Retinal Prosthesis Dissertation - Student Home Pages

“For these implantable devices to be most effective, they must be biomimetic; that is,
they must restore a lost function that mimics the biology”, “When treating a medical
problem, focus on the needs of the patient.”
[126]
Intraocular Retinal Prosthesis
“Recent clinical trials have shown that a prototype epiretinal implant, despite having
few electrodes contacting the retina, still allows test subjects to perform simple visual
tasks. Ongoing engineering research is focusing on the fabrication of a high-resolution
implant.”, “The retina lines the back of the vitreous cavity, a 6-cm 3 space in the back of
the eye that is normally filled with vitreous gel but is routinely replaced with saline
(after removing the vitreous during retinal surgery)(Figure 1). This fluid-filled cavity
will permit a device of significant size to be placed near the retina without disrupting
other tissue.”; “An epiretinal implant will rest on the inner limiting membrane of the
retina, while a subretinal implant would be inserted in the space occupied by
photoreceptors in a healthy retina.”
[52]
A Neuro-Stimulus Chip with Telemetry Unit
for Retinal Prosthetic Device
“It is fabricated by MOSIS with 1.2-mm CMOS technology and was demonstrated to
provide the desired biphasic current stimulus for an array of 100 retinal electrodes at
video frame rates.”, “Over 10,000,000 people worldwide are blind because of
photoreceptor loss due to degenerative retinal diseases such as age-related macular
degeneration (AMD) and retinitis pigmentosa (RP).”, “Medical experiments have
estimated that the equivalent impedance for the retina tissue of RP and AMD patients is
about 10 k and, in the worst case, the current threshold value is about 600 A . Thus,