A fully intraocular high-density self-calibrating epiretinal prosthesis

Area of Science:

• Biomedical Engineering
• Neuroscience
• Electrical Engineering

Background:

• Epiretinal prostheses aim to restore vision for individuals with retinal degenerative diseases.
• Previous devices faced challenges with calibration, power, and data transmission.
• Fully intraocular systems are desirable for reduced invasiveness.

Purpose of the Study:

• To present a fully intraocular, self-calibrating epiretinal prosthesis with high channel count.
• To detail the novel digital calibration technique and dual-band telemetry system.
• To evaluate the performance and characteristics of the implantable device.

Main Methods:

• Design and fabrication of a 512-channel epiretinal prosthesis using 65 nm CMOS technology.
• Implementation of a novel digital self-calibration technique for biphasic current matching.
• Development of dual-band telemetry for power and data, including an on-chip rectifier and clock recovery.
• Integration with MEMS origami coils and parylene substrate for a fully intraocular implant.

Main Results:

• The prosthesis features 512 independent channels with arbitrary waveform generation.
• An efficient on-chip rectifier achieves >80% efficiency, and data telemetry supports up to 20 Mb/s via PSK modulation.
• In vitro testing demonstrated a low current mismatch (μ = 1.12 μA, σ = 0.53 μA) across multiple channels and chips.
• The system occupies a compact area of 4.5 × 3.1 mm² with a pixel size of 0.0169 mm².

Conclusions:

• The developed fully intraocular epiretinal prosthesis offers a significant advancement in implantable visual prosthetics.
• The novel self-calibration and telemetry systems enable high performance and reduced component count.
• This technology holds promise for improving vision restoration in patients with blindness due to retinal diseases.