the systems which enable to elicit visual perception through electrical stimulation of the regions that remain intact using electrode arrays at these regions bypassing damaged parts. Spatial resolution of the visual prostheses is far away from the desired value. The main problem is that the number of electrodes couldn't be increased because of electrode interaction. In this study, Central-Weighted Time Shifted Stimulation Strategy which is developed using Finite Element Method is presented which aims both to increase spatial resolution and to decrease power dissipation needed for stimulation and temperature rise on the tissue. This strategy uses semi-cone shaped electrode design and configuration, stimulation approach which is time shifted, weighted depending on the position. Results are compared to the results with conventional electrode layout and stimulation. It is seen that proposed strategy provides discriminable electric field and current density distributions. While stimulation current threshold is 10 µA for conventional method, it ranges 0.5-2 µA for proposed strategy. Furthermore, power dissipation and temperature rise on the tissue are 4.19 mW/mm3 and 1.38°C respectively for c...

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Visual Performance Using a Retinal Prosthesis in Three Subjects With Retinitis Pigmentosa

Cited by 218 publications

References 18 publications

High-Resolution Electrical Stimulation of Primate Retina for Epiretinal Implant Design

High-Resolution Electrical Stimulation of Primate Retina for Epiretinal Implant Design

Behavior tests and immunohistochemical retinal response analyses in RCS rats with subretinal implantation of Okayama-University-type retinal prosthesis

Elektrot Etkileşimi ve Uyartım Eşiğinin Azaltılmasına Yönelik Sonlu Elemanlar Yöntemi Tabanlı Yeni Bir Retina Uyartım Stratejisi

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