Retinal Implant Startups Turn to Optical Technology

by Jeremy Koff, senior consulting editor

November 2023 issue

The market for visual neuroprosthetics products has taken some interesting turns since our last article on this product category earlier this year [NBR Aug23 p1]. Prominent companies like Second Sight Medical Products and Pixium Vision SA, once pioneers in implantable vision restoration devices, now grapple with financial challenges.

In 2022, Second Sight (founded by the famed medical device entrepreneur Alfred Mann) merged with Nano Precision Medical, forming Vivani Medical, Inc. Vivani has stated they are actively exploring strategic options, suggesting an asset sale. Pixium, a promising French company, faced insurmountable financial hurdles, leading to the initiation of a bidding process for the company’s sale after conversion from safeguard proceedings to receivership announced in November 2023. A third company from Australia, Bionic Vision Technologies, continues to commercialize its retinal prosthesis system with some support from the Australian government but is looking for additional financing.

Amidst this landscape, two startup firms have taken a new approach, relying on optogenetic and photoacoustic stimulation rather than electrical stimulation. Both firms intend to target retinitis pigmentosa and AMD with their products.

Axorus, a French company established in 2019 by Helen Moulet Redon, Clemence Cossec, and Jean-Damien Lousie, has emerged with a unique vision restoration initiative. In collaboration with Boston University, Axorus aims to commercialize its patented photoacoustic high precision neurostimulator technology for the retina. Their strategic approach involves subretinally implanting the device precisely where healthy retinas host photoreceptors, targeting individuals with functional but damaged photoreceptors (cones and rods), such as those with retinitis pigmentosa and advanced dry age-related macular degeneration.

Earlier this month, the company announced the successful pre-clinical (in vivo) activation of their high-resolution retinal implant, a significant milestone validated in collaboration with Boston University and the Vision Institute in Paris. This accomplishment builds on ex vivo results achieved earlier in 2023.

At the heart of Axorus’ pioneering technology lies a patented photoacoustic neurostimulator originating from Boston University’s research team. This neurostimulator, paired with a laser, generates ultrasounds with exceptional precision, activating neurons individually. The collaboration with Boston University has given rise to a revolutionary tapered fiber optoacoustic emitter, enabling high-precision optoacoustic activation of single neurons or subcellular structures.

In a Nature article published by Chen Yang et al in 2021, the authors detail the technology and describe how neuromodulation at high spatial precision is able to target a small population or even single neurons or subcellular structures, such as axons and dendrites to alter brain state by using a miniaturized tapered fiber optoacoustic emitter capable of generating an ultrasound field with a 2.7 MPa pressure and a spatial resolution of 39.6 µm. According to the authors, this approach offers an “unprecedented high spatial resolution for ultrasound stimulation.”

Founded in 2019, Axorus has secured modest funding to date. They received an initial seed round of €828,000 in 2019. Their most recent round was an equity crowdfunding in 2020 of $1.3 million. However, to successfully bring this transformative technology to market, significant capital will be needed to avoid the pitfalls experienced by industry predecessors Second Sight and Pixium. With the pressing need for vision restoration solutions, Axorus’ inventive approach to retinal restoration emerges as a promising solution, offering the potential for a significant advancement in the industry.

Another firm, Alameda, CA based Science, is developing visual prosthesis based on optogenetics technology. The firm was co-founded by Max Hodak, who was previously a founder of Elon Musk’s Neuralink BCI firm.

The company’s Science Eye product relies on a protein nanoparticle that delivers a gene to retinal ganglion cells, making them light-sensitive at a specific wavelength. A tiny, flexible high-resolution display film with 8,000 pixels is surgically inserted over the retina to allow fine control of the newly light-sensitive ganglion cells. The electronics package is similar in size to glaucoma shunts widely used today, which are routinely inserted without general anesthesia and can’t be felt by patients once inserted. Glasses worn by the user contain sensors, processing, and batteries which supply power and data to the implant.