Phosphoenix raises €1.3M to advance its brain-stimulation neuroprosthetic for profound blindness

Phosphoenix (Amsterdam) has raised €1.3 million from TTT Medtech Fund (managed by 819 Capital), FIRST Fund (managed by BioGeneration Ventures), Innovatiefonds Noord-Holland, and new investor ROM InWest. The first three are existing investors reinvesting; ROM InWest — the Dutch regional development fund for West Holland — is joining for the first time. Founded in 2019 as a spinout from the Netherlands Institute for Neuroscience (KNAW) by Prof. Pieter Roelfsema, Prof. Xing Chen, and Dr. Bert Monna, the company is developing a neuroprosthetic system designed to restore functional vision in people with profound blindness.

The company's approach is to stimulate the lateral geniculate nucleus (LGN) — a relay station in the brain's visual pathway between the eyes and the visual cortex — rather than the retina or visual cortex itself. A camera embedded in a pair of glasses captures the visual scene; a pocket-sized processor converts it to stimulation patterns; those patterns drive the Phosphoenix Fountain Probe, a device with over 1,000 microelectrodes, which stimulates the LGN to create phosphenes — perceived flashes of light that together compose a functional representation of the scene.

The stage of this round is not stated in any source. CEO Hans Brons describes the company as "building towards our Series A financing," placing the current raise in the bridge category.

Why LGN stimulation is different

Existing approved neuroprosthetics for blindness stimulate either the retina (Orion, Argus) or the visual cortex. Both approaches work only when the targeted tissue is intact. Retinal prosthetics are limited to conditions that preserve the inner retinal layers; cortical prosthetics bypass the optic nerve but require navigating into the primary visual cortex, a large surgical target with limited spatial resolution.

The LGN sits between these two anatomical targets. It receives processed signals from the retina via the optic nerve and transmits them to the visual cortex in a highly organised spatial arrangement (the retinotopic map). Phosphoenix's claim is that LGN stimulation can achieve higher spatial resolution than cortical approaches because the structure of the LGN is better organised, and can reach patients with a wider range of underlying causes of blindness — including those with both retinal and optic nerve damage.

The Fountain Probe's 1,000-plus electrode count is a key hardware specification: resolution in a cortical neuroprosthetic is limited by the number and spacing of the electrodes. A denser array at the LGN is the device-level bet that higher-resolution phosphenes are achievable.

What the €1.3 million does

This is not a typical seed or growth round. Brons: "This financing represents an important step towards bringing our technology into the clinic. The continued support of our existing investors, together with the commitment of ROM InWest, provides strong validation of the progress we have made and enables us to advance our first-in-human preparations while building towards our Series A financing."

The money has a specific purpose: preparing the first-in-human (FIH) clinical study at Amsterdam UMC. In medtech, the FIH study is the gate before a pivotal trial; it establishes safety, generates preliminary efficacy data, and defines the parameters for the larger trial that a Series A would fund. The €1.3 million bridges Phosphoenix to that gate. Once the FIH data is available — typically 12-24 months from regulatory clearance to enrolment to readout — the company will have the data package needed to raise the larger round.